





















                                 GGNNUUPPLLOOTT
                     AAnn IInntteerraaccttiivvee PPlloottttiinngg PPrrooggrraamm



                      _T_h_o_m_a_s _W_i_l_l_i_a_m_s _& _C_o_l_i_n _K_e_l_l_e_y
                   _V_e_r_s_i_o_n _4_._0 _o_r_g_a_n_i_z_e_d _b_y_: _L_a_r_s _H_e_c_k_i_n_g
                   _M_a_j_o_r _c_o_n_t_r_i_b_u_t_o_r_s _(_a_l_p_h_a_b_e_t_i_c _o_r_d_e_r_)_:
                           _H_a_n_s_-_B_e_r_n_h_a_r_d _B_r_o_e_k_e_r
                               _J_o_h_n _C_a_m_p_b_e_l_l
                             _R_o_b_e_r_t _C_u_n_n_i_n_g_h_a_m
                               _D_a_v_i_d _D_e_n_h_o_l_m
                               _G_e_r_s_h_o_n _E_l_b_e_r
                               _R_o_g_e_r _F_e_a_r_i_c_k
                              _C_a_r_s_t_e_n _G_r_a_m_m_e_s
                                 _L_u_c_a_s _H_a_r_t
                                _L_a_r_s _H_e_c_k_i_n_g
                               _T_h_o_m_a_s _K_o_e_n_i_g
                                 _D_a_v_i_d _K_o_t_z
                                _E_d _K_u_b_a_i_t_i_s
                                _R_u_s_s_e_l_l _L_a_n_g
                             _A_l_e_x_a_n_d_e_r _L_e_h_m_a_n_n
                               _A_l_e_x_a_n_d_e_r _M_a_i
                               _E_t_h_a_n _M_e_r_r_i_t_t
                                _P_e_t_r _M_i_k_u_l_i_k
                               _C_a_r_s_t_e_n _S_t_e_g_e_r
                                 _T_o_m _T_k_a_c_i_k
                             _J_o_s _V_a_n _d_e_r _W_o_u_d_e
                                  _A_l_e_x _W_o_o
                             _J_a_m_e_s _R_. _V_a_n _Z_a_n_d_t
                              _J_o_h_a_n_n_e_s _Z_e_l_l_n_e_r
     _C_o_p_y_r_i_g_h_t _(_C_) _1_9_8_6 _- _1_9_9_3_, _1_9_9_8_, _2_0_0_4   _T_h_o_m_a_s _W_i_l_l_i_a_m_s_, _C_o_l_i_n _K_e_l_l_e_y
        Mailing list for comments: gnuplot-info@lists.sourceforge.net
      Mailing list for bug reports: gnuplot-bugs@lists.sourceforge.net
                              25 March 2006



















                                    -2-








                This manual was prepared by Dick Crawford.
                             3 December 1998





























































   11..  GGnnuupplloott





   22..  CCooppyyrriigghhtt


         Copyright (C) 1986 - 1993, 1998, 2004   Thomas Williams, Colin
   Kelley

   Permission to use, copy, and distribute this software and its docu-
   mentation for any purpose with or without fee is hereby granted,
   provided that the above copyright notice appear in all copies and
   that both that copyright notice and this permission notice appear in
   supporting documentation.

   Permission to modify the software is granted, but not the right to
   distribute the complete modified source code.  Modifications are to
   be distributed as patches to the released version.  Permission to
   distribute binaries produced by compiling modified sources is
   granted, provided you
     1. distribute the corresponding source modifications from the
      released version in the form of a patch file along with the bina-
   ries,
     2. add special version identification to distinguish your version
      in addition to the base release version number,
     3. provide your name and address as the primary contact for the
      support of your modified version, and
     4. retain our contact information in regard to use of the base
      software.
   Permission to distribute the released version of the source code
   along with corresponding source modifications in the form of a patch
   file is granted with same provisions 2 through 4 for binary distri-
   butions.

   This software is provided "as is" without express or implied war-
   ranty to the extent permitted by applicable law.


         AUTHORS

         Original Software:










   GNUPLOT 4.0                                                        2


            Thomas Williams,  Colin Kelley.

         Gnuplot 2.0 additions:
            Russell Lang, Dave Kotz, John Campbell.

         Gnuplot 3.0 additions:
            Gershon Elber and many others.

         Gnuplot 4.0 additions:
            See list of contributors at head of this document.



   33..  IInnttrroodduuccttiioonn


   ggnnuupplloott is a command-driven interactive function and data plotting
   program.  It is case sensitive (commands and function names written
   in lowercase are not the same as those written in CAPS).  All com-
   mand names may be abbreviated as long as the abbreviation is not
   ambiguous.  Any number of commands may appear on a line (with the
   exception that llooaadd or ccaallll must be the final command), separated by
   semicolons (;).  Strings are indicated with quotes.  They may be
   either single or double quotation marks, e.g.,

         load "filename"
         cd 'dir'

   although there are some subtle differences (see ssyynnttaaxx for more
   details).

   Any command-line arguments are assumed to be names of files contain-
   ing ggnnuupplloott commands, with the exception of standard X11 arguments,
   which are processed first.  Each file is loaded with the llooaadd com-
   mand, in the order specified.  ggnnuupplloott exits after the last file is
   processed.  When no load files are named, ggnnuupplloott enters into an
   interactive mode.  The special filename "-" is used to denote stan-
   dard input.  See "help batch/interactive" for more details.

   Many ggnnuupplloott commands have multiple options.  These options must
   appear in the proper order, although unwanted ones may be omitted in
   most cases.  Thus if the entire command is "command a b c", then
   "command a c" will probably work, but "command c a" will fail.

   Commands may extend over several input lines by ending each line but
   the last with a backslash (\).  The backslash must be the _last_
   character on each line.  The effect is as if the backslash and new-
   line were not there.  That is, no white space is implied, nor is a
   comment terminated.  Therefore, commenting out a continued line com-
   ments out the entire command (see ccoommmmeennttss).  But note that if an
   error occurs somewhere on a multi-line command, the parser may not
   be able to locate precisely where the error is and in that case will
   not necessarily point to the correct line.










   GNUPLOT 4.0                                                        3


   In this document, curly braces ({}) denote optional arguments and a
   vertical bar (|) separates mutually exclusive choices.  ggnnuupplloott key-
   words or hheellpp topics are indicated by backquotes or bboollddffaaccee (where
   available).  Angle brackets (<>) are used to mark replaceable
   tokens.  In many cases, a default value of the token will be taken
   for optional arguments if the token is omitted, but these cases are
   not always denoted with braces around the angle brackets.

   For on-line help on any topic, type hheellpp followed by the name of the
   topic or just hheellpp or ?? to get a menu of available topics.

   The new ggnnuupplloott user should begin by reading about pplloottttiinngg (if on-
   line, type hheellpp pplloottttiinngg).

   See the simple.dem demo, also available together with other demos on
   the web page
             http://www.gnuplot.info/demo/simple.html



   44..  SSeeeekkiinngg--aassssiissttaannccee


   There is a mailing list for ggnnuupplloott users.  Note, however, that the
   newsgroup
         comp.graphics.apps.gnuplot
   is identical to the mailing list (they both carry the same set of
   messages).  We prefer that you read the messages through the news-
   group rather than subscribing to the mailing list.  Instructions for
   subscribing to gnuplot mailing lists may be found via the gnuplot
   development website on SourceForge
             http://sourceforge.net/projects/gnuplot

   The address for mailing to list members is:
         gnuplot-info@lists.sourceforge.net

   Bug reports and code contributions should be mailed to:
         gnuplot-bugs@lists.sourceforge.net

   The list of those interested in beta-test versions is:
         gnuplot-beta@lists.sourceforge.net

   There is also the canonical (if occassionally out-of-date) gnuplot
   web page at

             http://www.gnuplot.info

   Before seeking help, please check the

             FAQ (Frequently Asked Questions) list.

   When posting a question, please include full details of the version
   of ggnnuupplloott, the machine, and operating system you are using.  A










   GNUPLOT 4.0                                                        4


   _small_ script demonstrating the problem may be useful.  Function
   plots are preferable to datafile plots.  If email-ing to gnuplot-
   info, please state whether or not you are subscribed to the list, so
   that users who use news will know to email a reply to you.  There is
   a form for such postings on the WWW site.




   55..  WWhhaatt iiss NNeeww iinn VVeerrssiioonn 44..00


   The previous official release of gnuplot was version 3.7, with sub-
   versions up to 3.7.3. Gnuplot version 4.0 contains many new fea-
   tures, which were gradually introduced into a series of development
   snapshots 3.8a through 3.8k. This section lists major additions and
   gives a partial list of changes and minor new features. Sample gnu-
   plot scripts demonstrating many of these features are provided in
   the gnuplot distribution, and are referred to here by name.





        55..11..  MMoouussee aanndd hhoottkkeeyy ssuuppppoorrtt iinn iinntteerraaccttiivvee tteerrmmiinnaallss



        Interaction with the current plot via mouse and hotkeys is sup-
        ported for the X11, OS/2 Presentation Manager, ggi and Windows
        terminals. See mmoouussee iinnppuutt for more information on mousing. See
        help for bbiinndd for information on hotkeys. Also see the documen-
        tation for individual mousing terminals ggggii, ppmm, wwiinnddoowwss and
        xx1111.

        Here are briefly some useful hotkeys.  Hit 'h' in the interac-
        tive interval for help. Hit 'm' to switch mousing on/off.  Hit
        'g' for grid, 'l' for log and 'e' for replot.  Hit 'r' for
        ruler to measure peak distances (linear scale) or peak ratios
        (log scale), and '5' for polar coordinates inside a map.  Zoom
        by mouse (MB3), and move in the zoom history by 'p', 'u', 'n';
        hit 'a' for autoscale.  Use other mouse buttons to put current
        mouse coordinates to clipboard (double click of MB1), add tem-
        porarily or permanently labels to the plot (middle mouse button
        MB2).  Rotate a 3D surface by mouse.  Hit spacebar to switch to
        the gnuplot command window.

        Sample script: mousevariables.dem















   GNUPLOT 4.0                                                        5


        55..22..  NNeeww tteerrmmiinnaall ffeeaattuurreess



        aaqquuaa: New terminal for Mac OS X. Requires AquaTerm 1.0 or
        later.

        eeppssllaatteexx: New terminal. Prepares eps figures for inclusion in
        LaTeX documents.

        ggiiff: Support for this terminal has been dropped in favour of
        the ppnngg format for legal reasons; under usual configure condi-
        tions, old scripts that request gif will work but will produce
        a ppnngg file instead.

        ggggii: New full-screen interactive terminal for Linux. Interface
        to the General Graphics Interface Library.

        ppddff: New terminal exporting Adobe Portable Document Format.
        Requires libpdf.

        ppnngg and jjppeegg: Support for both PNG and JPEG image output is
        provided by a new driver via libgd. The new driver supports
        many more features than the old png driver, including TrueType
        fonts. Requires libgd.

        ppoossttssccrriipptt: The PostScript driver now provides an oblique sym-
        bol font, and allows run-time inclusion of embedded PostScript
        fonts. It also supports additional character encodings. See
        ppoossttssccrriipptt ffoonnttffiillee and sseett eennccooddiinngg.

        Sample script: fontfile.dem

        ssvvgg: New terminal exporting Scalable Vector Graphics.

        xx1111: The X-windows driver now allows you to specify fonts, see
        sseett tteerrmm xx1111 xx1111__ffoonnttss. There is no longer a limit to the num-
        ber of x11 plot windows opened simultaneously, and each plot
        window can be given its own title. See sseett tteerrmm xx1111.




        55..33..  NNeeww pplloott ssttyyllee ``ppmm33dd``



        The sspplloott command is now capable of plotting 2D maps and 3D
        surfaces colored by greyscale or color palettes. See help for
        sseett ppmm33dd, sseett ppaalleettttee, sseett ccbbrraannggee, sseett vviieeww mmaapp, sseett ccoolloorrbbooxx
        and tteesstt ppaalleettttee.

        Sample scripts: pm3d.dem pm3dcolors.dem pm3dgamma.dem










   GNUPLOT 4.0                                                        6


        55..44..  NNeeww pplloott ssttyyllee ``ffiilllleeddccuurrvveess``



        The style ffiilllleeddccuurrvveess allows to fill an area between the drawn
        curve and a horizontal line.

        Sample script: fillcrvs.dem




        55..55..  FFiilllleedd bbooxxeess



        A solid color or patterned fill style can be set for any plot
        style that contains boxes. See bbooxxeess, bbooxxeerrrroorrbbaarrss, bbooxxxxyyeerrrroorr--
        bbaarrss, ccaannddlleessttiicckkss, sseett ssttyyllee ffiillll.

        Sample scripts: fillstyle.dem candlesticks.dem




        55..66..  NNeeww pplloott ooppttiioonn ssmmooootthh ffrreeqquueennccyy



        Input data can be filtered through several built-in routines
        for interpolation or approximation of data.  See ssmmooootthh, ffrree--
        qquueennccyy, uunniiqquuee.

        Sample scripts: step.dem mgr.dem




        55..77..  IImmpprroovveedd tteexxtt ooppttiioonnss



        Most gnuplot plot commands that produce text labels now accept
        modifiers to specify text color, font, size, and rotation
        angle. See sseett llaabbeell.  Not all terminal types support these
        options, however.  The enhanced text mode previously available
        for the postscript and pm terminals has been extended to other
        terminal types as well.  Terminal types currently supported
        include dumb, jpeg, pdf, pm, png, postscript, and x11. See
        eennhhaanncceedd tteexxtt.

        Sample scripts: textcolor.dem textrotate.dem











   GNUPLOT 4.0                                                        7


        55..88..  MMoorree tteexxtt eennccooddiinnggss



        Several terminals, including ppoossttssccrriipptt, xx1111 and ppmm, support
        additional text eennccooddiinnggss: ISO 8859-1 (Latin 1), ISO 8859-2
        (Latin 2), ISO 8859-15 (variant of 8859-1 with Euro sign),
        KOI8-R (cyrillic), and miscellaneous codepages. See eennccooddiinngg
        for more details.




        55..99..  AArrrroowwss



        Single- or double-ended arrows can be placed on a plot individ-
        ually from the command line or from a data file via the pplloott
        wwiitthh vveeccttoorrss style.  See sseett ssttyyllee aarrrrooww, pplloottttiinngg ssttyylleess vveecc--
        ttoorrss.

        Sample script: arrowstyle.dem




        55..1100..  DDaattaa ffiillee ffoorrmmaatt



        The new sseett ddaattaaffiillee command can be used to specify information
        about the format of input data files, including the characters
        used to separate fields, to indicate comment lines, and to
        specify missing data.  Gnuplot now attempts to recognize text
        fields with embedded blanks as single entities based on the
        datafile format settings.  This allows input from csv (comma-
        separated value) files such as those exported by spreadsheet
        programs. See sseett ddaattaaffiillee.




        55..1111..  OOtthheerr cchhaannggeess aanndd aaddddiittiioonnss



        The preferred syntax to undo a command sseett <<ssoommeetthhiinngg>> is now
        uunnsseett <<ssoommeetthhiinngg>> rather than sseett nnoo<<ssoommeetthhiinngg>>. The older form
        has been deprecated.  Version 4.0 continues to allow the older
        syntax, but such backwards compatibility may be lost in future
        versions.











   GNUPLOT 4.0                                                        8


        Commands of the form sseett <<ssoommeetthhiinngg>> <<ssttyyllee>> also are deprec-
        tated in favor of the more general form sseett ssttyyllee <<ssoommeetthhiinngg>>
        <<ooppttiioonnss>>.  Many more plot elements now have style options of
        their own, including arrows, filled areas, lines, and points.
        There are also style settings for input data and formatting.
        Please see sseett ssttyyllee, sseett ddeecciimmaallssiiggnn, and sseett ddaattaaffiillee.

        Improved 2D and 3D clipping (hidden lines).

        More consistent point styles and other default formatting
        styles across all terminals. Please use the tteesstt command to
        check default styles and plotting capabilities for the cur-
        rently selected terminal type.

        The sseett llaabbeell command supports associated points, and allows
        you to specify point style and text style (font, rotation,
        etc). User variables can be included in labels via format spec-
        ifiers in the label text.  See sseett llaabbeell.

        New command sseett vviieeww mmaapp to select top-view 2D projection of 3D
        surface plot.

        New commands sseett tteerrmm ppuusshh and sseett tteerrmm ppoopp to achieve platform
        independent restoring of the terminal after printing,

        The llooaadd and ssaavvee commands accept piped input and output,
        respectively.

        The hhiissttoorryy command (for gnuplot with its own readline, not
        with GNU readline) now includes several useful options.

        The built-in function rraanndd((xx)) has been modified to allow
        explicit seeding of the pseudo-random number generator. See
        rraannddoomm.

        The MS Windows package includes an additional executable ppggnnuu--
        pplloott..eexxee to support piping command through standard input,
        which is otherwise not available for graphical applications on
        this system.




        55..1122..  AAccccoommppaannyyiinngg ddooccuummeennttaattiioonn



        In directory docs/psdocs/ you may find new information in the
        gnuplot output postscript file guide, list of postscript sym-
        bols in different encodings.

        Improved FAQ. Please read it before asking your question in a
        public forum.










   GNUPLOT 4.0                                                        9


        There are plenty of new demos *.dem in the demo/ directory.
        Please run them, for example by
              load "all.dem"
        before asking for help.  Plots produced by the demo scripts can
        also be viewed at http://www.gnuplot.info/demo/




   66..  BBaattcchh//IInntteerraaccttiivvee OOppeerraattiioonn


   ggnnuupplloott may be executed in either batch or interactive modes, and
   the two may even be mixed together on many systems.

   Any command-line arguments are assumed to be names of files contain-
   ing ggnnuupplloott commands (with the exception of standard X11 arguments,
   which are processed first).  Each file is loaded with the llooaadd com-
   mand, in the order specified.  ggnnuupplloott exits after the last file is
   processed.  When no load files are named, ggnnuupplloott enters into an
   interactive mode.  The special filename "-" is used to denote stan-
   dard input.

   Both the eexxiitt and qquuiitt commands terminate the current command file
   and llooaadd the next one, until all have been processed.

   Examples:

   To launch an interactive session:
         gnuplot

   To launch a batch session using two command files "input1" and
   "input2":
         gnuplot input1 input2

   To launch an interactive session after an initialization file
   "header" and followed by another command file "trailer":
         gnuplot header - trailer



   77..  CCoommmmaanndd--lliinnee--eeddiittiinngg


   Command-line editing is supported by the Unix, Atari, VMS, MS-DOS
   and OS/2 versions of ggnnuupplloott.  Also, a history mechanism allows pre-
   vious commands to be edited and re-executed.  After the command line
   has been edited, a newline or carriage return will enter the entire
   line without regard to where the cursor is positioned.

   (The readline function in ggnnuupplloott is not the same as the readline
   used in GNU Bash and GNU Emacs.  If the GNU version is desired, it
   may be selected instead of the ggnnuupplloott version at compile time.)










   GNUPLOT 4.0                                                       10


   The editing commands are as follows:




      +-------------------------------------------------------------+
      |Character   Function                                         |
      +-------------------------------------------------------------+
      |            Line Editing                                     |
      |   ^B       move back a single character.                    |
      |   ^F       move forward a single character.                 |
      |   ^A       move to the beginning of the line.               |
      |   ^E       move to the end of the line.                     |
      | ^H, DEL    delete the previous character.                   |
      |   ^D       delete the current character.                    |
      |   ^K       delete from current position to the end of line. |
      | ^L, ^R     redraw line in case it gets trashed.             |
      |   ^U       delete the entire line.                          |
      |   ^W       delete from the current word to the end of line. |
      +-------------------------------------------------------------+
      |            History                                          |
      |   ^P       move back through history.                       |
      |   ^N       move forward through history.                    |
      +-------------------------------------------------------------+



   On the IBM PC, the use of a TSR program such as DOSEDIT or CED may
   be desired for line editing.  The default makefile assumes that this
   is the case;  by default ggnnuupplloott will be compiled with no line-edit-
   ing capability.  If you want to use ggnnuupplloott's line editing, set
   READLINE in the makefile and add readline.obj to the link file.  The
   following arrow keys may be used on the IBM PC and Atari versions if
   readline is used:




                     +-------------------------------+
                     |   Arrow key       Function    |
                     +-------------------------------+
                     |   Left Arrow      same as ^B. |
                     |  Right Arrow      same as ^F. |
                     |Ctrl Left Arrow    same as ^A. |
                     |Ctrl Right Arrow   same as ^E. |
                     |    Up Arrow       same as ^P. |
                     |   Down Arrow      same as ^N. |
                     +-------------------------------+
                     +-------------------------------+



   The Atari version of readline defines some additional key aliases:










   GNUPLOT 4.0                                                       11


                     +------------------------------+
                     |   Key      Function          |
                     +------------------------------+
                     |  Undo      same as ^L.       |
                     |  Home      same as ^A.       |
                     |Ctrl Home   same as ^E.       |
                     |   Esc      same as ^U.       |
                     |  Help      help plus return. |
                     |Ctrl Help   help .            |
                     +------------------------------+
                     +------------------------------+





   88..  CCoommmmeennttss


   Comments are supported as follows: a ## may appear in most places in
   a line and ggnnuupplloott will ignore the rest of the line.  It will not
   have this effect inside quotes, inside numbers (including complex
   numbers), inside command substitutions, etc.  In short, it works
   anywhere it makes sense to work.

   See also sseett ddaattaaffiillee ccoommmmeennttsscchhaarrss for specifying comment charac-
   ters in data files.



   99..  CCoooorrddiinnaatteess


   The commands sseett aarrrrooww, sseett kkeeyy, and sseett llaabbeell allow you to draw
   something at an arbitrary position on the graph.  This position is
   specified by the syntax:

         {<system>} <x>, {<system>} <y> {,{<system>} <z>}

   Each <system> can either be ffiirrsstt, sseeccoonndd, ggrraapphh or ssccrreeeenn.

   ffiirrsstt places the x, y, or z coordinate in the system defined by the
   left and bottom axes; sseeccoonndd places it in the system defined by the
   second axes (top and right); ggrraapphh specifies the area within the
   axes---0,0 is bottom left and 1,1 is top right (for splot, 0,0,0 is
   bottom left of plotting area; use negative z to get to the
   base---see sseett ttiiccsslleevveell); and ssccrreeeenn specifies the screen area (the
   entire area---not just the portion selected by sseett ssiizzee), with 0,0
   at bottom left and 1,1 at top right.

   If the coordinate system for x is not specified, ffiirrsstt is used.  If
   the system for y is not specified, the one used for x is adopted.











   GNUPLOT 4.0                                                       12


   If one (or more) axis is timeseries, the appropriate coordinate
   should be given as a quoted time string according to the ttiimmeeffmmtt
   format string.  See sseett xxddaattaa and sseett ttiimmeeffmmtt.  ggnnuupplloott will also
   accept an integer expression, which will be interpreted as seconds
   from 1 January 2000.



   1100..  EEnnvviirroonnmmeenntt


   A number of shell environment variables are understood by ggnnuupplloott.
   None of these are required, but may be useful.

   If GNUTERM is defined, it is used as the name of the terminal type
   to be used.  This overrides any terminal type sensed by ggnnuupplloott on
   start-up, but is itself overridden by the .gnuplot (or equivalent)
   start-up file (see ssttaarrtt--uupp) and, of course, by later explicit
   changes.

   On Unix, AmigaOS, AtariTOS, MS-DOS and OS/2, GNUHELP may be defined
   to be the pathname of the HELP file (gnuplot.gih).

   On VMS, the logical name GNUPLOT$HELP should be defined as the name
   of the help library for ggnnuupplloott.  The ggnnuupplloott help can be put inside
   any system help library, allowing access to help from both within
   and outside ggnnuupplloott if desired.

   On Unix, HOME is used as the name of a directory to search for a
   .gnuplot file if none is found in the current directory.  On Ami-
   gaOS, AtariTOS, MS-DOS, Windows and OS/2, GNUPLOT is used.  On Win-
   dows, the NT-specific variable USERPROFILE is tried, too. VMS,
   SYS$LOGIN: is used. Type hheellpp ssttaarrtt--uupp.

   On Unix, PAGER is used as an output filter for help messages.

   On Unix, AtariTOS and AmigaOS, SHELL is used for the sshheellll command.
   On MS-DOS and OS/2, COMSPEC is used for the sshheellll command.

   On MS-DOS, if the BGI or Watcom interface is used, PCTRM is used to
   tell the maximum resolution supported by your monitor by setting it
   to S<max. horizontal resolution>. E.g. if your monitor's maximum
   resolution is 800x600, then use:
         set PCTRM=S800
   If PCTRM is not set, standard VGA is used.

   FIT_SCRIPT may be used to specify a ggnnuupplloott command to be executed
   when a fit is interrupted---see ffiitt.  FIT_LOG specifies the default
   filename of the logfile maintained by fit.

   GNUPLOT_LIB may be used to define additional search directories for
   data and command files. The variable may contain a single directory
   name, or a list of directories separated by a platform-specific path










   GNUPLOT 4.0                                                       13


   separator, eg. ':' on Unix, or ';' on DOS/Windows/OS/2/Amiga plat-
   forms. The contents of GNUPLOT_LIB are appended to the llooaaddppaatthh
   variable, but not saved with the ssaavvee and ssaavvee sseett commands.

   Several gnuplot terminal drivers access TrueType fonts via the gd
   library.  For these drivers the font search path is controlled by
   the environmental variable GDFONTPATH.  Furthermore, a default font
   for these drivers may be set via the environmental variable GNU-
   PLOT_DEFAULT_GDFONT.

   The postscript terminal uses its own font search path. It is con-
   trolled by the environmental variable GNUPLOT_FONTPATH. The format
   is the same as for GNUPLOT_LIB. The contents of GNUPLOT_FONTPATH are
   appended to the ffoonnttppaatthh variable, but not saved with the ssaavvee and
   ssaavvee sseett commands.



   1111..  EExxpprreessssiioonnss


   In general, any mathematical expression accepted by C, FORTRAN, Pas-
   cal, or BASIC is valid.  The precedence of these operators is deter-
   mined by the specifications of the C programming language.  White
   space (spaces and tabs) is ignored inside expressions.

   Complex constants are expressed as {<real>,<imag>}, where <real> and
   <imag> must be numerical constants.  For example, {3,2} represents 3
   + 2i; {0,1} represents 'i' itself.  The curly braces are explicitly
   required here.

   Note that gnuplot uses both "real" and "integer" arithmetic, like
   FORTRAN and C.  Integers are entered as "1", "-10", etc; reals as
   "1.0", "-10.0", "1e1", 3.5e-1, etc.  The most important difference
   between the two forms is in division: division of integers trun-
   cates: 5/2 = 2; division of reals does not: 5.0/2.0 = 2.5.  In mixed
   expressions, integers are "promoted" to reals before evaluation:
   5/2e0 = 2.5.  The result of division of a negative integer by a pos-
   itive one may vary among compilers.  Try a test like "print -5/2" to
   determine if your system chooses -2 or -3 as the answer.

   The integer expression "1/0" may be used to generate an "undefined"
   flag, which causes a point to ignored; the tteerrnnaarryy operator gives an
   example.

   The real and imaginary parts of complex expressions are always real,
   whatever the form in which they are entered: in {3,2} the "3" and
   "2" are reals, not integers.















   GNUPLOT 4.0                                                       14


        1111..11..  FFuunnccttiioonnss


        The functions in ggnnuupplloott are the same as the corresponding
        functions in the Unix math library, except that all functions
        accept integer, real, and complex arguments, unless otherwise
        noted.

        For those functions that accept or return angles that may be
        given in either degrees or radians (sin(x), cos(x), tan(x),
        asin(x), acos(x), atan(x), atan2(x) and arg(z)), the unit may
        be selected by sseett aanngglleess, which defaults to radians.



















































   GNUPLOT 4.0                                                       15


   +--------------------------------------------------------------------------------+
   |  Function      Arguments    Returns                                            |
   +--------------------------------------------------------------------------------+
   |   abs(x)          any       absolute value of _x, |_x|; same type                |
   |   abs(x)        complex     length of _x, real(_x)2+imag(_x)2                     |
   |  acos(x)          any       cos-1_x (inverse cosine)                            |
   |  acosh(x)         any       cosh-1_x (inverse hyperbolic cosine) in radians     |
   |   arg(x)        complex     the phase of _x                                     |
   |  asin(x)          any       sin-1_x (inverse sin)                               |
   |  asinh(x)         any       sinh-1_x (inverse hyperbolic sin) in radians        |
   |  atan(x)          any       tan-1_x (inverse tangent)                           |
   | atan2(y,x)    int or real   tan-1(_y/_x) (inverse tangent)                       |
   |  atanh(x)         any       tanh-1_x (inverse hyperbolic tangent) in radians    |
   |  besj0(x)     int or real   _j0 Bessel function of _x, in radians                |
   |  besj1(x)     int or real   _j1 Bessel function of _x, in radians                |
   |  besy0(x)     int or real   _y0 Bessel function of _x, in radians                |
   |  besy1(x)     int or real   _y1 Bessel function of _x, in radians                |
   |  ceil(x)          any       _x, smallest integer not less than _x (real part)    |
   |   cos(x)        radians     cos_x, cosine of _x                                  |
   |  cosh(x)          any       cosh_x, hyperbolic cosine of _x in radians           |
   |   erf(x)          any       _e_r_f(real(_x)), error function of real (_x)           |
   |  erfc(x)          any       _e_r_f_c(real(_x)), 1.0 - error function of real (_x)    |
   |   exp(x)          any       _e_x, exponential function of _x                      |
   |  floor(x)         any       _x, largest integer not greater than _x (real part)  |
   |  gamma(x)         any       (real(_x)), gamma function of real (_x)              |
   |ibeta(p,q,x)       any       _i_b_e_t_a(real(_p,_q,_x)), ibeta function of real (_p,_q,_x) |
   | inverf(x)         any       inverse error function real(_x)                     |
   |igamma(a,x)        any       _i_g_a_m_m_a(real(_a,_x)), igamma function of real (_a,_x)   |
   |  imag(x)        complex     imaginary part of _x as a real number               |
   | invnorm(x)        any       inverse normal distribution function real(_x)       |
   |   int(x)         real       integer part of _x, truncated toward zero           |
   |lambertw(x)       real       Lambert W function                                 |
   | lgamma(x)         any       _l_g_a_m_m_a(real(_x)), lgamma function of real (_x)       |
   |   log(x)          any       ln_x, natural logarithm (base _e) of _x               |
   |  log10(x)         any       log10_x, logarithm (base 10) of _x                   |
   |  norm(x)          any       _n_o_r_m(_x), normal distribution function of real(_x)   |
   |  rand(x)          any       _r_a_n_d(_x), pseudo random number generator            |
   |  real(x)          any       real part of _x                                     |
   |   sgn(x)          any       1 if _x>0, -1 if _x<0, 0 if _x=0. imag(_x) ignored     |
   |   sin(x)          any       sin_x, sine of _x                                    |
   |  sinh(x)          any       sinh_x, hyperbolic sine of _x in radians             |
   |  sqrt(x)          any       _x, square root of _x                                |
   |   tan(x)          any       tan_x, tangent of _x                                 |
   |  tanh(x)          any       tanh_x, hyperbolic tangent of _x in radians          |
   +--------------------------------------------------------------------------------+



   A few additional functions are also available.














   GNUPLOT 4.0                                                       16


   +---------------------------------------------------------------------------------+
   | Function      Arguments     Returns                                             |
   +---------------------------------------------------------------------------------+
   |column(x)         int         column _x during datafile manipulation.             |
   |defined(X)   variable name    returns 1 if a variable X is defined, 0 otherwise. |
   |tm_hour(x)        int        the hour                                            |
   |tm_mday(x)        int        the day of the month                                |
   |tm_min(x)         int        the minute                                          |
   |tm_mon(x)         int        the month                                           |
   |tm_sec(x)         int        the second                                          |
   |tm_wday(x)        int        the day of the week                                 |
   |tm_yday(x)        int        the day of the year                                 |
   |tm_year(x)        int        the year                                            |
   | valid(x)         int         test validity of column(_x) during datafile manip.  |
   +---------------------------------------------------------------------------------+


   See also airfoil.dem: use of functions and complex variables for
   airfoils demo.





             1111..11..11..  RRaannddoomm nnuummbbeerr ggeenneerraattoorr



             The behavior of the built-in function rraanndd((xx)) has changed
             as of version 3.8l.  Older scripts that expected rand(x>0)
             to produce sequential pseudo-random numbers from the same
             seeded sequence must be changed to call rand(0) instead.
             The current behavior is as follows:
              `rand(0)`  returns a pseudo random number in the interval
             [0:1] generated
                         from the current value of two internal 32-bit
             seeds.
              `rand(-1)` resets both seeds to a standard value.
              `rand(x)`  for x>0 sets both seeds to a value based on
             the value of x.
              `rand({x,y})` for x>0 sets seed1 to x and seed2 to y.




        1111..22..  OOppeerraattoorrss


        The operators in ggnnuupplloott are the same as the corresponding
        operators in the C programming language, except that all opera-
        tors accept integer, real, and complex arguments, unless other-
        wise noted.  The ** operator (exponentiation) is supported, as
        in FORTRAN.










   GNUPLOT 4.0                                                       17


        Parentheses may be used to change order of evaluation.




             1111..22..11..  UUnnaarryy


             The following is a list of all the unary operators and
             their usages:







    +-----------------------------------------------------------------+
    |Symbol   Example   Explanation                                   |
    +-----------------------------------------------------------------+
    |  -        -a      unary minus                                   |
    |  +        +a      unary plus (no-operation)                     |
    |  ~        ~a      * one's complement                            |
    |  !        !a      * logical negation                            |
    |  !        a!      * factorial                                   |
    |  $        $3      * call arg/column during `using` manipulation |
    +-----------------------------------------------------------------+
    +-----------------------------------------------------------------+


   (*) Starred explanations indicate that the operator requires an
   integer argument.

   Operator precedence is the same as in Fortran and C.  As in those
   languages, parentheses may be used to change the order of operation.
   Thus -2**2 = -4, but (-2)**2 = 4.

   The factorial operator returns a real number to allow a greater
   range.



             1111..22..22..  BBiinnaarryy


             The following is a list of all the binary operators and
             their usages:
















   GNUPLOT 4.0                                                       18


              +--------------------------------------------+
              |Symbol   Example   Explanation              |
              +--------------------------------------------+
              |  **      a**b     exponentiation           |
              |  *        a*b     multiplication           |
              |  /        a/b     division                 |
              |  %        a%b     * modulo                 |
              |  +        a+b     addition                 |
              |  -        a-b     subtraction              |
              |  ==      a==b     equality                 |
              |  !=      a!=b     inequality               |
              |  <        a<b     less than                |
              |  <=      a<=b     less than or equal to    |
              |  >        a>b     greater than             |
              |  >=      a>=b     greater than or equal to |
              |  &        a&b     * bitwise AND            |
              |  ^        a^b     * bitwise exclusive OR   |
              |  |        a|b     * bitwise inclusive OR   |
              |  &&      a&&b     * logical AND            |
              |  ||      a||b     * logical OR             |
              +--------------------------------------------+


   (*) Starred explanations indicate that the operator requires integer
   arguments.

   Logical AND (&&) and OR (||) short-circuit the way they do in C.
   That is, the second &&&& operand is not evaluated if the first is
   false; the second |||| operand is not evaluated if the first is true.



             1111..22..33..  TTeerrnnaarryy


             There is a single ternary operator:




                 +---------------------------------------+
                 |Symbol   Example   Explanation         |
                 +---------------------------------------+
                 |  ?:      a?b:c    * ternary operation |
                 +---------------------------------------+


   The ternary operator behaves as it does in C.  The first argument
   (a), which must be an integer, is evaluated.  If it is true (non-
   zero), the second argument (b) is evaluated and returned; otherwise
   the third argument (c) is evaluated and returned.

   The ternary operator is very useful both in constructing piecewise










   GNUPLOT 4.0                                                       19


   functions and in plotting points only when certain conditions are
   met.

   Examples:

   Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <=
   x < 2, and undefined elsewhere:
         f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
         plot f(x)
   Note that ggnnuupplloott quietly ignores undefined values, so the final
   branch of the function (1/0) will produce no plottable points.  Note
   also that f(x) will be plotted as a continuous function across the
   discontinuity if a line style is used.  To plot it discontinuously,
   create separate functions for the two pieces.  (Parametric functions
   are also useful for this purpose.)

   For data in a file, plot the average of the data in columns 2 and 3
   against the datum in column 1, but only if the datum in column 4 is
   non-negative:

         plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )

   Please see pplloott ddaattaaffiillee uussiinngg for an explanation of the uussiinngg syn-
   tax.



        1111..33..  UUsseerr--ddeeffiinneedd


        New user-defined variables and functions of one through five
        variables may be declared and used anywhere, including on the
        pplloott command itself.

        User-defined function syntax:
              <func-name>( <dummy1> {,<dummy2>} ... {,<dummy5>} ) =
        <expression>

        where <expression> is defined in terms of <dummy1> through
        <dummy5>.

        User-defined variable syntax:
              <variable-name> = <constant-expression>

        Examples:
              w = 2
              q = floor(tan(pi/2 - 0.1))
              f(x) = sin(w*x)
              sinc(x) = sin(pi*x)/(pi*x)
              delta(t) = (t == 0)
              ramp(t) = (t > 0) ? t : 0
              min(a,b) = (a < b) ? a : b
              comb(n,k) = n!/(k!*(n-k)!)










   GNUPLOT 4.0                                                       20


              len3d(x,y,z) = sqrt(x*x+y*y+z*z)
              plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)

        Note that the variable ppii is already defined.  But it is in no
        way magic; you may redefine it to be whatever you like.

        Valid names are the same as in most programming languages: they
        must begin with a letter, but subsequent characters may be let-
        ters, digits, "$", or "_".  Note, however, that the ffiitt mecha-
        nism uses several variables with names that begin "FIT_".  It
        is safest to avoid using such names.  "FIT_LIMIT", however, is
        one that you may wish to redefine. See the documentation on ffiitt
        for details.

        See sshhooww ffuunnccttiioonnss, sshhooww vvaarriiaabblleess, and ffiitt.




   1122..  GGlloossssaarryy


   Throughout this document an attempt has been made to maintain con-
   sistency of nomenclature.  This cannot be wholly successful because
   as ggnnuupplloott has evolved over time, certain command and keyword names
   have been adopted that preclude such perfection.  This section con-
   tains explanations of the way some of these terms are used.

   A "page" or "screen" is the entire area addressable by ggnnuupplloott.  On
   a monitor, it is the full screen; on a plotter, it is a single sheet
   of paper.

   A screen may contain one or more "plots".  A plot is defined by an
   abscissa and an ordinate, although these need not actually appear on
   it, as well as the margins and any text written therein.

   A plot contains one "graph".  A graph is defined by an abscissa and
   an ordinate, although these need not actually appear on it.

   A graph may contain one or more "lines".  A line is a single func-
   tion or data set.  "Line" is also a plotting style.  The word will
   also be used in sense "a line of text".  Presumably the context will
   remove any ambiguity.

   The lines on a graph may have individual names.  These may be listed
   together with a sample of the plotting style used to represent them
   in the "key", sometimes also called the "legend".

   The word "title" occurs with multiple meanings in ggnnuupplloott.  In this
   document, it will always be preceded by the adjective "plot",
   "line", or "key" to differentiate among them.

   A 2-d graph may have up to four labelled axes.  The names of the










   GNUPLOT 4.0                                                       21


   four axes for these usages are "x" for the axis along the bottom
   border of the plot, "y" for the left border, "x2" for the top bor-
   der, and "y2" for the right border.

   A 3-d graph may have up to three labelled axes -- "x", "y" and "z".
   It is not possible to say where on the graph any particular axis
   will fall because you can change the direction from which the graph
   is seen with sseett vviieeww.

   When discussing data files, the term "record" will be resurrected
   and used to denote a single line of text in the file, that is, the
   characters between newline or end-of-record characters.  A "point"
   is the datum extracted from a single record.  A "datablock" is a set
   of points from consecutive records, delimited by blank records.  A
   line, when referred to in the context of a data file, is a subset of
   a datablock.



   1133..  MMoouussee iinnppuutt


   The xx1111, ppmm, wwiinnddoowwss, and ggggii terminals allow interaction with the
   current plot using the mouse. They also support the definition of
   hotkeys to activate pre-defined functions by hitting a single key
   while the mouse focus is in the active plot window.  It is even pos-
   sible to combine mouse input with bbaattcchh command scripts, by invoking
   the command ppaauussee mmoouussee and then using the mouse variables returned
   by mouse clicking as parameters for subsequent scripted actions. See
   bbiinndd and mmoouussee vvaarriiaabblleess.  See also the command sseett mmoouussee.





        1133..11..  BBiinndd


        The bbiinndd allows defining or redefining a hotkey, i.e. a
        sequence of gnuplot commands which will be executed when a cer-
        tain key or key sequence is pressed while the driver's window
        has the input focus. Note that bbiinndd is only available if gnu-
        plot was compiled with mmoouussee support and it is used by all
        mouse-capable terminals. Bindings overwrite the builtin bind-
        ings (like in every real editor), except <space> and 'q' which
        cannot be rebound. Mouse buttons cannot be rebound.

        Note that multikey-bindings with modifiers have to be quoted.

        Syntax:
              bind [<key-sequence>] ["<gnuplot commands>"]
              bind!











   GNUPLOT 4.0                                                       22


        Examples:

        - set bindings:

            bind a "replot"
            bind "ctrl-a" "plot x*x"
            bind "ctrl-alt-a" 'print "great"'
            bind Home "set view 60,30; replot"

        - show bindings:
            bind "ctrl-a"          # shows the binding for ctrl-a
            bind                   # shows all bindings

        - remove bindings:
            bind "ctrl-alt-a" ""   # removes binding for ctrl-alt-a
                                     (note that builtins cannot be
        removed)
            bind!                  # installs default (builtin) bind-
        ings

        - bind a key to toggle something:
          v=0
          bind "ctrl-r" "v=v+1;if(v%2)set term x11 noraise; else set
        term x11 raise"

        Modifiers (ctrl / alt) are case insensitive, keys not:
            ctrl-alt-a == CtRl-alT-a
            ctrl-alt-a != ctrl-alt-A

        List of modifiers (alt == meta):
            ctrl, alt

        List of supported special keys:

           "BackSpace", "Tab", "Linefeed", "Clear", "Return", "Pause",
        "Scroll_Lock",
           "Sys_Req", "Escape", "Delete", "Home", "Left", "Up",
        "Right", "Down",
           "PageUp", "PageDown", "End", "Begin",

           "KP_Space", "KP_Tab", "KP_Enter", "KP_F1", "KP_F2", "KP_F3",
        "KP_F4",
           "KP_Home", "KP_Left", "KP_Up", "KP_Right", "KP_Down",
        "KP_PageUp",
           "KP_PageDown", "KP_End", "KP_Begin", "KP_Insert",
        "KP_Delete", "KP_Equal",
           "KP_Multiply", "KP_Add", "KP_Separator", "KP_Subtract",
        "KP_Decimal",
           "KP_Divide",

           "KP_1" - "KP_9", "F1" - "F12"

        See also help for mmoouussee and iiff.










   GNUPLOT 4.0                                                       23


        1133..22..  MMoouussee__vvaarriiaabblleess


        When mousing is active, clicking in the active window will set
        several user variables that can be accessed from the gnuplot
        command line. The coordinates of the mouse at the time of the
        click are stored in MOUSE_X MOUSE_Y MOUSE_X2 and MOUSE_Y2. The
        mouse button clicked, and any meta-keys active at that time,
        are stored in MOUSE_BUTTON MOUSE_SHIFT MOUSE_ALT and
        MOUSE_CTRL.  These variables are set to undefined at the start
        of every plot, and only become defined in the event of a mouse
        click in the active plot window. To determine from a script if
        the mouse has been clicked in the active plot window, it is
        sufficient to test for any one of these variables being
        defined.

              plot 'something'
              set pause mouse
              if (defined(MOUSE_BUTTON)) call 'something_else'; \
              else print "No mouse click."




   1144..  PPlloottttiinngg


   There are three ggnnuupplloott commands which actually create a plot: pplloott,
   sspplloott and rreepplloott.  pplloott generates 2-d plots, sspplloott generates 3-d
   plots (actually 2-d projections, of course), and rreepplloott appends its
   arguments to the previous pplloott or sspplloott and executes the modified
   command.

   Much of the general information about plotting can be found in the
   discussion of pplloott; information specific to 3-d can be found in the
   sspplloott section.

   pplloott operates in either rectangular or polar coordinates -- see sseett
   ppoollaarr for details of the latter.  sspplloott operates only in rectangular
   coordinates, but the sseett mmaappppiinngg command allows for a few other
   coordinate systems to be treated.  In addition, the uussiinngg option
   allows both pplloott and sspplloott to treat almost any coordinate system
   you'd care to define.

   pplloott also lets you use each of the four borders -- x (bottom), x2
   (top), y (left) and y2 (right) -- as an independent axis.  The aaxxeess
   option lets you choose which pair of axes a given function or data
   set is plotted against.  A full complement of sseett commands exists to
   give you complete control over the scales and labelling of each
   axis.  Some commands have the name of an axis built into their
   names, such as sseett xxllaabbeell.  Other commands have one or more axis
   names as options, such as sseett llooggssccaallee xxyy.  Commands and options
   controlling the z axis have no effect on 2-d graphs.










   GNUPLOT 4.0                                                       24


   sspplloott can plot surfaces and contours in addition to points and/or
   lines.  In addition to sspplloott, see sseett iissoossaammpplleess for information
   about defining the grid for a 3-d function;  sspplloott ddaattaaffiillee for
   information about the requisite file structure for 3-d data values;
   and sseett ccoonnttoouurr and sseett ccnnttrrppaarraamm for information about contours.

   In sspplloott, control over the scales and labels of the axes are the
   same as with pplloott, except that commands and options controlling the
   x2 and y2 axes have no effect whereas of course those controlling
   the z axis do take effect.

   sspplloott allows plotting of binary and matrix data, but only for spe-
   cific data formats.  See sspplloott for details.



   1155..  SSttaarrtt--uupp


   When ggnnuupplloott is run, it looks for an initialization file to load.
   This file is called ..ggnnuupplloott on Unix and AmigaOS systems, and GGNNUU--
   PPLLOOTT..IINNII on other systems.  If this file is not found in the current
   directory, the program will look for it in the HOME directory (under
   AmigaOS, Atari(single)TOS, MS-DOS, Windows and OS/2, the environment
   variable GGNNUUPPLLOOTT should contain the name of this directory; on Win-
   dows NT, it will use UUSSEERRPPRROOFFIILLEE if GNUPLOT isn't defined).  Note:
   if NOCWDRC is defined during the installation, ggnnuupplloott will not read
   from the current directory.

   If the initialization file is found, ggnnuupplloott executes the commands
   in it.  These may be any legal ggnnuupplloott commands, but typically they
   are limited to setting the terminal and defining frequently-used
   functions or variables.



   1166..  SSuubbssttiittuuttiioonn


   Command-line substitution is specified by a system command enclosed
   in backquotes.  This command is spawned and the output it produces
   replaces the name of the command (and backquotes) on the command
   line.  Some implementations also support pipes;  see pplloott ddaattaaffiillee
   ssppeecciiaall--ffiilleennaammeess.

   Command-line substitution can be used anywhere on the ggnnuupplloott com-
   mand line, except inside strings delimited by single quotes.

   Example:

   This will run the program lleeaassttssqq and replace lleeaassttssqq (including
   backquotes) on the command line with its output:
         f(x) = `leastsq`










   GNUPLOT 4.0                                                       25


   or, in VMS
         f(x) = `run leastsq`

   These will generate labels with the current time and userid:
         set label "generated on `date +%Y-%m-%d`by `whoami`" at 1,1
         set timestamp "generated on %Y-%m-%d by `whoami`"




   1177..  SSyynnttaaxx


   The general rules of syntax and punctuation in ggnnuupplloott are that key-
   words and options are order-dependent.  Options and any accompanying
   parameters are separated by spaces whereas lists and coordinates are
   separated by commas.  Ranges are separated by colons and enclosed in
   brackets [], text and file names are enclosed in quotes, and a few
   miscellaneous things are enclosed in parentheses.  Braces {} are
   used for a few special purposes.

   Commas are used to separate coordinates on the sseett commands aarrrrooww,
   kkeeyy, and llaabbeell; the list of variables being fitted (the list after
   the vviiaa keyword on the ffiitt command); lists of discrete contours or
   the loop parameters which specify them on the sseett ccnnttrrppaarraamm command;
   the arguments of the sseett commands ddggrriidd33dd, dduummmmyy, iissoossaammpplleess, ooffff--
   sseettss, oorriiggiinn, ssaammpplleess, ssiizzee, ttiimmee, and vviieeww; lists of tics or the
   loop parameters which specify them; the offsets for titles and axis
   labels; parametric functions to be used to calculate the x, y, and z
   coordinates on the pplloott, rreepplloott and sspplloott commands; and the complete
   sets of keywords specifying individual plots (data sets or func-
   tions) on the pplloott, rreepplloott and sspplloott commands.

   Parentheses are used to delimit sets of explicit tics (as opposed to
   loop parameters) and to indicate computations in the uussiinngg filter of
   the ffiitt, pplloott, rreepplloott and sspplloott commands.

   (Parentheses and commas are also used as usual in function nota-
   tion.)

   Brackets are used to delimit ranges, whether they are given on sseett,
   pplloott or sspplloott commands.

   Colons are used to separate extrema in rraannggee specifications (whether
   they are given on sseett, pplloott or sspplloott commands) and to separate
   entries in the uussiinngg filter of the pplloott, rreepplloott, sspplloott and ffiitt com-
   mands.

   Semicolons are used to separate commands given on a single command
   line.

   Braces are used in text to be specially processed by some terminals,
   like ppoossttssccrriipptt.  They are also used to denote complex numbers:










   GNUPLOT 4.0                                                       26


   {3,2} = 3 + 2i.

   Text may be enclosed in single- or double-quotes.  Backslash pro-
   cessing of sequences like \n (newline) and \345 (octal character
   code) is performed for double-quoted strings, but not for single-
   quoted strings.

   The justification is the same for each line of a multi-line string.
   Thus the center-justified string
         "This is the first line of text.\nThis is the second line."
   will produce
                          This is the first line of text.
                             This is the second line.
   but
         'This is the first line of text.\nThis is the second line.'
   will produce
             This is the first line of text.\nThis is the second line.

   Filenames may be entered with either single- or double-quotes.  In
   this manual the command examples generally single-quote filenames
   and double-quote other string tokens for clarity.

   At present you should not embed \n inside {} when using the eennhhaanncceedd
   ppoossttssccrriipptt terminal.

   The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow a newline
   to be specified by \\ in a single-quoted string or \\\\ in a double-
   quoted string.

   Back-quotes are used to enclose system commands for substitution.



   1188..  TTiimmee//DDaattee ddaattaa


   ggnnuupplloott supports the use of time and/or date information as input
   data.  This feature is activated by the commands sseett xxddaattaa ttiimmee, sseett
   yyddaattaa ttiimmee, etc.

   Internally all times and dates are converted to the number of sec-
   onds from the year 2000.  The command sseett ttiimmeeffmmtt defines the format
   for all inputs: data files, ranges, tics, label positions---in
   short, anything that accepts a data value must receive it in this
   format.  Since only one input format can be in force at a given
   time, all time/date quantities being input at the same time must be
   presented in the same format.  Thus if both x and y data in a file
   are time/date, they must be in the same format.

   The conversion to and from seconds assumes Universal Time (which is
   the same as Greenwich Standard Time).  There is no provision for
   changing the time zone or for daylight savings.  If all your data
   refer to the same time zone (and are all either daylight or










   GNUPLOT 4.0                                                       27


   standard) you don't need to worry about these things.  But if the
   absolute time is crucial for your application, you'll need to con-
   vert to UT yourself.

   Commands like sshhooww xxrraannggee will re-interpret the integer according to
   ttiimmeeffmmtt.  If you change ttiimmeeffmmtt, and then sshhooww the quantity again,
   it will be displayed in the new ttiimmeeffmmtt.  For that matter, if you
   give the deactivation command (like sseett xxddaattaa), the quantity will be
   shown in its numerical form.

   The command sseett ffoorrmmaatt defines the format that will be used for tic
   labels, whether or not the specified axis is time/date.

   If time/date information is to be plotted from a file, the uussiinngg
   option _must_ be used on the pplloott or sspplloott command.  These commands
   simply use white space to separate columns, but white space may be
   embedded within the time/date string.  If you use tabs as a separa-
   tor, some trial-and-error may be necessary to discover how your sys-
   tem treats them.

   The following example demonstrates time/date plotting.

   Suppose the file "data" contains records like

         03/21/95 10:00  6.02e23

   This file can be plotted by

         set xdata time
         set timefmt "%m/%d/%y"
         set xrange ["03/21/95":"03/22/95"]
         set format x "%m/%d"
         set timefmt "%m/%d/%y %H:%M"
         plot "data" using 1:3

   which will produce xtic labels that look like "03/21".

   See the descriptions of each command for more details.




   1199..  CCoommmmaannddss


   This section lists the commands acceptable to ggnnuupplloott in alphabeti-
   cal order.  Printed versions of this document contain all commands;
   on-line versions may not be complete.  Indeed, on some systems there
   may be no commands at all listed under this heading.

   Note that in most cases unambiguous abbreviations for command names
   and their options are permissible, i.e., "pp ff((xx)) ww llii" instead of
   "pplloott ff((xx)) wwiitthh lliinneess".










   GNUPLOT 4.0                                                       28


   In the syntax descriptions, braces ({}) denote optional arguments
   and a vertical bar (|) separates mutually exclusive choices.



   2200..  CCdd


   The ccdd command changes the working directory.

   Syntax:
         cd '<directory-name>'

   The directory name must be enclosed in quotes.

   Examples:
         cd 'subdir'
         cd ".."

   DOS users _must_ use single-quotes---backslash [\] has special sig-
   nificance inside double-quotes.  For example,
         cd "c:\newdata"
   fails, but
         cd 'c:\newdata'
   works as expected.



   2211..  CCaallll


   The ccaallll command is identical to the load command with one excep-
   tion: you can have up to ten additional parameters to the command
   (delimited according to the standard parser rules) which can be sub-
   stituted into the lines read from the file.  As each line is read
   from the ccaalllled input file, it is scanned for the sequence $$ (dol-
   lar-sign) followed by a digit (0--9).  If found, the sequence is
   replaced by the corresponding parameter from the ccaallll command line.
   If the parameter was specified as a string in the ccaallll line, it is
   substituted without its enclosing quotes.  $$ followed by any charac-
   ter other than a digit will be that character.  E.g. use $$$$ to get a
   single $$.  Providing more than ten parameters on the ccaallll command
   line will cause an error.  A parameter that was not provided substi-
   tutes as nothing.  Files being ccaalllled may themselves contain ccaallll or
   llooaadd commands.

   The ccaallll command _must_ be the last command on a multi-command line.

   Syntax:
         call "<input-file>" <parameter-0> <parm-1> ... <parm-9>

   The name of the input file must be enclosed in quotes, and it is
   recommended that parameters are similarly enclosed in quotes (future










   GNUPLOT 4.0                                                       29


   versions of gnuplot may treat quoted and unquoted arguments differ-
   ently).

   Example:

   If the file 'calltest.gp' contains the line:
         print "p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"

   entering the command:
         call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"

   will display:
         p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx

   NOTE: there is a clash in syntax with the datafile uussiinngg callback
   operator.  Use $$$$nn or ccoolluummnn((nn)) to access column n from a datafile
   inside a ccaalllled datafile plot.



   2222..  CClleeaarr


   The cclleeaarr command erases the current screen or output device as
   specified by sseett oouuttppuutt.  This usually generates a formfeed on hard-
   copy devices.  Use sseett tteerrmmiinnaall to set the device type.

   For some terminals cclleeaarr erases only the portion of the plotting
   surface defined by sseett ssiizzee, so for these it can be used in conjunc-
   tion with sseett mmuullttiipplloott to create an inset.

   Example:
         set multiplot
         plot sin(x)
         set origin 0.5,0.5
         set size 0.4,0.4
         clear
         plot cos(x)
         unset multiplot

   Please see sseett mmuullttiipplloott, sseett ssiizzee, and sseett oorriiggiinn for details of
   these commands.



   2233..  EExxiitt


   The commands eexxiitt and qquuiitt and the END-OF-FILE character will exit
   the current ggnnuupplloott command file and llooaadd the next one.  See "help
   batch/interactive" for more details.

   Each of these commands will clear the output device (as does the










   GNUPLOT 4.0                                                       30


   cclleeaarr command) before exiting.



   2244..  FFiitt


   The ffiitt command can fit a user-defined function to a set of data
   points (x,y) or (x,y,z), using an implementation of the nonlinear
   least-squares (NLLS) Marquardt-Levenberg algorithm.  Any user-
   defined variable occurring in the function body may serve as a fit
   parameter, but the return type of the function must be real.

   Syntax:
         fit {[xrange] {[yrange]}} <function> '<datafile>'
             {datafile-modifiers}
             via '<parameter file>' | <var1>{,<var2>,...}

   Ranges may be specified to temporarily limit the data which is to be
   fitted; any out-of-range data points are ignored. The syntax is
         [{dummy_variable=}{<min>}{:<max>}],
   analogous to pplloott; see pplloott rraannggeess.

   <function> is any valid ggnnuupplloott expression, although it is usual to
   use a previously user-defined function of the form f(x) or f(x,y).

   <datafile> is treated as in the pplloott command.  All the pplloott ddaattaaffiillee
   modifiers (uussiinngg, eevveerryy,...) except ssmmooootthh and the deprecated tthhrruu
   are applicable to ffiitt. See pplloott ddaattaaffiillee.

   The default data formats for fitting functions with a single inde-
   pendent variable, y=f(x), are {x:}y or x:y:s; those formats can be
   changed with the datafile uussiinngg qualifier.  The third item (a column
   number or an expression), if present, is interpreted as the standard
   deviation of the corresponding y value and is used to compute a
   weight for the datum, 1/s**2.  Otherwise, all data points are
   weighted equally, with a weight of one.  Note that if you don't
   specify a uussiinngg option at all, no y deviations are read from the
   datafile even if it does have a third column, so you'll always get
   unit weights.

   To fit a function with two independent variables, z=f(x,y), the
   required format is uussiinngg with four items, x:y:z:s.  The complete
   format must be given---no default columns are assumed for a missing
   token.  Weights for each data point are evaluated from 's' as above.
   If error estimates are not available, a constant value can be speci-
   fied as a constant expression (see pplloott ddaattaaffiillee uussiinngg), e.g., uussiinngg
   11::22::33::((11)).

   Multiple datasets may be simultaneously fit with functions of one
   independent variable by making y a 'pseudo-variable', e.g., the
   dataline number, and fitting as two independent variables.  See ffiitt
   mmuullttii--bbrraanncchh.










   GNUPLOT 4.0                                                       31


   The vviiaa qualifier specifies which parameters are to be adjusted,
   either directly, or by referencing a parameter file.

   Examples:
         f(x) = a*x**2 + b*x + c
         g(x,y) = a*x**2 + b*y**2 + c*x*y
         FIT_LIMIT = 1e-6
         fit f(x) 'measured.dat' via 'start.par'
         fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
         fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
         fit g(x,y) 'surface.dat' using 1:2:3:(1) via a, b, c

   After each iteration step, detailed information about the current
   state of the fit is written to the display.  The same information
   about the initial and final states is written to a log file,
   "fit.log".  This file is always appended to, so as to not lose any
   previous fit history;  it should be deleted or renamed as desired.
   By using the command sseett ffiitt llooggffiillee, the name of the log file can
   be changed.

   If gnuplot was built with this option, and you activated it using
   sseett ffiitt eerrrroorrvvaarriiaabblleess, the error for each fitted parameter will be
   stored in a variable named like the parameter, but with "_err"
   appended.  Thus the errors can be used as input for further computa-
   tions.

   The fit may be interrupted by pressing Ctrl-C (any key but Ctrl-C
   under MSDOS and Atari Multitasking Systems).  After the current
   iteration completes, you have the option to (1) stop the fit and
   accept the current parameter values, (2) continue the fit, (3) exe-
   cute a ggnnuupplloott command as specified by the environment variable
   FIT_SCRIPT.  The default for FIT_SCRIPT is rreepplloott, so if you had
   previously plotted both the data and the fitting function in one
   graph, you can display the current state of the fit.

   Once ffiitt has finished, the uuppddaattee command may be used to store final
   values in a file for subsequent use as a parameter file.   See
   uuppddaattee for details.




        2244..11..  AAddjjuussttaabbllee ppaarraammeetteerrss


        There are two ways that vviiaa can specify the parameters to be
        adjusted, either directly on the command line or indirectly, by
        referencing a parameter file.  The two use different means to
        set initial values.

        Adjustable parameters can be specified by a comma-separated
        list of variable names after the vviiaa keyword.  Any variable
        that is not already defined is created with an initial value of










   GNUPLOT 4.0                                                       32


        1.0.  However, the fit is more likely to converge rapidly if
        the variables have been previously declared with more appropri-
        ate starting values.

        In a parameter file, each parameter to be varied and a corre-
        sponding initial value are specified, one per line, in the form
              varname = value

        Comments, marked by '#', and blank lines are permissible.  The
        special form
              varname = value       # FIXED

        means that the variable is treated as a 'fixed parameter', ini-
        tialized by the parameter file, but not adjusted by ffiitt.  For
        clarity, it may be useful to designate variables as fixed
        parameters so that their values are reported by ffiitt.  The key-
        word ## FFIIXXEEDD has to appear in exactly this form.




        2244..22..  SShhoorrtt iinnttrroodduuccttiioonn


        ffiitt is used to find a set of parameters that 'best' fits your
        data to your user-defined function.  The fit is judged on the
        basis of the sum of the squared differences or 'residuals'
        (SSR) between the input data points and the function values,
        evaluated at the same places.  This quantity is often called
        'chisquare' (i.e., the Greek letter chi, to the power of 2).
        The algorithm attempts to minimize SSR, or more precisely,
        WSSR, as the residuals are 'weighted' by the input data errors
        (or 1.0) before being squared; see ffiitt eerrrroorr__eessttiimmaatteess for
        details.

        That's why it is called 'least-squares fitting'.  Let's look at
        an example to see what is meant by 'non-linear', but first we
        had better go over some terms.  Here it is convenient to use z
        as the dependent variable for user-defined functions of either
        one independent variable, z=f(x), or two independent variables,
        z=f(x,y).  A parameter is a user-defined variable that ffiitt will
        adjust, i.e., an unknown quantity in the function declaration.
        Linearity/non-linearity refers to the relationship of the
        dependent variable, z, to the parameters which ffiitt is adjust-
        ing, not of z to the independent variables, x and/or y.  (To be
        technical, the second {and higher} derivatives of the fitting
        function with respect to the parameters are zero for a linear
        least-squares problem).

        For linear least-squares (LLS), the user-defined function will
        be a sum of simple functions, not involving any parameters,
        each multiplied by one parameter.  NLLS handles more compli-
        cated functions in which parameters can be used in a large










   GNUPLOT 4.0                                                       33


        number of ways.  An example that illustrates the difference
        between linear and nonlinear least-squares is the Fourier
        series.  One member may be written as
             z=a*sin(c*x) + b*cos(c*x).
        If a and b are the unknown parameters and c is constant, then
        estimating values of the parameters is a linear least-squares
        problem.  However, if c is an unknown parameter, the problem is
        nonlinear.

        In the linear case, parameter values can be determined by com-
        paratively simple linear algebra, in one direct step.  However
        LLS is a special case which is also solved along with more gen-
        eral NLLS problems by the iterative procedure that ggnnuupplloott
        uses.  ffiitt attempts to find the minimum by doing a search.
        Each step (iteration) calculates WSSR with a new set of parame-
        ter values.  The Marquardt-Levenberg algorithm selects the
        parameter values for the next iteration.  The process continues
        until a preset criterion is met, either (1) the fit has "con-
        verged" (the relative change in WSSR is less than FIT_LIMIT),
        or (2) it reaches a preset iteration count limit, FIT_MAXITER
        (see ffiitt ccoonnttrrooll vvaarriiaabblleess).  The fit may also be interrupted
        and subsequently halted from the keyboard (see ffiitt).

        Often the function to be fitted will be based on a model (or
        theory) that attempts to describe or predict the behaviour of
        the data.  Then ffiitt can be used to find values for the free
        parameters of the model, to determine how well the data fits
        the model, and to estimate an error range for each parameter.
        See ffiitt eerrrroorr__eessttiimmaatteess.

        Alternatively, in curve-fitting, functions are selected inde-
        pendent of a model (on the basis of experience as to which are
        likely to describe the trend of the data with the desired reso-
        lution and a minimum number of parameters*functions.)  The ffiitt
        solution then provides an analytic representation of the curve.

        However, if all you really want is a smooth curve through your
        data points, the ssmmooootthh option to pplloott may be what you've been
        looking for rather than ffiitt.



        2244..33..  EErrrroorr eessttiimmaatteess


        In ffiitt, the term "error" is used in two different contexts,
        data error estimates and parameter error estimates.

        Data error estimates are used to calculate the relative weight
        of each data point when determining the weighted sum of squared
        residuals, WSSR or chisquare.  They can affect the parameter
        estimates, since they determine how much influence the devia-
        tion of each data point from the fitted function has on the










   GNUPLOT 4.0                                                       34


        final values.  Some of the ffiitt output information, including
        the parameter error estimates, is more meaningful if accurate
        data error estimates have been provided.

        The 'statistical overview' describes some of the ffiitt output and
        gives some background for the 'practical guidelines'.




             2244..33..11..  SSttaattiissttiiccaall oovveerrvviieeww


             The theory of non-linear least-squares (NLLS) is generally
             described in terms of a normal distribution of errors,
             that is, the input data is assumed to be a sample from a
             population having a given mean and a Gaussian (normal)
             distribution about the mean with a given standard devia-
             tion.  For a sample of sufficiently large size, and know-
             ing the population standard deviation, one can use the
             statistics of the chisquare distribution to describe a
             "goodness of fit" by looking at the variable often called
             "chisquare".  Here, it is sufficient to say that a reduced
             chisquare (chisquare/degrees of freedom, where degrees of
             freedom is the number of datapoints less the number of
             parameters being fitted) of 1.0 is an indication that the
             weighted sum of squared deviations between the fitted
             function and the data points is the same as that expected
             for a random sample from a population characterized by the
             function with the current value of the parameters and the
             given standard deviations.

             If the standard deviation for the population is not con-
             stant, as in counting statistics where variance = counts,
             then each point should be individually weighted when com-
             paring the observed sum of deviations and the expected sum
             of deviations.

             At the conclusion ffiitt reports 'stdfit', the standard devi-
             ation of the fit, which is the rms of the residuals, and
             the variance of the residuals, also called 'reduced
             chisquare' when the data points are weighted.  The number
             of degrees of freedom (the number of data points minus the
             number of fitted parameters) is used in these estimates
             because the parameters used in calculating the residuals
             of the datapoints were obtained from the same data.

             To estimate confidence levels for the parameters, one can
             use the minimum chisquare obtained from the fit and
             chisquare statistics to determine the value of chisquare
             corresponding to the desired confidence level, but consid-
             erably more calculation is required to determine the com-
             binations of parameters which produce such values.










   GNUPLOT 4.0                                                       35


             Rather than determine confidence intervals, ffiitt reports
             parameter error estimates which are readily obtained from
             the variance-covariance matrix after the final iteration.
             By convention, these estimates are called "standard
             errors" or "asymptotic standard errors", since they are
             calculated in the same way as the standard errors (stan-
             dard deviation of each parameter) of a linear least-
             squares problem, even though the statistical conditions
             for designating the quantity calculated to be a standard
             deviation are not generally valid for the NLLS problem.
             The asymptotic standard errors are generally over-opti-
             mistic and should not be used for determining confidence
             levels, but are useful for qualitative purposes.

             The final solution also produces a correlation matrix,
             which gives an indication of the correlation of parameters
             in the region of the solution; if one parameter is
             changed, increasing chisquare, does changing another com-
             pensate?  The main diagonal elements, autocorrelation, are
             all 1; if all parameters were independent, all other ele-
             ments would be nearly 0.  Two variables which completely
             compensate each other would have an off-diagonal element
             of unit magnitude, with a sign depending on whether the
             relation is proportional or inversely proportional.  The
             smaller the magnitudes of the off-diagonal elements, the
             closer the estimates of the standard deviation of each
             parameter would be to the asymptotic standard error.



             2244..33..22..  PPrraaccttiiccaall gguuiiddeelliinneess


             If you have a basis for assigning weights to each data
             point, doing so lets you make use of additional knowledge
             about your measurements, e.g., take into account that some
             points may be more reliable than others.  That may affect
             the final values of the parameters.

             Weighting the data provides a basis for interpreting the
             additional ffiitt output after the last iteration.  Even if
             you weight each point equally, estimating an average stan-
             dard deviation rather than using a weight of 1 makes WSSR
             a dimensionless variable, as chisquare is by definition.

             Each fit iteration will display information which can be
             used to evaluate the progress of the fit.  (An '*' indi-
             cates that it did not find a smaller WSSR and is trying
             again.)  The 'sum of squares of residuals', also called
             'chisquare', is the WSSR between the data and your fitted
             function; ffiitt has minimized that.  At this stage, with
             weighted data, chisquare is expected to approach the num-
             ber of degrees of freedom (data points minus parameters).










   GNUPLOT 4.0                                                       36


             The WSSR can be used to calculate the reduced chisquare
             (WSSR/ndf) or stdfit, the standard deviation of the fit,
             sqrt(WSSR/ndf).  Both of these are reported for the final
             WSSR.

             If the data are unweighted, stdfit is the rms value of the
             deviation of the data from the fitted function, in user
             units.

             If you supplied valid data errors, the number of data
             points is large enough, and the model is correct, the
             reduced chisquare should be about unity.  (For details,
             look up the 'chi-squared distribution' in your favourite
             statistics reference.)  If so, there are additional tests,
             beyond the scope of this overview, for determining how
             well the model fits the data.

             A reduced chisquare much larger than 1.0 may be due to
             incorrect data error estimates, data errors not normally
             distributed, systematic measurement errors, 'outliers', or
             an incorrect model function.  A plot of the residuals,
             e.g., pplloott ''ddaattaaffiillee'' uussiinngg 11::(($$22--ff(($$11)))), may help to show
             any systematic trends.  Plotting both the data points and
             the function may help to suggest another model.

             Similarly, a reduced chisquare less than 1.0 indicates
             WSSR is less than that expected for a random sample from
             the function with normally distributed errors.  The data
             error estimates may be too large, the statistical assump-
             tions may not be justified, or the model function may be
             too general, fitting fluctuations in a particular sample
             in addition to the underlying trends.  In the latter case,
             a simpler function may be more appropriate.

             You'll have to get used to both ffiitt and the kind of prob-
             lems you apply it to before you can relate the standard
             errors to some more practical estimates of parameter
             uncertainties or evaluate the significance of the correla-
             tion matrix.

             Note that ffiitt, in common with most NLLS implementations,
             minimizes the weighted sum of squared distances (y-
             f(x))**2.  It does not provide any means to account for
             "errors" in the values of x, only in y.  Also, any "out-
             liers" (data points outside the normal distribution of the
             model) will have an exaggerated effect on the solution.



        2244..44..  FFiitt ccoonnttrroolllliinngg













   GNUPLOT 4.0                                                       37


        There are a number of ggnnuupplloott variables that can be defined to
        affect ffiitt.  Those which can be defined once ggnnuupplloott is running
        are listed under 'control_variables' while those defined before
        starting ggnnuupplloott are listed under 'environment_variables'.




             2244..44..11..  CCoonnttrrooll vvaarriiaabblleess


             The default epsilon limit (1e-5) may be changed by declar-
             ing a value for
                   FIT_LIMIT
             When the sum of squared residuals changes between two
             iteration steps by a factor less than this number
             (epsilon), the fit is considered to have 'converged'.

             The maximum number of iterations may be limited by declar-
             ing a value for
                   FIT_MAXITER
             A value of 0 (or not defining it at all)  means that there
             is no limit.

             If you need even more control about the algorithm, and
             know the Marquardt-Levenberg algorithm well, there are
             some more variables to influence it. The startup value of
             llaammbbddaa is normally calculated automatically from the ML-
             matrix, but if you want to, you may provide your own one
             with
                   FIT_START_LAMBDA
             Specifying FIT_START_LAMBDA as zero or less will re-enable
             the automatic selection. The variable
                   FIT_LAMBDA_FACTOR
             gives the factor by which llaammbbddaa is increased or decreased
             whenever the chi-squared target function increased or
             decreased significantly.  Setting FIT_LAMBDA_FACTOR to
             zero re-enables the default factor of 10.0.

             Other variables with the FIT_ prefix may be added to ffiitt,
             so it is safer not to use that prefix for user-defined
             variables.

             The variables FIT_SKIP and FIT_INDEX were used by earlier
             releases of ggnnuupplloott with a 'fit' patch called ggnnuuffiitt and
             are no longer available.  The datafile eevveerryy modifier pro-
             vides the functionality of FIT_SKIP.  FIT_INDEX was used
             for multi-branch fitting, but multi-branch fitting of one
             independent variable is now done as a pseudo-3D fit in
             which the second independent variable and uussiinngg are used
             to specify the branch.  See ffiitt mmuullttii--bbrraanncchh.












   GNUPLOT 4.0                                                       38


             2244..44..22..  EEnnvviirroonnmmeenntt vvaarriiaabblleess


             The environment variables must be defined before ggnnuupplloott
             is executed; how to do so depends on your operating sys-
             tem.

                   FIT_LOG
             changes the name (and/or path) of the file to which the
             fit log will be written from the default of "fit.log" in
             the working directory. The default value can be overwrit-
             ten using the command sseett ffiittllooggffiillee.

                   FIT_SCRIPT
             specifies a command that may be executed after an user
             interrupt. The default is rreepplloott, but a pplloott or llooaadd com-
             mand may be useful to display a plot customized to high-
             light the progress of the fit.



        2244..55..  MMuullttii--bbrraanncchh


        In multi-branch fitting, multiple data sets can be simultane-
        ously fit with functions of one independent variable having
        common parameters by minimizing the total WSSR.  The function
        and parameters (branch) for each data set are selected by using
        a 'pseudo-variable', e.g., either the dataline number (a 'col-
        umn' index of -1) or the datafile index (-2), as the second
        independent variable.

        Example:  Given two exponential decays of the form, z=f(x),
        each describing a different data set but having a common decay
        time, estimate the values of the parameters.  If the datafile
        has the format x:z:s, then
             f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
             fit f(x,y) 'datafile' using  1:-1:2:3  via a, b, tau

        For a more complicated example, see the file "hexa.fnc" used by
        the "fit.dem" demo.

        Appropriate weighting may be required since unit weights may
        cause one branch to predominate if there is a difference in the
        scale of the dependent variable.  Fitting each branch sepa-
        rately, using the multi-branch solution as initial values, may
        give an indication as to the relative effect of each branch on
        the joint solution.















   GNUPLOT 4.0                                                       39


        2244..66..  SSttaarrttiinngg vvaalluueess


        Nonlinear fitting is not guaranteed to converge to the global
        optimum (the solution with the smallest sum of squared residu-
        als, SSR), and can get stuck at a local minimum.  The routine
        has no way to determine that;  it is up to you to judge whether
        this has happened.

        ffiitt may, and often will get "lost" if started far from a solu-
        tion, where SSR is large and changing slowly as the parameters
        are varied, or it may reach a numerically unstable region
        (e.g., too large a number causing a floating point overflow)
        which results in an "undefined value" message or ggnnuupplloott halt-
        ing.

        To improve the chances of finding the global optimum, you
        should set the starting values at least roughly in the vicinity
        of the solution, e.g., within an order of magnitude, if possi-
        ble.  The closer your starting values are to the solution, the
        less chance of stopping at another minimum.  One way to find
        starting values is to plot data and the fitting function on the
        same graph and change parameter values and rreepplloott until reason-
        able similarity is reached.  The same plot is also useful to
        check whether the fit stopped at a minimum with a poor fit.

        Of course, a reasonably good fit is not proof there is not a
        "better" fit (in either a statistical sense, characterized by
        an improved goodness-of-fit criterion, or a physical sense,
        with a solution more consistent with the model.)  Depending on
        the problem, it may be desirable to ffiitt with various sets of
        starting values, covering a reasonable range for each parame-
        ter.



        2244..77..  TTiippss


        Here are some tips to keep in mind to get the most out of ffiitt.
        They're not very organized, so you'll have to read them several
        times until their essence has sunk in.

        The two forms of the vviiaa argument to ffiitt serve two largely dis-
        tinct purposes.  The vviiaa ""ffiillee"" form is best used for (possibly
        unattended) batch operation, where you just supply the startup
        values in a file and can later use uuppddaattee to copy the results
        back into another (or the same) parameter file.

        The vviiaa vvaarr11,, vvaarr22,, ...... form is best used interactively, where
        the command history mechanism may be used to edit the list of
        parameters to be fitted or to supply new startup values for the
        next try.  This is particularly useful for hard problems, where










   GNUPLOT 4.0                                                       40


        a direct fit to all parameters at once won't work without good
        starting values.  To find such, you can iterate several times,
        fitting only some of the parameters, until the values are close
        enough to the goal that the final fit to all parameters at once
        will work.

        Make sure that there is no mutual dependency among parameters
        of the function you are fitting.  For example, don't try to fit
        a*exp(x+b), because a*exp(x+b)=a*exp(b)*exp(x).  Instead, fit
        either a*exp(x) or exp(x+b).

        A technical issue:  the parameters must not be too different in
        magnitude.  The larger the ratio of the largest and the small-
        est absolute parameter values, the slower the fit will con-
        verge.  If the ratio is close to or above the inverse of the
        machine floating point precision, it may take next to forever
        to converge, or refuse to converge at all.  You will have to
        adapt your function to avoid this, e.g., replace 'parameter' by
        '1e9*parameter' in the function definition, and divide the
        starting value by 1e9.

        If you can write your function as a linear combination of sim-
        ple functions weighted by the parameters to be fitted, by all
        means do so.  That helps a lot, because the problem is no
        longer nonlinear and should converge with only a small number
        of iterations, perhaps just one.

        Some prescriptions for analysing data, given in practical
        experimentation courses, may have you first fit some functions
        to your data, perhaps in a multi-step process of accounting for
        several aspects of the underlying theory one by one, and then
        extract the information you really wanted from the fitting
        parameters of those functions.  With ffiitt, this may often be
        done in one step by writing the model function directly in
        terms of the desired parameters.  Transforming data can also
        quite often be avoided, though sometimes at the cost of a more
        difficult fit problem.  If you think this contradicts the pre-
        vious paragraph about simplifying the fit function, you are
        correct.

        A "singular matrix" message indicates that this implementation
        of the Marquardt-Levenberg algorithm can't calculate parameter
        values for the next iteration.  Try different starting values,
        writing the function in another form, or a simpler function.

        Finally, a nice quote from the manual of another fitting pack-
        age (fudgit), that kind of summarizes all these issues:  "Non-
        linear fitting is an art!"















   GNUPLOT 4.0                                                       41


   2255..  HHeellpp


   The hheellpp command displays on-line help. To specify information on a
   particular topic use the syntax:

         help {<topic>}

   If <topic> is not specified, a short message is printed about ggnnuu--
   pplloott.  After help for the requested topic is given, a menu of
   subtopics is given; help for a subtopic may be requested by typing
   its name, extending the help request.  After that subtopic has been
   printed, the request may be extended again or you may go back one
   level to the previous topic.  Eventually, the ggnnuupplloott command line
   will return.

   If a question mark (?) is given as the topic, the list of topics
   currently available is printed on the screen.



   2266..  HHiissttoorryy


   hhiissttoorryy command lists or saves previous entries in the history of
   the command line editing, or executes an entry.

   Here you find 'usage by examples':

         history               # show the complete history
         history 5             # show last 5 entries in the history
         history quiet 5       # show last 5 entries without entry num-
   bers
         history "hist.gp"     # write the complete history to file
   hist.gp
         history "hist.gp" append # append the complete history to file
   hist.gp
         history 10 "hist.gp"  # write last 10 commands to file hist.gp
         history 10 "|head -5 >>diary.gp" # write 5 history commands
   using pipe
         history ?load         # show all history entries starting with
   "load"
         history ?"set c"      # like above, several words enclosed in
   quotes
         hi !reread            # execute last entry starting with
   "reread"
         hist !"set xr"        # like above, several words enclosed in
   quotes
         hi !hi                # guess yourself :-))

   On systems which support a popen function (Unix), the output of his-
   tory can be piped through an external program by starting the file
   name with a '|', as one of the above examples demonstrates.










   GNUPLOT 4.0                                                       42


   2277..  IIff


   The iiff command allows commands to be executed conditionally.

   Syntax:
         if (<condition>) <command-line> [; else if (<condition>) ...;
   else ...]

   <condition> will be evaluated.  If it is true (non-zero), then the
   command(s) of the <command-line> will be executed.  If <condition>
   is false (zero), then the entire <command-line> is ignored until the
   next occurrence of eellssee.  Note that use of ;; to allow multiple com-
   mands on the same line will _not_ end the conditionalized commands.

   Examples:
         pi=3
         if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1); print pi
   will display:
         ?Fixing pi!
         3.14159265358979
   but
         if (1==2) print "Never see this"; print "Or this either"
   will not display anything.

   else:
         v=0
         v=v+1; if (v%2) print "2" ; else if (v%3) print "3"; else
   print "fred"
   (repeat the last line repeatedly!)

   See rreerreeaadd for an example of how iiff and rreerreeaadd can be used together
   to perform a loop.



   2288..  LLooaadd


   The llooaadd command executes each line of the specified input file as
   if it had been typed in interactively.  Files created by the ssaavvee
   command can later be llooaadded.  Any text file containing valid com-
   mands can be created and then executed by the llooaadd command.  Files
   being llooaadded may themselves contain llooaadd or ccaallll commands.  See ccoomm--
   mmeennttss for information about comments in commands.  To llooaadd with
   arguments, see ccaallll.

   The llooaadd command _must_ be the last command on a multi-command line.

   Syntax:
         load "<input-file>"

   The name of the input file must be enclosed in quotes.










   GNUPLOT 4.0                                                       43


   The special filename "-" may be used to llooaadd commands from standard
   input.  This allows a ggnnuupplloott command file to accept some commands
   from standard input.  Please see "help batch/interactive" for more
   details.

   On some systems which support a popen function (Unix), the load file
   can be read from a pipe by starting the file name with a '<'.

   Examples:
         load 'work.gnu'
         load "func.dat"
         load "< loadfile_generator.sh"

   The llooaadd command is performed implicitly on any file names given as
   arguments to ggnnuupplloott.  These are loaded in the order specified, and
   then ggnnuupplloott exits.



   2299..  PPaauussee


   The ppaauussee command displays any text associated with the command and
   then waits a specified amount of time or until the carriage return
   is pressed.  ppaauussee is especially useful in conjunction with llooaadd
   files.

   Syntax:
         pause <time> {"<string>"}
         pause mouse {"<string>"}

   <time> may be any constant or expression.  Choosing -1 will wait
   until a carriage return is hit, zero (0) won't pause at all, and a
   positive number will wait the specified number of seconds.  The time
   is rounded to an integer number of seconds if subsecond time resolu-
   tion is not supported by the given platform.  ppaauussee 00 is synonymous
   with pprriinntt.

   If the current terminal supports mousing, then ppaauussee mmoouussee will ter-
   minate on either a mouse click or on ctrl-C.  For all other termi-
   nals, or if mousing is not active, ppaauussee mmoouussee is equivalent to
   ppaauussee --11.

   Note: Since ppaauussee communicates with the operating system rather than
   the graphics, it may behave differently with different device driv-
   ers (depending upon how text and graphics are mixed).

   Examples:
         pause -1    # Wait until a carriage return is hit
         pause 3     # Wait three seconds
         pause -1  "Hit return to continue"
         pause 10  "Isn't this pretty?  It's a cubic spline."
         pause mouse "Click mouse on selected data point"










   GNUPLOT 4.0                                                       44


   3300..  PPlloott


   pplloott is the primary command for drawing plots with ggnnuupplloott.  It cre-
   ates plots of functions and data in many, many ways.  pplloott is used
   to draw 2-d functions and data; sspplloott draws 2-d projections of 3-d
   surfaces and data.  pplloott and sspplloott contain many common features; see
   sspplloott for differences.  Note specifically that sspplloott's bbiinnaarryy and
   mmaattrriixx options do not exist for pplloott, and pplloott's aaxxeess option does
   not exist for sspplloott.

   Syntax:
         plot {<ranges>}
              {<function> | {"<datafile>" {datafile-modifiers}}}
              {axes <axes>} {<title-spec>} {with <style>}
              {, {definitions,} <function> ...}

   where either a <function> or the name of a data file enclosed in
   quotes is supplied.  A function is a mathematical expression or a
   pair of mathematical expressions in parametric mode.  The expres-
   sions may be defined completely or in part earlier in the stream of
   ggnnuupplloott commands (see uusseerr--ddeeffiinneedd).

   It is also possible to define functions and parameters on the pplloott
   command itself.  This is done merely by isolating them from other
   items with commas.

   There are four possible sets of axes available; the keyword <axes>
   is used to select the axes for which a particular line should be
   scaled.  xx11yy11 refers to the axes on the bottom and left; xx22yy22 to
   those on the top and right; xx11yy22 to those on the bottom and right;
   and xx22yy11 to those on the top and left.  Ranges specified on the pplloott
   command apply only to the first set of axes (bottom left).

   Examples:
         plot sin(x)
         plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
         plot [t=1:10] [-pi:pi*2] tan(t), \
              "data.1" using (tan($2)):($3/$4) smooth csplines \
                       axes x1y2 notitle with lines 5

   See also sshhooww pplloott.




        3300..11..  DDaattaa--ffiillee


        Discrete data contained in a file can be displayed by specify-
        ing the name of the data file (enclosed in single or double
        quotes) on the pplloott command line.











   GNUPLOT 4.0                                                       45


        Syntax:
              plot '<file_name>' {index <index list>}
                                    {every <every list>}
                                    {thru <thru expression>}
                                    {using <using list>}
                                    {smooth <option>}

        The modifiers iinnddeexx, eevveerryy, tthhrruu, uussiinngg, and ssmmooootthh are dis-
        cussed separately.  In brief, iinnddeexx selects which data sets in
        a multi-data-set file are to be plotted, eevveerryy specifies which
        points within a single data set are to be plotted, uussiinngg deter-
        mines how the columns within a single record are to be inter-
        preted (tthhrruu is a special case of uussiinngg), and ssmmooootthh allows for
        simple interpolation and approximation.  (sspplloott has a similar
        syntax, but does not support the ssmmooootthh and tthhrruu options.)

        Data files should contain at least one data point per record
        (uussiinngg can select one data point from the record). Records
        beginning with ## (and also with !! on VMS) will be treated as
        comments and ignored.  Each data point represents an (x,y)
        pair. For ppllootts with error bars or error bars with lines (see
        sseett ssttyyllee eerrrroorrbbaarrss or sseett ssttyyllee eerrrroorrlliinneess), each data point
        is (x,y,ydelta), (x,y,ylow,yhigh), (x,y,xdelta),
        (x,y,xlow,xhigh), or (x,y,xlow,xhigh,ylow,yhigh).

        In all cases, the numbers of each record of a data file must be
        separated by white space (one or more blanks or tabs) unless a
        format specifier is provided by the uussiinngg option. This white
        space divides each record into columns. However, whitespace
        inside a pair of double quotes is ignored when counting col-
        umns, so the following datafile line has three columns:
              1.0 "second column" 3.0

        Data may be written in exponential format with the exponent
        preceded by the letter e, E, d, D, q, or Q.

        Only one column (the y value) need be provided.  If x is omit-
        ted, ggnnuupplloott provides integer values starting at 0.

        In datafiles, blank records (records with no characters other
        than blanks and a newline and/or carriage return) are signifi-
        cant---pairs of blank records separate iinnddeexxes (see pplloott
        ddaattaaffiillee iinnddeexx).  Data separated by double blank records are
        treated as if they were in separate data files.

        Single blank records designate discontinuities in a pplloott; no
        line will join points separated by a blank records (if they are
        plotted with a line style).

        If autoscaling has been enabled (sseett aauuttoossccaallee), the axes are
        automatically extended to include all datapoints, with a whole
        number of tic marks if tics are being drawn.  This has two con-
        sequences: i) For sspplloott, the corner of the surface may not










   GNUPLOT 4.0                                                       46


        coincide with the corner of the base.  In this case, no verti-
        cal line is drawn.  ii) When plotting data with the same x
        range on a dual-axis graph, the x coordinates may not coincide
        if the x2tics are not being drawn.  This is because the x axis
        has been autoextended to a whole number of tics, but the x2
        axis has not.  The following example illustrates the problem:

              reset; plot '-', '-' axes x2y1
              1 1
              19 19
              e
              1 1
              19 19
              e

        To avoid this, you can use the ffiixxmmiinn/ffiixxmmaaxx feature of the sseett
        aauuttoossccaallee command, which turns off the automatic extension of
        the axis range upto the next tic mark.




             3300..11..11..  EEvveerryy


             The eevveerryy keyword allows a periodic sampling of a data set
             to be plotted.

             In the discussion a "point" is a datum defined by a single
             record in the file; "block" here will mean the same thing
             as "datablock" (see gglloossssaarryy).

             Syntax:
                   plot 'file' every {<point_incr>}
                                       {:{<block_incr>}
                                         {:{<start_point>}
                                           {:{<start_block>}
                                             {:{<end_point>}
                                               {:<end_block>}}}}}

             The data points to be plotted are selected according to a
             loop from <ssttaarrtt__ppooiinntt> to <eenndd__ppooiinntt> with increment
             <ppooiinntt__iinnccrr> and the blocks according to a loop from
             <ssttaarrtt__bblloocckk> to <eenndd__bblloocckk> with increment <bblloocckk__iinnccrr>.

             The first datum in each block is numbered '0', as is the
             first block in the file.

             Note that records containing unplottable information are
             counted.

             Any of the numbers can be omitted; the increments default
             to unity, the start values to the first point or block,










   GNUPLOT 4.0                                                       47


             and the end values to the last point or block.  If eevveerryy
             is not specified, all points in all lines are plotted.

             Examples:
                   every :::3::3    # selects just the fourth block
             ('0' is first)
                   every :::::9     # selects the first 10 blocks
                   every 2:2        # selects every other point in
             every other block
                   every ::5::15    # selects points 5 through 15 in
             each block

             See , , and .



             3300..11..22..  EExxaammppllee ddaattaaffiillee


             This example plots the data in the file "population.dat"
             and a theoretical curve:

                   pop(x) = 103*exp((1965-x)/10)
                   plot [1960:1990] 'population.dat', pop(x)

             The file "population.dat" might contain:

                   # Gnu population in Antarctica since 1965
                      1965   103
                      1970   55
                      1975   34
                      1980   24
                      1985   10




             3300..11..33..  IInnddeexx


             The iinnddeexx keyword allows only some of the data sets in a
             multi-data-set file to be plotted.

             Syntax:
                   plot 'file' index <m>{{:<n>}:<p>}

             Data sets are separated by pairs of blank records.  iinnddeexx
             <<mm>> selects only set <m>; iinnddeexx <<mm>>::<<nn>> selects sets in
             the range <m> to <n>; and iinnddeexx <<mm>>::<<nn>>::<<pp>> selects
             indices <m>, <m>+<p>, <m>+2<p>, etc., but stopping at <n>.
             Following C indexing, the index 0 is assigned to the first
             data set in the file.  Specifying too large an index
             results in an error message.  If iinnddeexx is not specified,










   GNUPLOT 4.0                                                       48


             all sets are plotted as a single data set.

             Example:
                   plot 'file' index 4:5




             3300..11..44..  SSmmooootthh


             ggnnuupplloott includes a few general-purpose routines for inter-
             polation and approximation of data; these are grouped
             under the ssmmooootthh option.  More sophisticated data process-
             ing may be performed by preprocessing the data externally
             or by using ffiitt with an appropriate model.

             Syntax:
                   smooth {unique | frequency | csplines | acsplines |
             bezier | sbezier}

             uunniiqquuee and ffrreeqquueennccyy plot the data after making them mono-
             tonic.  Each of the other routines uses the data to deter-
             mine the coefficients of a continuous curve between the
             endpoints of the data.  This curve is then plotted in the
             same manner as a function, that is, by finding its value
             at uniform intervals along the abscissa (see sseett ssaammpplleess)
             and connecting these points with straight line segments
             (if a line style is chosen).

             If aauuttoossccaallee is in effect, the ranges will be computed
             such that the plotted curve lies within the borders of the
             graph.

             If aauuttoossccaallee is not in effect, and the smooth option is
             either aaccsspplliinnee or ccsspplliinnee, the sampling of the generated
             curve is done across the intersection of the x range cov-
             ered by the input data and the fixed abscissa range as
             defined by sseett xxrraannggee.

             If too few points are available to allow the selected
             option to be applied, an error message is produced.  The
             minimum number is one for uunniiqquuee and ffrreeqquueennccyy, four for
             aaccsspplliinneess, and three for the others.

             The ssmmooootthh options have no effect on function plots.

















   GNUPLOT 4.0                                                       49


                  3300..11..44..11..  AAccsspplliinneess


                  The aaccsspplliinneess option approximates the data with a
                  "natural smoothing spline".  After the data are made
                  monotonic in x (see ssmmooootthh uunniiqquuee), a curve is piece-
                  wise constructed from segments of cubic polynomials
                  whose coefficients are found by the weighting the
                  data points; the weights are taken from the third
                  column in the data file.  That default can be modi-
                  fied by the third entry in the uussiinngg list, e.g.,
                        plot 'data-file' using 1:2:(1.0) smooth
                  acsplines

                  Qualitatively, the absolute magnitude of the weights
                  determines the number of segments used to construct
                  the curve.  If the weights are large, the effect of
                  each datum is large and the curve approaches that
                  produced by connecting consecutive points with natu-
                  ral cubic splines.  If the weights are small, the
                  curve is composed of fewer segments and thus is
                  smoother; the limiting case is the single segment
                  produced by a weighted linear least squares fit to
                  all the data.  The smoothing weight can be expressed
                  in terms of errors as a statistical weight for a
                  point divided by a "smoothing factor" for the curve
                  so that (standard) errors in the file can be used as
                  smoothing weights.

                  Example:
                        sw(x,S)=1/(x*x*S)
                        plot 'data_file' using 1:2:(sw($3,100)) smooth
                  acsplines



                  3300..11..44..22..  BBeezziieerr


                  The bbeezziieerr option approximates the data with a Bezier
                  curve of degree n (the number of data points) that
                  connects the endpoints.



                  3300..11..44..33..  CCsspplliinneess


                  The ccsspplliinneess option connects consecutive points by
                  natural cubic splines after rendering the data mono-
                  tonic (see ssmmooootthh uunniiqquuee).












   GNUPLOT 4.0                                                       50


                  3300..11..44..44..  SSbbeezziieerr


                  The ssbbeezziieerr option first renders the data monotonic
                  (uunniiqquuee) and then applies the bbeezziieerr algorithm.



                  3300..11..44..55..  UUnniiqquuee


                  The uunniiqquuee option makes the data monotonic in x;
                  points with the same x-value are replaced by a single
                  point having the average y-value.  The resulting
                  points are then connected by straight line segments.
                  demos



                  3300..11..44..66..  FFrreeqquueennccyy


                  The ffrreeqquueennccyy option makes the data monotonic in x;
                  points with the same x-value are replaced by a single
                  point having the summed y-values.  The resulting
                  points are then connected by straight line segments.



             3300..11..55..  SSppeecciiaall--ffiilleennaammeess


             A special filename of ''--'' specifies that the data are
             inline; i.e., they follow the command.  Only the data fol-
             low the command; pplloott options like filters, titles, and
             line styles remain on the pplloott command line.  This is sim-
             ilar to << in unix shell script, and $DECK in VMS DCL.
             The data are entered as though they are being read from a
             file, one data point per record.  The letter "e" at the
             start of the first column terminates data entry.  The
             uussiinngg option can be applied to these data---using it to
             filter them through a function might make sense, but
             selecting columns probably doesn't!

             ''--'' is intended for situations where it is useful to have
             data and commands together, e.g., when ggnnuupplloott is run as a
             sub-process of some front-end application.  Some of the
             demos, for example, might use this feature.  While pplloott
             options such as iinnddeexx and eevveerryy are recognized, their use
             forces you to enter data that won't be used.  For example,
             while

                   plot '-' index 0, '-' index 1










   GNUPLOT 4.0                                                       51


                   2
                   4
                   6


                   10
                   12
                   14
                   e
                   2
                   4
                   6


                   10
                   12
                   14
                   e

             does indeed work,

                   plot '-', '-'
                   2
                   4
                   6
                   e
                   10
                   12
                   14
                   e

             is a lot easier to type.

             If you use ''--'' with rreepplloott, you may need to enter the data
             more than once (see rreepplloott).

             A blank filename ('') specifies that the previous filename
             should be reused.  This can be useful with things like

                   plot 'a/very/long/filename' using 1:2, '' using 1:3,
             '' using 1:4

             (If you use both ''--'' and '''' on the same pplloott command,
             you'll need to have two sets of inline data, as in the
             example above.)

             On some computer systems with a popen function (Unix), the
             datafile can be piped through a shell command by starting
             the file name with a '<'.  For example,

                   pop(x) = 103*exp(-x/10)
                   plot "< awk '{print $1-1965, $2}' population.dat",
             pop(x)










   GNUPLOT 4.0                                                       52


             would plot the same information as the first population
             example but with years since 1965 as the x axis.  If you
             want to execute this example, you have to delete all com-
             ments from the data file above or substitute the following
             command for the first part of the command above (the part
             up to the comma):

                   plot "< awk '$0 !~ /^#/ {print $1-1965, $2}' popula-
             tion.dat"

             While this approach is most flexible, it is possible to
             achieve simple filtering with the uussiinngg or tthhrruu keywords.



             3300..11..66..  TThhrruu


             The tthhrruu function is provided for backward compatibility.

             Syntax:
                   plot 'file' thru f(x)

             It is equivalent to:

                   plot 'file' using 1:(f($2))

             While the latter appears more complex, it is much more
             flexible.  The more natural

                   plot 'file' thru f(y)

             also works (i.e. you can use y as the dummy variable).

             tthhrruu is parsed for sspplloott and ffiitt but has no effect.



             3300..11..77..  UUssiinngg


             The most common datafile modifier is uussiinngg.

             Syntax:
                   plot 'file' using {<entry> {:<entry> {:<entry>
             ...}}} {'format'}

             If a format is specified, each datafile record is read
             using the C library's 'scanf' function, with the specified
             format string.  Otherwise the record is read and broken
             into columns at spaces or tabs.  A format cannot be speci-
             fied if time-format data is being used (this must be done
             by sseett ddaattaa ttiimmee).










   GNUPLOT 4.0                                                       53


             The resulting array of data is then sorted into columns
             according to the entries.  Each <entry> may be a simple
             column number, which selects the datum, an expression
             enclosed in parentheses, or empty.  The expression can use
             $1 to access the first item read, $2 for the second item,
             and so on.  It can also use ccoolluummnn((xx)) and vvaalliidd((xx)) where x
             is an arbitrary expression resulting in an integer.  ccooll--
             uummnn((xx)) returns the x'th datum; vvaalliidd((xx)) tests that the
             datum in the x'th column is a valid number.  A column num-
             ber of 0 generates a number increasing (from zero) with
             each point, and is reset upon encountering two blank
             records.  A column number of -1 gives the dataline number,
             which starts at 0, increments at single blank records, and
             is reset at double blank records.  A column number of -2
             gives the index number, which is incremented only when two
             blank records are found.  An empty <entry> will default to
             its order in the list of entries.  For example, uussiinngg ::::44
             is interpreted as uussiinngg 11::22::44.

             N.B.---the ccaallll command also uses $'s as a special charac-
             ter.  See ccaallll for details about how to include a column
             number in a ccaallll argument list.

             If the uussiinngg list has but a single entry, that <entry>
             will be used for y and the data point number is used for
             x; for example, "pplloott ''ffiillee'' uussiinngg 11" is identical to
             "pplloott ''ffiillee'' uussiinngg 00::11".  If the uussiinngg list has two
             entries, these will be used for x and y.  Additional
             entries are usually errors in x and/or y.  See sseett ssttyyllee
             for details about plotting styles that make use of error
             information, and ffiitt for use of error information in curve
             fitting.

             'scanf' accepts several numerical specifications but ggnnuu--
             pplloott requires all inputs to be double-precision floating-
             point variables, so llff is the only permissible specifier.
             'scanf' expects to see white space---a blank, tab ("\t"),
             newline ("\n"), or formfeed ("\f")---between numbers; any-
             thing else in the input stream must be explicitly skipped.

             Note that the use of "\t", "\n", or "\f" requires use of
             double-quotes rather than single-quotes.

             Examples:

             This creates a plot of the sum of the 2nd and 3rd data
             against the first: The format string specifies comma-
             rather than space-separated columns.  The same result
             could be achieved by specifying sseett ddaattaaffiillee sseeppaarraattoorr
             "",,"".
                   plot 'file' using 1:($2+$3) '%lf,%lf,%lf'

             In this example the data are read from the file "MyData"










   GNUPLOT 4.0                                                       54


             using a more complicated format:
                   plot 'MyData' using "%*lf%lf%*20[^\n]%lf"

             The meaning of this format is:

                   %*lf        ignore a number
                   %lf         read a double-precision number (x by
             default)
                   %*20[^\n]   ignore 20 non-newline characters
                   %lf         read a double-precision number (y by
             default)

             One trick is to use the ternary ??:: operator to filter
             data:

                   plot 'file' using 1:($3>10 ? $2 : 1/0)

             which plots the datum in column two against that in column
             one provided the datum in column three exceeds ten.  11//00
             is undefined; ggnnuupplloott quietly ignores undefined points, so
             unsuitable points are suppressed.

             In fact, you can use a constant expression for the column
             number, provided it doesn't start with an opening paren-
             thesis; constructs like uussiinngg 00++((ccoommpplliiccaatteedd eexxpprreessssiioonn))
             can be used.  The crucial point is that the expression is
             evaluated once if it doesn't start with a left parenthe-
             sis, or once for each data point read if it does.

             If timeseries data are being used, the time can span mul-
             tiple columns.  The starting column should be specified.
             Note that the spaces within the time must be included when
             calculating starting columns for other data.  E.g., if the
             first element on a line is a time with an embedded space,
             the y value should be specified as column three.

             It should be noted that pplloott ''ffiillee'', pplloott ''ffiillee'' uussiinngg
             11::22, and pplloott ''ffiillee'' uussiinngg (($$11))::(($$22)) can be subtly differ-
             ent: 1) if ffiillee has some lines with one column and some
             with two, the first will invent x values when they are
             missing, the second will quietly ignore the lines with one
             column, and the third will store an undefined value for
             lines with one point (so that in a plot with lines, no
             line joins points across the bad point); 2) if a line con-
             tains text at the first column, the first will abort the
             plot on an error, but the second and third should quietly
             skip the garbage.

             In fact, it is often possible to plot a file with lots of
             lines of garbage at the top simply by specifying

                   plot 'file' using 1:2











   GNUPLOT 4.0                                                       55


             However, if you want to leave text in your data files, it
             is safer to put the comment character (#) in the first
             column of the text lines.  Feeble using demos.



        3300..22..  EErrrroorrbbaarrss


        Error bars are supported for 2-d data file plots by reading one
        to four additional columns (or uussiinngg entries); these additional
        values are used in different ways by the various errorbar
        styles.

        In the default situation, ggnnuupplloott expects to see three, four,
        or six numbers on each line of the data file---either

              (x, y, ydelta),
              (x, y, ylow, yhigh),
              (x, y, xdelta),
              (x, y, xlow, xhigh),
              (x, y, xdelta, ydelta), or
              (x, y, xlow, xhigh, ylow, yhigh).

        The x coordinate must be specified.  The order of the numbers
        must be exactly as given above, though the uussiinngg qualifier can
        manipulate the order and provide values for missing columns.
        For example,

              plot 'file' with errorbars
              plot 'file' using 1:2:(sqrt($1)) with xerrorbars
              plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerror-
        bars

        The last example is for a file containing an unsupported combi-
        nation of relative x and absolute y errors.  The uussiinngg entry
        generates absolute x min and max from the relative error.

        The y error bar is a vertical line plotted from (x, ylow) to
        (x, yhigh). If ydelta is specified instead of ylow and yhigh,
        ylow = y - ydelta and yhigh = y + ydelta are derived. If there
        are only two numbers on the record, yhigh and ylow are both set
        to y. The x error bar is a horizontal line computed in the same
        fashion. To get lines plotted between the data points, pplloott the
        data file twice, once with errorbars and once with lines (but
        remember to use the nnoottiittllee option on one to avoid two entries
        in the key). Alternately, use the errorlines command (see
        eerrrroorrlliinneess).

        The error bars have crossbars at each end unless sseett bbaarrss is
        used (see sseett bbaarrss for details).

        If autoscaling is on, the ranges will be adjusted to include










   GNUPLOT 4.0                                                       56


        the error bars.  See also errorbar demos.

        See pplloott uussiinngg, pplloott wwiitthh, and sseett ssttyyllee for more information.



        3300..33..  EErrrroorrlliinneess


        Lines with error bars are supported for 2-d data file plots by
        reading one to four additional columns (or uussiinngg entries);
        these additional values are used in different ways by the vari-
        ous errorlines styles.

        In the default situation, ggnnuupplloott expects to see three, four,
        or six numbers on each line of the data file---either

              (x, y, ydelta),
              (x, y, ylow, yhigh),
              (x, y, xdelta),
              (x, y, xlow, xhigh),
              (x, y, xdelta, ydelta), or
              (x, y, xlow, xhigh, ylow, yhigh).

        The x coordinate must be specified. The order of the numbers
        must be exactly as given above, though the uussiinngg qualifier can
        manipulate the order and provide values for missing columns.
        For example,

              plot 'file' with errorlines
              plot 'file' using 1:2:(sqrt($1)) with xerrorlines
              plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerror-
        lines

        The last example is for a file containing an unsupported combi-
        nation of relative x and absolute y errors. The uussiinngg entry
        generates absolute x min and max from the relative error.

        The y error bar is a vertical line plotted from (x, ylow) to
        (x, yhigh). If ydelta is specified instead of ylow and yhigh,
        ylow = y - ydelta and yhigh = y + ydelta are derived. If there
        are only two numbers on the record, yhigh and ylow are both set
        to y. The x error bar is a horizontal line computed in the same
        fashion.

        The error bars have crossbars at each end unless sseett bbaarrss is
        used (see sseett bbaarrss for details).

        If autoscaling is on, the ranges will be adjusted to include
        the error bars.

        See pplloott uussiinngg, pplloott wwiitthh, and sseett ssttyyllee for more information.











   GNUPLOT 4.0                                                       57


        3300..44..  PPaarraammeettrriicc


        When in parametric mode (sseett ppaarraammeettrriicc) mathematical expres-
        sions must be given in pairs for pplloott and in triplets for
        sspplloott.

        Examples:
              plot sin(t),t**2
              splot cos(u)*cos(v),cos(u)*sin(v),sin(u)

        Data files are plotted as before, except any preceding paramet-
        ric function must be fully specified before a data file is
        given as a plot.  In other words, the x parametric function
        (ssiinn((tt)) above) and the y parametric function (tt****22 above) must
        not be interrupted with any modifiers or data functions; doing
        so will generate a syntax error stating that the parametric
        function is not fully specified.

        Other modifiers, such as wwiitthh and ttiittllee, may be specified only
        after the parametric function has been completed:

              plot sin(t),t**2 title 'Parametric example' with lines-
        points

        See also Parametric Mode Demos.



        3300..55..  RRaannggeess


        The optional ranges specify the region of the graph that will
        be displayed.

        Syntax:
              [{<dummy-var>=}{{<min>}:{<max>}}]
              [{{<min>}:{<max>}}]

        The first form applies to the independent variable (xxrraannggee or
        ttrraannggee, if in parametric mode).  The second form applies to the
        dependent variable yyrraannggee (and xxrraannggee, too, if in parametric
        mode).  <dummy-var> is a new name for the independent variable.
        (The defaults may be changed with sseett dduummmmyy.)  The optional
        <min> and <max> terms can be constant expressions or *.

        In non-parametric mode, the order in which ranges must be given
        is xxrraannggee and yyrraannggee.

        In parametric mode, the order for the pplloott command is ttrraannggee,
        xxrraannggee, and yyrraannggee.  The following pplloott command shows setting
        the ttrraannggee to [-pi:pi], the xxrraannggee to [-1.3:1.3] and the yyrraannggee
        to [-1:1] for the duration of the graph:










   GNUPLOT 4.0                                                       58


              plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2

        Note that the x2range and y2range cannot be specified
        here---sseett xx22rraannggee and sseett yy22rraannggee must be used.

        Ranges are interpreted in the order listed above for the appro-
        priate mode.  Once all those needed are specified, no further
        ones must be listed, but unneeded ones cannot be skipped---use
        an empty range [[]] as a placeholder.

        ** can be used to allow autoscaling of either of min and max.
        See also sseett aauuttoossccaallee.

        Ranges specified on the pplloott or sspplloott command line affect only
        that graph; use the sseett xxrraannggee, sseett yyrraannggee, etc., commands to
        change the default ranges for future graphs.

        With time data, you must provide the range (in the same manner
        as the time appears in the datafile) within quotes.  ggnnuupplloott
        uses the ttiimmeeffmmtt string to read the value---see sseett ttiimmeeffmmtt.

        Examples:

        This uses the current ranges:
              plot cos(x)

        This sets the x range only:
              plot [-10:30] sin(pi*x)/(pi*x)

        This is the same, but uses t as the dummy-variable:
              plot [t = -10 :30]  sin(pi*t)/(pi*t)

        This sets both the x and y ranges:
              plot [-pi:pi] [-3:3]  tan(x), 1/x

        This sets only the y range, and turns off autoscaling on both
        axes:
              plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)

        This sets xmax and ymin only:
              plot [:200] [-pi:]  exp(sin(x))

        This sets the x range for a timeseries:
              set timefmt "%d/%m/%y %H:%M"
              plot ["1/6/93 12:00":"5/6/93 12:00"] 'timedata.dat'

        See also ranges demo.
















   GNUPLOT 4.0                                                       59


        3300..66..  TTiittllee


        A line title for each function and data set appears in the key,
        accompanied by a sample of the line and/or symbol used to rep-
        resent it.  It can be changed by using the ttiittllee option.

        Syntax:
              title "<title>" | notitle

        where <title> is the new title of the line and must be enclosed
        in quotes.  The quotes will not be shown in the key.  A special
        character may be given as a backslash followed by its octal
        value ("\345").  The tab character "\t" is understood.  Note
        that backslash processing occurs only for strings enclosed in
        double quotes---use single quotes to prevent such processing.
        The newline character "\n" is not processed in key entries in
        either type of string.

        The line title and sample can be omitted from the key by using
        the keyword nnoottiittllee.  A null title (ttiittllee '''') is equivalent to
        nnoottiittllee.  If only the sample is wanted, use one or more blanks
        (ttiittllee '' '').

        If kkeeyy aauuttoottiittlleess is set (which is the default) and neither
        ttiittllee nor nnoottiittllee are specified the line title is the function
        name or the file name as it appears on the pplloott command.  If it
        is a file name, any datafile modifiers specified will be
        included in the default title.

        The layout of the key itself (position, title justification,
        etc.) can be controlled by sseett kkeeyy.  Please see sseett kkeeyy for
        details.

        Examples:

        This plots y=x with the title 'x':
              plot x

        This plots x squared with title "x^2" and file "data.1" with
        title "measured data":
              plot x**2 title "x^2", 'data.1' t "measured data"

        This puts an untitled circular border around a polar graph:
              set polar; plot my_function(t), 1 notitle



        3300..77..  WWiitthh


        Functions and data may be displayed in one of a large number of
        styles.  The wwiitthh keyword provides the means of selection.










   GNUPLOT 4.0                                                       60


        Syntax:
              with <style> { {linestyle | ls <line_style>}
                             | {{linetype  | lt <line_type>}
                                {linewidth | lw <line_width>}
                                {pointtype | pt <point_type>}
                                {pointsize | ps <point_size>}
                                {fill | fs <fillstyle>}
                                {palette}}
                           }

        where <style> is either lliinneess, ppooiinnttss, lliinneessppooiinnttss, iimmppuullsseess,
        ddoottss, sstteeppss, ffsstteeppss, hhiisstteeppss, eerrrroorrbbaarrss, xxeerrrroorrbbaarrss, yyeerrrroorr--
        bbaarrss, xxyyeerrrroorrbbaarrss, eerrrroorrlliinneess, xxeerrrroorrlliinneess, yyeerrrroorrlliinneess, xxyyeerr--
        rroorrlliinneess, bbooxxeess, ffiilllleeddccuurrvveess, bbooxxeerrrroorrbbaarrss, bbooxxxxyyeerrrroorrbbaarrss,
        ffiinnaanncceebbaarrss, ccaannddlleessttiicckkss, vveeccttoorrss or ppmm33dd. Some of these
        styles require additional information. See pplloottttiinngg ssttyylleess for
        details of each style.  ffiillll is relevant only to certain 2D
        plots (currently bbooxxeess bbooxxxxyyeerrrroorrbbaarrss and ccaannddlleessttiicckkss).  Note
        that ffiilllleeddccuurrvveess and ppmm33dd can take an additional option not
        listed above (the latter only when used in the sspplloott com-
        mand)---see their help or examples below for more details.

        Default styles are chosen with the sseett ssttyyllee ffuunnccttiioonn and sseett
        ssttyyllee ddaattaa commands.

        By default, each function and data file will use a different
        line type and point type, up to the maximum number of available
        types.  All terminal drivers support at least six different
        point types, and re-use them, in order, if more are required.
        The LaTeX driver supplies an additional six point types (all
        variants of a circle), and thus will only repeat after 12
        curves are plotted with points.  The PostScript drivers (ppoosstt--
        ssccrriipptt) supplies a total of 64.

        If you wish to choose the line or point type for a single plot,
        <line_type> and <point_type> may be specified.  These are posi-
        tive integer constants (or expressions) that specify the line
        type and point type to be used for the plot.  Use tteesstt to dis-
        play the types available for your terminal.

        You may also scale the line width and point size for a plot by
        using <line_width> and <point_size>, which are specified rela-
        tive to the default values for each terminal.  The pointsize
        may also be altered globally---see sseett ppooiinnttssiizzee for details.
        But note that both <point_size> as set here and  as set by sseett
        ppooiinnttssiizzee multiply the default point size---their effects are
        not cumulative.  That is, sseett ppooiinnttssiizzee 22;; pplloott xx ww pp ppss 33 will
        use points three times default size, not six.

        If you have defined specific line type/width and point
        type/size combinations with sseett ssttyyllee lliinnee, one of these may be
        selected by setting <line_style> to the index of the desired
        style.










   GNUPLOT 4.0                                                       61


        If gnuplot was built with ppmm33dd support, the special keyword
        ppaalleettttee is allowed for smooth color change of lines, points and
        dots in sspplloottss. The color is chosen from a smooth palette which
        was set previously with the command sseett ppaalleettttee. The color
        value corresponds to the z-value of the point coordinates or to
        the color coordinate if specified by the 4th parameter in
        uussiinngg. The 2d pplloott command ignores this option.

        The keywords may be abbreviated as indicated.

        Note that the lliinneewwiiddtthh, ppooiinnttssiizzee and ppaalleettttee options are not
        supported by all terminals.

        Examples:

        This plots sin(x) with impulses:
              plot sin(x) with impulses

        This plots x with points, x**2 with the default:
              plot x w points, x**2

        This plots tan(x) with the default function style, file
        "data.1" with lines:
              plot [ ] [-2:5] tan(x), 'data.1' with l

        This plots "leastsq.dat" with impulses:
              plot 'leastsq.dat' w i

        This plots the data file "population" with boxes:
              plot 'population' with boxes

        This plots "exper.dat" with errorbars and lines connecting the
        points (errorbars require three or four columns):
              plot 'exper.dat' w lines, 'exper.dat' notitle w errorbars

        Another way to plot "exper.dat" with errorlines (errorbars
        require three or four columns):
              plot 'exper.dat' w errorlines

        This plots sin(x) and cos(x) with linespoints, using the same
        line type but different point types:
              plot sin(x) with linesp lt 1 pt 3, cos(x) with linesp lt
        1 pt 4

        This plots file "data" with points of type 3 and twice usual
        size:
              plot 'data' with points pointtype 3 pointsize 2

        This plots two data sets with lines differing only by weight:
              plot 'd1' t "good" w l lt 2 lw 3, 'd2' t "bad" w l lt 2
        lw 1

        This plots filled curve of x*x and a color stripe:










   GNUPLOT 4.0                                                       62


              plot x*x with filledcurve closed, 40 with filledcurve
        y1=10

        This plots x*x and a color box:
              plot x*x, (x>=-5 && x<=5 ? 40 : 1/0) with filledcurve
        y1=10 lt 8

        This plots a surface with color lines:
              splot x*x-y*y with line palette

        This plots two color surfaces at different altitudes:
              splot x*x-y*y with pm3d, x*x+y*y with pm3d at t

        See sseett ssttyyllee to change the default styles. See also styles
        demos.



   3311..  PPrriinntt


   The pprriinntt command prints the value of <expression> to the screen.
   It is synonymous with ppaauussee 00.  <expression> may be anything that
   ggnnuupplloott can evaluate that produces a number, or it can be a string.

   Syntax:
         print <expression> {, <expression>, ...}

   See eexxpprreessssiioonnss.  The output file can be set with sseett pprriinntt.



   3322..  PPwwdd


   The ppwwdd command prints the name of the working directory to the
   screen.



   3333..  QQuuiitt


   The eexxiitt and qquuiitt commands and END-OF-FILE character will exit ggnnuu--
   pplloott.  Each of these commands will clear the output device (as does
   the cclleeaarr command) before exiting.



   3344..  RReepplloott













   GNUPLOT 4.0                                                       63


   The rreepplloott command without arguments repeats the last pplloott or sspplloott
   command.  This can be useful for viewing a plot with different sseett
   options, or when generating the same plot for several devices.

   Arguments specified after a rreepplloott command will be added onto the
   last pplloott or sspplloott command (with an implied ',' separator) before it
   is repeated.  rreepplloott accepts the same arguments as the pplloott and
   sspplloott commands except that ranges cannot be specified.  Thus you can
   use rreepplloott to plot a function against the second axes if the previ-
   ous command was pplloott but not if it was sspplloott, and similarly you can
   use rreepplloott to add a plot from a binary file only if the previous
   command was sspplloott.

   N.B.---use of

         plot '-' ; ... ; replot

   is not recommended.  ggnnuupplloott does not store the inline data inter-
   nally, so since rreepplloott appends new information to the previous pplloott
   and then executes the modified command, the ''--'' from the initial
   pplloott will expect to read inline data again.

   Note that rreepplloott does not work in mmuullttiipplloott mode, since it repro-
   duces only the last plot rather than the entire screen.

   See also ccoommmmaanndd--lliinnee--eeddiittiinngg for ways to edit the last pplloott (sspplloott)
   command.

   See also sshhooww pplloott to show the whole current plotting command, and
   the possibility to copy it into the hhiissttoorryy.



   3355..  RReerreeaadd


   The rreerreeaadd command causes the current ggnnuupplloott command file, as spec-
   ified by a llooaadd command or on the command line, to be reset to its
   starting point before further commands are read from it.  This
   essentially implements an endless loop of the commands from the
   beginning of the command file to the rreerreeaadd command.  (But this is
   not necessarily a disaster---rreerreeaadd can be very useful when used in
   conjunction with iiff.  See iiff for details.)  The rreerreeaadd command has
   no effect if input from standard input.

   Examples:

   Suppose the file "looper" contains the commands
         a=a+1
         plot sin(x*a)
         pause -1
         if(a<5) reread
   and from within ggnnuupplloott you submit the commands










   GNUPLOT 4.0                                                       64


         a=0
         load 'looper'
   The result will be four plots (separated by the ppaauussee message).

   Suppose the file "data" contains six columns of numbers with a total
   yrange from 0 to 10; the first is x and the next are five different
   functions of x.  Suppose also that the file "plotter" contains the
   commands
         c_p = c_p+1
         plot "$0" using 1:c_p with lines linetype c_p
         if(c_p <  n_p) reread
   and from within ggnnuupplloott you submit the commands
         n_p=6
         c_p=1
         unset key
         set yrange [0:10]
         set multiplot
         call 'plotter' 'data'
         unset multiplot
   The result is a single graph consisting of five plots.  The yrange
   must be set explicitly to guarantee that the five separate graphs
   (drawn on top of each other in multiplot mode) will have exactly the
   same axes.  The linetype must be specified; otherwise all the plots
   would be drawn with the same type.  See also Reread Animation Demo
   (animate.dem).



   3366..  RReesseett


   The rreesseett command causes all graph-related options that can be set
   with the sseett command to take on their default values.  This command
   is useful, e.g., to restore the default graph settings at the end of
   a command file, or to return to a defined state after lots of set-
   tings have been changed within a command file.  Please refer to the
   sseett command to see the default values that the various options take.

   The following sseett commands do not change the graph status and are
   thus left unchanged: the terminal set with sseett tteerrmm, the output file
   set with sseett oouuttppuutt and directory paths set with sseett llooaaddppaatthh and
   sseett ffoonnttppaatthh.



   3377..  SSaavvee


   The ssaavvee command saves user-defined functions, variables, the sseett
   tteerrmm status, all sseett options, or all of these, plus the last pplloott
   (sspplloott) command to the specified file.

   Syntax:










   GNUPLOT 4.0                                                       65


         save  {<option>} '<filename>'

   where <option> is ffuunnccttiioonnss, vvaarriiaabblleess, tteerrmmiinnaall or sseett. If no
   option is used, ggnnuupplloott saves functions, variables, sseett options and
   the last pplloott (sspplloott) command.

   ssaavveed files are written in text format and may be read by the llooaadd
   command. For ssaavvee with the sseett option or without any option, the
   tteerrmmiinnaall choice and the oouuttppuutt filename are written out as a com-
   ment, to get an output file that works in other installations of
   gnuplot, without changes and without risk of unwillingly overwriting
   files.

   ssaavvee tteerrmmiinnaall will write out just the tteerrmmiinnaall status, without the
   comment marker in front of it. This is mainly useful for switching
   the tteerrmmiinnaall setting for a short while, and getting back to the pre-
   viously set terminal, afterwards, by loading the saved tteerrmmiinnaall sta-
   tus. Note that for a single gnuplot session you may rather use the
   other method of saving and restoring current terminal by the com-
   mands sseett tteerrmm ppuusshh and sseett tteerrmm ppoopp, see sseett tteerrmm.

   The filename must be enclosed in quotes.

   The special filename "-" may be used to ssaavvee commands to standard
   output.  On systems which support a popen function (Unix), the out-
   put of save can be piped through an external program by starting the
   file name with a '|'.  This provides a consistent interface to ggnnuu--
   pplloott's internal settings to programs which communicate with ggnnuupplloott
   through a pipe.  Please see "help batch/interactive" for more
   details.

   Examples:
         save 'work.gnu'
         save functions 'func.dat'
         save var 'var.dat'
         save set 'options.dat'
         save term 'myterm.gnu'
         save '-'
         save '|grep title >t.gp'



   3388..  SSeett--sshhooww


   The sseett command can be used to set _lots_ of options.  No screen is
   drawn, however, until a pplloott, sspplloott, or rreepplloott command is given.

   The sshhooww command shows their settings;  sshhooww aallll shows all the set-
   tings.

   Options changed using sseett can be returned to the default state by
   giving the corresponding uunnsseett command.  See also the rreesseett command,










   GNUPLOT 4.0                                                       66


   which returns all settable parameters to default values.

   If a variable contains time/date data, sshhooww will display it accord-
   ing to the format currently defined by sseett ttiimmeeffmmtt, even if that was
   not in effect when the variable was initially defined.




        3388..11..  AAnngglleess


        By default, ggnnuupplloott assumes the independent variable in polar
        graphs is in units of radians.  If sseett aanngglleess ddeeggrreeeess is speci-
        fied before sseett ppoollaarr, then the default range is [0:360] and
        the independent variable has units of degrees.  This is partic-
        ularly useful for plots of data files.  The angle setting also
        applies to 3-d mapping as set via the sseett mmaappppiinngg command.

        Syntax:
              set angles {degrees | radians}
              show angles

        The angle specified in sseett ggrriidd ppoollaarr is also read and dis-
        played in the units specified by sseett aanngglleess.

        sseett aanngglleess also affects the arguments of the machine-defined
        functions sin(x), cos(x) and tan(x), and the outputs of
        asin(x), acos(x), atan(x), atan2(x), and arg(x).  It has no
        effect on the arguments of hyperbolic functions or Bessel func-
        tions.  However, the output arguments of inverse hyperbolic
        functions of complex arguments are affected; if these functions
        are used, sseett aanngglleess rraaddiiaannss must be in effect to maintain con-
        sistency between input and output arguments.

              x={1.0,0.1}
              set angles radians
              y=sinh(x)
              print y         #prints {1.16933, 0.154051}
              print asinh(y)  #prints {1.0, 0.1}
        but
              set angles degrees
              y=sinh(x)
              print y         #prints {1.16933, 0.154051}
              print asinh(y)  #prints {57.29578, 5.729578}
        See also poldat.dem: polar plot using sseett aanngglleess demo.



        3388..22..  AArrrrooww













   GNUPLOT 4.0                                                       67


        Arbitrary arrows can be placed on a plot using the sseett aarrrrooww
        command.

        Syntax:
              set arrow {<tag>} {from <position>} {to|rto <position>}
                        { {arrowstyle | as <arrow_style>}
                          | {nohead | head | heads}
                            {size <length>,<angle>}
                            {filled | nofilled}
                            {front | back}
                            { {linestyle | ls <line_style>}
                              | {linetype | lt <line_type>}
                                {linewidth | lw <line_width} } }
              unset arrow {<tag>}
              show arrow {<tag>}

        <tag> is an integer that identifies the arrow.  If no tag is
        given, the lowest unused tag value is assigned automatically.
        The tag can be used to delete or change a specific arrow.  To
        change any attribute of an existing arrow, use the sseett aarrrrooww
        command with the appropriate tag and specify the parts of the
        arrow to be changed.

        The <position>s are specified by either x,y or x,y,z, and may
        be preceded by ffiirrsstt, sseeccoonndd, ggrraapphh, or ssccrreeeenn to select the
        coordinate system.  Unspecified coordinates default to 0.  The
        endpoints can be specified in one of four coordinate sys-
        tems---ffiirrsstt or sseeccoonndd axes, ggrraapphh or ssccrreeeenn.  See ccoooorrddiinnaatteess
        for details.  A coordinate system specifier does not carry over
        from the "from" position to the "to" position.  Arrows outside
        the screen boundaries are permitted but may cause device
        errors.  If the endpoint is specified by "rto" instead of "to"
        it is drawn relatively to the start point.

        Specifying nnoohheeaadd produces an arrow drawn without a head---a
        line segment.  This gives you yet another way to draw a line
        segment on the plot.  By default, arrows have heads. Specifying
        hheeaaddss draws arrow heads on both ends of the line.

        Head size can be controlled by ssiizzee <<lleennggtthh>>,,<<aannggllee>>, where
        <length> defines length of each branch of the arrow head and
        <angle> the angle (in degrees) they make with the arrow.
        <Length> is in x-axis units; this can be changed by ffiirrsstt, sseecc--
        oonndd, ggrraapphh or ssccrreeeenn before the <length>; see ccoooorrddiinnaatteess for
        details.

        Specifying ffiilllleedd produces filled arrow heads (if heads are
        used).  Filling is supported on filled-polygon capable termi-
        nals, see help of ppmm33dd for their list, otherwise the arrow
        heads are closed but not filled.  Further, filling is obviously
        not supported on terminals drawing arrows by their own specific
        routines, like ffiigg, mmeettaaffoonntt, mmeettaappoosstt, llaatteexx or ttggiiff.











   GNUPLOT 4.0                                                       68


        The line style may be selected from a user-defined list of line
        styles (see sseett ssttyyllee lliinnee) or may be defined here by providing
        values for <line_type> (an index from the default list of
        styles) and/or <line_width> (which is a  multiplier for the
        default width).

        Note, however, that if a user-defined line style has been
        selected, its properties (type and width) cannot be altered
        merely by issuing another sseett aarrrrooww command with the appropri-
        ate index and lltt or llww.

        If ffrroonntt is given, the arrow is written on top of the graphed
        data. If bbaacckk is given (the default), the arrow is written
        underneath the graphed data.  Using ffrroonntt will prevent an arrow
        from being obscured by dense data.

        Examples:

        To set an arrow pointing from the origin to (1,2) with user-
        defined style 5, use:
              set arrow to 1,2 ls 5

        To set an arrow from bottom left of plotting area to (-5,5,3),
        and tag the arrow number 3, use:
              set arrow 3 from graph 0,0 to -5,5,3

        To change the preceding arrow to end at 1,1,1, without an arrow
        head and double its width, use:
              set arrow 3 to 1,1,1 nohead lw 2

        To draw a vertical line from the bottom to the top of the graph
        at x=3, use:
              set arrow from 3, graph 0 to 3, graph 1 nohead

        To draw a vertical arrow with T-shape ends, use:
              set arrow 3 from 0,-5 to 0,5 heads size screen 0.1,90

        To draw an arrow relatively to the start point, where the rela-
        tive distances are given in graph coordinates, use:
              set arrow from 0,-5 rto graph 0.1,0.1

        To delete arrow number 2, use:
              unset arrow 2

        To delete all arrows, use:
              unset arrow

        To show all arrows (in tag order), use:
              show arrow
        See also arrows demos.













   GNUPLOT 4.0                                                       69


        3388..33..  AAuuttoossccaallee


        Autoscaling may be set individually on the x, y or z axis or
        globally on all axes. The default is to autoscale all axes.

        Syntax:
              set autoscale {<axes>{|min|max|fixmin|fixmax|fix} | fix |
        keepfix}
              unset autoscale {<axes>}
              show autoscale

        where <axes> is either xx, yy, zz, ccbb, xx22, yy22 or xxyy.  A keyword
        with mmiinn or mmaaxx appended (this cannot be done with xxyy) tells
        ggnnuupplloott to autoscale just the minimum or maximum of that axis.
        If no keyword is given, all axes are autoscaled.

        A keyword with ffiixxmmiinn, ffiixxmmaaxx or ffiixx appended tells gnuplot to
        disable extension of the axis range to the next tic mark posi-
        tion, for autoscaled axes using equidistant tics; sseett aauuttoossccaallee
        ffiixx sets this for all axes.  Command sseett aauuttoossccaallee kkeeeeppffiixx
        autoscales all axes while keeping the fix settings.

        When autoscaling, the axis range is automatically computed and
        the dependent axis (y for a pplloott and z for sspplloott) is scaled to
        include the range of the function or data being plotted.

        If autoscaling of the dependent axis (y or z) is not set, the
        current y or z range is used.

        Autoscaling the independent variables (x for pplloott and x,y for
        sspplloott) is a request to set the domain to match any data file
        being plotted.  If there are no data files, autoscaling an
        independent variable has no effect.  In other words, in the
        absence of a data file, functions alone do not affect the x
        range (or the y range if plotting z = f(x,y)).

        Please see sseett xxrraannggee for additional information about ranges.

        The behavior of autoscaling remains consistent in parametric
        mode, (see sseett ppaarraammeettrriicc).  However, there are more dependent
        variables and hence more control over x, y, and z axis scales.
        In parametric mode, the independent or dummy variable is t for
        ppllootts and u,v for ssppllootts.  aauuttoossccaallee in parametric mode, then,
        controls all ranges (t, u, v, x, y, and z) and allows x, y, and
        z to be fully autoscaled.

        Autoscaling works the same way for polar mode as it does for
        parametric mode for pplloott, with the extension that in polar mode
        sseett dduummmmyy can be used to change the independent variable from t
        (see sseett dduummmmyy).

        When tics are displayed on second axes but no plot has been










   GNUPLOT 4.0                                                       70


        specified for those axes, x2range and y2range are inherited
        from xrange and yrange.  This is done _before_ xrange and
        yrange are autoextended to a whole number of tics, which can
        cause unexpected results.  You can use the ffiixxmmiinn or ffiixxmmaaxx
        options to avoid this.

        Examples:

        This sets autoscaling of the y axis (other axes are not
        affected):
              set autoscale y

        This sets autoscaling only for the minimum of the y axis (the
        maximum of the y axis and the other axes are not affected):
              set autoscale ymin

        This disables extension of the x2 axis tics to the next tic
        mark, thus keeping the exact range as found in the plotted data
        and functions:
              set autoscale x2fixmin
              set autoscale x2fixmax

        This sets autoscaling of the x and y axes:
              set autoscale xy

        This sets autoscaling of the x, y, z, x2 and y2 axes:
              set autoscale

        This disables autoscaling of the x, y, z, x2 and y2 axes:
              unset autoscale

        This disables autoscaling of the z axis only:
              unset autoscale z




             3388..33..11..  PPaarraammeettrriicc mmooddee


             When in parametric mode (sseett ppaarraammeettrriicc), the xrange is as
             fully scalable as the y range.  In other words, in para-
             metric mode the x axis can be automatically scaled to fit
             the range of the parametric function that is being plot-
             ted.  Of course, the y axis can also be automatically
             scaled just as in the non-parametric case.  If autoscaling
             on the x axis is not set, the current x range is used.

             Data files are plotted the same in parametric and non-
             parametric mode.  However, there is a difference in mixed
             function and data plots: in non-parametric mode with
             autoscaled x, the x range of the datafile controls the x
             range of the functions; in parametric mode it has no










   GNUPLOT 4.0                                                       71


             influence.

             For completeness a last command sseett aauuttoossccaallee tt is
             accepted.  However, the effect of this "scaling" is very
             minor.  When ggnnuupplloott determines that the t range would be
             empty, it makes a small adjustment if autoscaling is true.
             Otherwise, ggnnuupplloott gives an error.  Such behavior may, in
             fact, not be very useful and the command sseett aauuttoossccaallee tt
             is certainly questionable.

             sspplloott extends the above ideas as you would expect.  If
             autoscaling is set, then x, y, and z ranges are computed
             and each axis scaled to fit the resulting data.



             3388..33..22..  PPoollaarr mmooddee


             When in polar mode (sseett ppoollaarr), the xrange and the yrange
             are both found from the polar coordinates, and thus they
             can both be automatically scaled.  In other words, in
             polar mode both the x and y axes can be automatically
             scaled to fit the ranges of the polar function that is
             being plotted.

             When plotting functions in polar mode, the rrange may be
             autoscaled.  When plotting data files in polar mode, the
             trange may also be autoscaled.  Note that if the trange is
             contained within one quadrant, autoscaling will produce a
             polar plot of only that single quadrant.

             Explicitly setting one or two ranges but not others may
             lead to unexpected results.  See also polar demos.



        3388..44..  BBaarrss


        The sseett bbaarrss command controls the tics at the ends of error
        bars, and also the width of the boxes in plot styles candle-
        sticks and financebars.

        Syntax:
              set bars {small | large | <size>}
              unset bars
              show bars

        ssmmaallll is a synonym for 0.0, and llaarrggee for 1.0.  The default is
        1.0 if no size is given.












   GNUPLOT 4.0                                                       72


        3388..55..  BBmmaarrggiinn


        The command sseett bbmmaarrggiinn sets the size of the bottom margin.
        Please see sseett mmaarrggiinn for details.



        3388..66..  BBoorrddeerr


        The sseett bboorrddeerr and uunnsseett bboorrddeerr commands control the display of
        the graph borders for the pplloott and sspplloott commands.  Note that
        the borders do not necessarily coincide with the axes; with
        pplloott they often do, but with sspplloott they usually do not.

        Syntax:
              set border {<integer> { {linestyle | ls <line_style>}
                                      | {linetype | lt <line_type> }
                                        {linewidth | lw <line_width>} }
        }
              unset border
              show border

        With a sspplloott displayed in an arbitrary orientation, like sseett
        vviieeww 5566,,110033, the four corners of the x-y plane can be referred
        to as "front", "back", "left" and "right".  A similar set of
        four corners exist for the top surface, of course.  Thus the
        border connecting, say, the back and right corners of the x-y
        plane is the "bottom right back" border, and the border con-
        necting the top and bottom front corners is the "front verti-
        cal".  (This nomenclature is defined solely to allow the reader
        to figure out the table that follows.)

        The borders are encoded in a 12-bit integer: the bottom four
        bits control the border for pplloott and the sides of the base for
        sspplloott; the next four bits control the verticals in sspplloott; the
        top four bits control the edges on top of the sspplloott.  In
        detail, <<iinntteeggeerr>> should be the sum of the appropriate entries
        from the following table:























   GNUPLOT 4.0                                                       73


                 +--------------------------------------+
                 |Bit      plot            splot        |
                 +--------------------------------------+
                 | 1      bottom     bottom left front  |
                 | 2       left       bottom left back  |
                 | 4        top      bottom right front |
                 | 8       right     bottom right back  |
                 | 16    no effect     left vertical    |
                 | 32    no effect     back vertical    |
                 | 64    no effect     right vertical   |
                 |128    no effect     front vertical   |
                 |256    no effect     top left back    |
                 |512    no effect     top right back   |
                 |1024   no effect     top left front   |
                 |2048   no effect    top right front   |
                 +--------------------------------------+



   Various bits or combinations of bits may be added together in the
   command.

   The default is 31, which is all four sides for pplloott, and base and z
   axis for sspplloott.

   Using the optional <line_style>, <line_type> and <line_width> speci-
   fiers, the way the border lines are drawn can be influenced (limited
   by what the current terminal driver supports).

   For pplloott, tics may be drawn on edges other than bottom and left by
   enabling the second axes -- see sseett xxttiiccss for details.

   If a sspplloott draws only on the base, as is the case with "uunnsseett ssuurr--
   ffaaccee;; sseett ccoonnttoouurr bbaassee", then the verticals and the top are not
   drawn even if they are specified.

   The sseett ggrriidd options 'back', 'front' and 'layerdefault' also control
   the order in which the border lines are drawn with respect to the
   output of the plotted data.

   Examples:

   Draw default borders:
         set border

   Draw only the left and bottom (pplloott) or both front and back bottom
   left (sspplloott) borders:
         set border 3

   Draw a complete box around a sspplloott:
         set border 4095

   Draw a topless box around a sspplloott, omitting the front vertical:










   GNUPLOT 4.0                                                       74


         set border 127+256+512 # or set border 1023-128

   Draw only the top and right borders for a pplloott and label them as
   axes:
         unset xtics; unset ytics; set x2tics; set y2tics; set border
   12

   See also borders demo.



        3388..77..  BBooxxwwiiddtthh


        The sseett bbooxxwwiiddtthh command is used to set the default width of
        boxes in the bbooxxeess, bbooxxeerrrroorrbbaarrss and ccaannddlleessttiicckkss styles.

        Syntax:
              set boxwidth {<width>} {absolute|relative}
              show boxwidth

        If a data file is plotted without the width being specified in
        the third, fourth, or fifth column (or uussiinngg entry), or if a
        function is plotted, the width of each box is set by the sseett
        bbooxxwwiiddtthh command.  (If a width is given both in the file and by
        the sseett bbooxxwwiiddtthh command, the one in the file is used.)  If the
        width is not specified in one of these ways, the width of each
        box will be calculated automatically so that it touches the
        adjacent boxes.  rreellaattiivvee indicates, that the specified
        boxwidth is a scaling factor for the automatically calculated
        boxwidth, otherwise the boxwidth is taken as an aabbssoolluuttee value
        (which is the default). In a four-column data set, the fourth
        column will be interpreted as the box width unless the width is
        set to -2.0, in which case the width will be calculated auto-
        matically.  See sseett ssttyyllee bbooxxeerrrroorrbbaarrss for more details.

        To set the box width to automatic use the command
              set boxwidth

        or, for four-column data,
              set boxwidth -2

        The same effect can be achieved with the uussiinngg keyword in pplloott:
              plot 'file' using 1:2:3:4:(-2)

        To set the box width to half of the automatic size use
              set boxwidth 0.5 relative

        To set the box width to an absolute value of 2 use
              set boxwidth 2 absolute

        or, if you didn't specify a relative boxwidth before,
              set boxwidth 2










   GNUPLOT 4.0                                                       75


        3388..88..  CCllaabbeell


        ggnnuupplloott will vary the linetype used for each contour level when
        clabel is set.  When this option on (the default), a legend
        labels each linestyle with the z level it represents.  It is
        not possible at present to separate the contour labels from the
        surface key.

        Syntax:
              set clabel {'<format>'}
              unset clabel
              show clabel

        The default for the format string is %8.3g, which gives three
        decimal places.  This may produce poor label alignment if the
        key is altered from its default configuration.

        The first contour linetype, or only contour linetype when cla-
        bel is off, is the surface linetype +1; contour points are the
        same style as surface points.

        See also sseett ccoonnttoouurr.



        3388..99..  CClliipp


        ggnnuupplloott can clip data points and lines that are near the bound-
        aries of a graph.

        Syntax:
              set clip <clip-type>
              unset clip <clip-type>
              show clip

        Three clip types for points and lines are supported by ggnnuupplloott:
        ppooiinnttss, oonnee, and ttwwoo. One, two, or all three clip types may be
        active for a single graph.  Note that clipping of color filled
        quadrangles drawn by ppmm33dd maps and surfaces is not controlled
        by this command, but by sseett ppmm33dd cclliipp11iinn and sseett ppmm33dd cclliipp44iinn.

        The ppooiinnttss clip type forces ggnnuupplloott to clip (actually, not plot
        at all) data points that fall within but too close to the
        boundaries.  This is done so that large symbols used for points
        will not extend outside the boundary lines.  Without clipping
        points near the boundaries, the plot may look bad.  Adjusting
        the x and y ranges may give similar results.

        Setting the oonnee clip type causes ggnnuupplloott to draw a line segment
        which has only one of its two endpoints within the graph.  Only
        the in-range portion of the line is drawn.  The alternative is










   GNUPLOT 4.0                                                       76


        to not draw any portion of the line segment.

        Some lines may have both endpoints out of range, but pass
        through the graph.  Setting the ttwwoo clip-type allows the visi-
        ble portion of these lines to be drawn.

        In no case is a line drawn outside the graph.

        The defaults are nnoocclliipp ppooiinnttss, cclliipp oonnee, and nnoocclliipp ttwwoo.

        To check the state of all forms of clipping, use
              show clip

        For backward compatibility with older versions, the following
        forms are also permitted:
              set clip
              unset clip

        sseett cclliipp is synonymous with sseett cclliipp ppooiinnttss; uunnsseett cclliipp turns
        off all three types of clipping.



        3388..1100..  CCnnttrrppaarraamm


        sseett ccnnttrrppaarraamm controls the generation of contours and their
        smoothness for a contour plot. sshhooww ccoonnttoouurr displays current
        settings of ccnnttrrppaarraamm as well as ccoonnttoouurr.

        Syntax:
              set cntrparam { { linear
                              | cubicspline
                              | bspline
                              | points <n>
                              | order <n>
                              | levels { auto {<n>} | <n>
                                         | discrete <z1>
        {,<z2>{,<z3>...}}
                                         | incremental <start>, <incr>
        {,<end>}
                                       }
                              }
                            }
              show contour

        This command has two functions.  First, it sets the values of z
        for which contour points are to be determined (by linear inter-
        polation between data points or function isosamples.)  Second,
        it controls the way contours are drawn between the points
        determined to be of equal z.  <n> should be an integral con-
        stant expression and <z1>, <z2> ... any constant expressions.
        The parameters are:










   GNUPLOT 4.0                                                       77


        lliinneeaarr, ccuubbiiccsspplliinnee, bbsspplliinnee---Controls type of approximation
        or interpolation.  If lliinneeaarr, then straight line segments con-
        nect points of equal z magnitude.  If ccuubbiiccsspplliinnee, then piece-
        wise-linear contours are interpolated between the same equal z
        points to form somewhat smoother contours, but which may undu-
        late.  If bbsspplliinnee, a guaranteed-smoother curve is drawn, which
        only approximates the position of the points of equal-z.

        ppooiinnttss---Eventually all drawings are done with piecewise-linear
        strokes.  This number controls the number of line segments used
        to approximate the bbsspplliinnee or ccuubbiiccsspplliinnee curve.  Number of
        cubicspline or bspline segments (strokes) = ppooiinnttss * number of
        linear segments.

        oorrddeerr---Order of the bspline approximation to be used.  The
        bigger this order is, the smoother the resulting contour.  (Of
        course, higher order bspline curves will move further away from
        the original piecewise linear data.)  This option is relevant
        for bbsspplliinnee mode only.  Allowed values are integers in the
        range from 2 (linear) to 10.

        lleevveellss--- Selection of contour levels,  controlled by aauuttoo
        (default), ddiissccrreettee, iinnccrreemmeennttaall, and <n>, number of contour
        levels, limited to
         MAX_DISCRETE_LEVELS as defined in plot.h (30 is standard.)

        For aauuttoo, <n> specifies a nominal number of levels; the actual
        number will be adjusted to give simple labels. If the surface
        is bounded by zmin and zmax, contours will be generated at
        integer multiples of dz between zmin and zmax, where dz is 1,
        2, or 5 times some power of ten (like the step between two tic
        marks).

        For lleevveellss ddiissccrreettee, contours will be generated at z = <z1>,
        <z2> ... as specified; the number of discrete levels sets the
        number of contour levels.  In ddiissccrreettee mode, any sseett ccnnttrrppaarraamm
        lleevveellss <<nn>> are ignored.

        For iinnccrreemmeennttaall, contours are generated at values of z begin-
        ning at <start> and increasing by <increment>, until the number
        of contours is reached. <end> is used to determine the number
        of contour levels, which will be changed by any subsequent sseett
        ccnnttrrppaarraamm lleevveellss <<nn>>.

        If the command sseett ccnnttrrppaarraamm is given without any arguments
        specified,  the defaults are used: linear, 5 points, order 4, 5
        auto levels.

        Examples:
              set cntrparam bspline
              set cntrparam points 7
              set cntrparam order 10











   GNUPLOT 4.0                                                       78


        To select levels automatically, 5 if the level increment crite-
        ria are met:
              set cntrparam levels auto 5

        To specify discrete levels at .1, .37, and .9:
              set cntrparam levels discrete .1,1/exp(1),.9

        To specify levels from 0 to 4 with increment 1:
              set cntrparam levels incremental  0,1,4

        To set the number of levels to 10 (changing an incremental end
        or possibly the number of auto levels):
              set cntrparam levels 10

        To set the start and increment while retaining the number of
        levels:
              set cntrparam levels incremental 100,50

        See also sseett ccoonnttoouurr for control of where the contours are
        drawn, and sseett ccllaabbeell for control of the format of the contour
        labels and linetypes.

        See also contours demo (contours.dem) and contours with user
        defined levels demo (discrete.dem).



        3388..1111..  CCoolloorr bbooxx



        The color scheme, i.e. the gradient of the smooth color with
        min_z and max_z values of ppmm33dd's ppaalleettttee, is drawn in a color
        box unless uunnsseett ccoolloorrbbooxx.

              set colorbox
              set colorbox {
                         { vertical | horizontal }
                         { default | user }
                         { origin x, y }
                         { size x, y }
                         { noborder | bdefault | border [line style] }
                       }
              show colorbox
              unset colorbox

        Colorbox position can be ddeeffaauulltt or uusseerr.  If the latter is
        specified the values as given with the oorriiggiinn and ssiizzee subcom-
        mands are used.

        vveerrttiiccaall and hhoorriizzoonnttaall switches the orientation of the color
        gradient.











   GNUPLOT 4.0                                                       79


        oorriiggiinn xx,, yy and ssiizzee xx,, yy are used only in combination with the
        uusseerr option. The x and y values must be given in screen coordi-
        nates (as everything else did not seem to make sense) that is
        between [0 - 1]. Try for example:
            set colorbox horiz user origin .1,.02 size .8,.04
        which will draw a horizontal gradient somewhere at the bottom
        of the graph.

        bboorrddeerr turns the border on (this is the default). nnoobboorrddeerr
        turns the border off. If an positive integer argument is given
        after bboorrddeerr, it is used as a line style tag which is used for
        drawing the border, e.g.:
            set style line 2604 linetype -1 linewidth .4
            set colorbox border 2604
        will use line style 22660044, a thin line with the default border
        color (-1) for drawing the border. bbddeeffaauulltt (which is the
        default) will use the default border line style for drawing the
        border of the color box.

        The axis of the color box is called ccbb and it is controlled by
        means of the usual axes commands, i.e. sseett//uunnsseett//sshhooww with
        ccbbrraannggee, [[mm]]ccbbttiiccss, ffoorrmmaatt ccbb, ggrriidd [[mm]]ccbb, ccbbllaabbeell, and perhaps
        even ccbbddaattaa, [[nnoo]]ccbbddttiiccss, [[nnoo]]ccbbmmttiiccss.

        sseett ccoolloorrbbooxx without any parameter switches the position to
        default.  uunnsseett ccoolloorrbbooxx resets the default parameters for the
        colorbox and switches the colorbox off.

        See also help for sseett ppmm33dd, sseett ppaalleettttee, xx1111 ppmm33dd, and sseett
        ssttyyllee lliinnee.




        3388..1122..  CCoonnttoouurr


        sseett ccoonnttoouurr enables contour drawing for surfaces. This option
        is available for sspplloott only.

        Syntax:
              set contour {base | surface | both}
              unset contour
              show contour

        The three options specify where to draw the contours: bbaassee
        draws the contours on the grid base where the x/ytics are
        placed, ssuurrffaaccee draws the contours on the surfaces themselves,
        and bbootthh draws the contours on both the base and the surface.
        If no option is provided, the default is bbaassee.

        See also sseett ccnnttrrppaarraamm for the parameters that affect the draw-
        ing of contours, and sseett ccllaabbeell for control of labelling of the










   GNUPLOT 4.0                                                       80


        contours.

        The surface can be switched off (see sseett ssuurrffaaccee), giving a
        contour-only graph.  Though it is possible to use sseett ssiizzee to
        enlarge the plot to fill the screen, more control over the out-
        put format can be obtained by writing the contour information
        to a file, and rereading it as a 2-d datafile plot:

              unset surface
              set contour
              set cntrparam ...
              set term table
              set out 'filename'
              splot ...
              set out
              # contour info now in filename
              set term <whatever>
              plot 'filename'

        In order to draw contours, the data should be organized as
        "grid data".  In such a file all the points for a single y-iso-
        line are listed, then all the points for the next y-isoline,
        and so on.  A single blank line (a line containing no charac-
        ters other than blank spaces and a carriage return and/or a
        line feed) separates one y-isoline from the next.  See also
        sspplloott ddaattaaffiillee.


        If contours are desired from non-grid data, sseett ddggrriidd33dd can be
        used to create an appropriate grid.  See sseett ddggrriidd33dd for more
        information.  See also contours demo (contours.dem) and con-
        tours with user defined levels demo (discrete.dem).



        3388..1133..  DDaattaa ssttyyllee


        This form of the command is deprecated. Please see sseett ssttyyllee
        ddaattaa.



        3388..1144..  DDaattaaffiillee


        The sseett ddaattaaffiillee command options control interpretation of
        fields read from input data files by the pplloott, sspplloott, and ffiitt
        commands.  Three such options are currently implemented.














   GNUPLOT 4.0                                                       81


             3388..1144..11..  SSeett ddaattaaffiillee mmiissssiinngg


             The sseett ddaattaaffiillee mmiissssiinngg command allows you to tell ggnnuu--
             pplloott what character string is used in a data file to
             denote missing data.  Exactly how this missing value will
             be treated depends on the uussiinngg specifier of the pplloott or
             sspplloott command.

             Syntax:
                   set datafile missing {"<string>"}
                   show datafile missing
                   unset datafile

             Example:
                   # Ignore entries containing IEEE NaN ("Not a Num-
             ber") code
                   set datafile missing "NaN"

             Example:
                   set datafile missing "?"
                   set style data lines
                   plot '-'
                      1 10
                      2 20
                      3 ?
                      4 40
                      5 50
                      e
                   plot '-' using 1:2
                      1 10
                      2 20
                      3 ?
                      4 40
                      5 50
                      e
                   plot '-' using 1:($2)
                      1 10
                      2 20
                      3 ?
                      4 40
                      5 50
                      e

             The first pplloott will recognize only the first datum in the
             "3 ?" line.  It will use the single-datum-on-a-line con-
             vention that the line number is "x" and the datum is "y",
             so the point will be plotted (in this case erroneously) at
             (2,3).

             The second pplloott will correctly ignore the middle line.
             The plotted line will connect the points at (2,20) and
             (4,40).










   GNUPLOT 4.0                                                       82


             The third pplloott will also correctly ignore the middle line,
             but the plotted line will not connect the points at (2,20)
             and (4,40).

             There is no default character for mmiissssiinngg, but in many
             cases any non-parsible string of characters found where a
             numerical value is expected will be treated as missing
             data.




             3388..1144..22..  SSeett ddaattaaffiillee sseeppaarraattoorr


             The command sseett ddaattaaffiillee sseeppaarraattoorr ""<<cchhaarr>>"" tells ggnnuupplloott
             that data fields in subsequent input files are separated
             by <char> rather than by whitespace.  The most common use
             is to read in csv (comma-separated value) files written by
             spreadsheet or database programs. By default data fields
             are separated by whitespace.

             Syntax:
                   set datafile separator {"<char>" | whitespace}

             Examples:
                   # Input file contains tab-separated fields
                   set datafile separator "\t"

                   # Input file contains comma-separated values fields
                   set datafile separator ","



             3388..1144..33..  SSeett ddaattaaffiillee ccoommmmeennttsscchhaarrss


             The sseett ddaattaaffiillee ccoommmmeennttsscchhaarrss command allows you to tell
             ggnnuupplloott what characters are used in a data file to denote
             comments.  Gnuplot will ignore rest of the line behind the
             specified characters if either of them is the first non-
             blank character on the line.

             Syntax:
                   set datafile commentschars {"<string>"}
                   show datafile commentschars
                   unset commentschars

             Default value of the string is "#!" on VMS and "#" other-
             wise.

             Then, the following line in a data file is completely
             ignored










   GNUPLOT 4.0                                                       83


                 # 1 2 3 4
             but the following
                 1 # 3 4
             produces rather unexpected plot unless
                 set datafile missing '#'
             is specified as well.

             Example:
                   set datafile commentschars "#!%"



        3388..1155..  DDeecciimmaallssiiggnn


        The sseett ddeecciimmaallssiiggnn command selects a decimal sign for numbers
        printed into tic labels or sseett llaabbeell strings.

        Syntax:
              set decimalsign {<value>}
              unset decimalsign
              show decimalsign

        The argument <value> is the string to be used in place of the
        usual decimal point. Typical choices include the period, '.',
        and the comma, ',', but others may be useful, too.  If you omit
        the <value> argument, the decimal separator is not modified
        from the usual default, which is a period.  Unsetting decimal-
        sign has the same effect as omitting <value>.

        Example:

        Correct typesetting in most European countries requires:
              set decimalsign ','



        3388..1166..  DDggrriidd33dd


        The sseett ddggrriidd33dd command enables, and can set parameters for,
        non-grid to grid data mapping.

        Syntax:
              set dgrid3d {<row_size>} {,{<col_size>} {,<norm>}}
              unset dgrid3d
              show dgrid3d

        By default ddggrriidd33dd is disabled.  When enabled, 3-d data read
        from a file are always treated as a scattered data set.  A grid
        with dimensions derived from a bounding box of the scattered
        data and size as specified by the row/col_size parameters is
        created for plotting and contouring.  The grid is equally










   GNUPLOT 4.0                                                       84


        spaced in x (rows) and in y (columns); the z values are com-
        puted as weighted averages of the scattered points' z values.

        The third parameter, norm, controls the weighting:  Each data
        point is weighted inversely by its distance from the grid point
        raised to the norm power.  (Actually, the weights are given by
        the inverse of dx^norm + dy^norm, where dx and dy are the com-
        ponents of the separation of the grid point from each data
        point.  For some norms that are powers of two, specifically 4,
        8, and 16, the computation is optimized by using the Euclidean
        distance in the weight calculation, (dx^2+dy^2)^norm/2.  How-
        ever, any non-negative integer can be used.)

        The closer the data point is to a grid point, the more effect
        it has on that grid point and the larger the value of norm the
        less effect more distant data points have on that grid point.

        The ddggrriidd33dd option is a simple low pass filter that converts
        scattered data to a grid data set.  More sophisticated
        approaches to this problem exist and should be used to prepro-
        cess the data outside ggnnuupplloott if this simple solution is found
        inadequate.

        (The z values are found by weighting all data points, not by
        interpolating between nearby data points;  also edge effects
        may produce unexpected and/or undesired results.  In some
        cases, small norm values produce a grid point reflecting the
        average of distant data points rather than a local average,
        while large values of norm may produce "steps" with several
        grid points having the same value as the closest data point,
        rather than making a smooth transition between adjacent data
        points.  Some areas of a grid may be filled by extrapolation,
        to an arbitrary boundary condition.  The variables are not nor-
        malized; consequently the units used for x and y will affect
        the relative weights of points in the x and y directions.)

        Examples:
              set dgrid3d 10,10,1     # defaults
              set dgrid3d ,,4

        The first specifies that a grid of size 10 by 10 is to be con-
        structed using a norm value of 1 in the weight computation.
        The second only modifies the norm, changing it to 4.  See also
        scatter.dem: dgrid3d demo.




        3388..1177..  DDuummmmyy


        The sseett dduummmmyy command changes the default dummy variable names.











   GNUPLOT 4.0                                                       85


        Syntax:
              set dummy {<dummy-var>} {,<dummy-var>}
              show dummy

        By default, ggnnuupplloott assumes that the independent, or "dummy",
        variable for the pplloott command is "t" if in parametric or polar
        mode, or "x" otherwise.  Similarly the independent variables
        for the sspplloott command are "u" and "v" in parametric mode (sspplloott
        cannot be used in polar mode), or "x" and "y" otherwise.

        It may be more convenient to call a dummy variable by a more
        physically meaningful or conventional name.  For example, when
        plotting time functions:

              set dummy t
              plot sin(t), cos(t)

        At least one dummy variable must be set on the command; sseett
        dduummmmyy by itself will generate an error message.

        Examples:
              set dummy u,v
              set dummy ,s

        The second example sets the second variable to s.



        3388..1188..  EEnnccooddiinngg


        The sseett eennccooddiinngg command selects a character encoding.  Syntax:
              set encoding {<value>}
              show encoding

        Valid values are
           default     - tells a terminal to use its default encoding
           iso_8859_1  - the most common Western European font used by
        many
                         Unix workstations and by MS-Windows. This
        encoding is
                         known in the PostScript world as 'ISO-Latin1'.
           iso_8859_2  - used in Central and Eastern Europe
           iso_8859_15 - a variant of iso_8859_1 that includes the Euro
        symbol
           cp850       - codepage for OS/2
           cp852       - codepage for OS/2
           cp437       - codepage for MS-DOS
           koi8r       - popular Unix cyrillic encoding

        Generally you must set the encoding before setting the terminal
        type.  Note that encoding is not supported by all terminal
        drivers and that the device must be able to produce the desired










   GNUPLOT 4.0                                                       86


        non-standard characters.  The PostScript and X11 terminals sup-
        port all encodings. OS/2 Presentation Manager switches automat-
        ically to codepage 912 for iissoo__88885599__22.



        3388..1199..  FFiitt


        The ffiitt setting defines where the ffiitt command writes its out-
        put.  If this option was built into your version of gnuplot, it
        also controls whether parameter errors from the fit will be
        written into variables.

        Syntax:
              set fit {logfile {"<filename>"}} {{no}errorvariables}
              unset fit
              show fit

        The <filename> argument must be enclosed in single or double
        quotes.

        If no filename is given or uunnsseett ffiitt is used the log file is
        reset to its default value "fit.log" or the value of the envi-
        ronmental variable FFIITT__LLOOGG.

        Users of DOS-like platforms should note that the \ character
        has special significance in double-quoted strings, so single-
        quotes should be used for filenames in different directories,
        or you have to write \\ for each \.  Or you can just use for-
        ward slashes, even though this is DOS.

        If the given logfile name ends with a / or \, it is interpreted
        to be a directory name, and the actual filename will be
        "fit.log" in that directory.

        If the eerrrroorrvvaarriiaabblleess option is turned on, the error of each
        fitted parameter computed by ffiitt will be copied to a user-
        defined variable whose name is formed by appending "_err" to
        the name of the parameter itself.  This is useful mainly to put
        the parameter and its error onto a plot of the data and the
        fitted function, for reference, as in:

               set fit errorvariables
               fit f(x) 'datafile' using 1:2 via a, b
               print "error of a is:", a_err
               set label 'a=%6.2f', a, '+/- %6.2f', a_err
               plot 'datafile' using 1:2, f(x)















   GNUPLOT 4.0                                                       87


        3388..2200..  FFoonnttppaatthh


        The ffoonnttppaatthh setting defines additional locations for font
        files searched when including font files. Currently only the
        postscript terminal supports ffoonnttppaatthh. If a file cannot be
        found in the current directory, the directories in ffoonnttppaatthh are
        tried. Further documentation concerning the supported file for-
        mats is included in the tteerrmmiinnaall ppoossttssccrriipptt section of the doc-
        umentation.

        Syntax:
              set fontpath {"pathlist1" {"pathlist2"...}}
              show fontpath

        Path names may be entered as single directory names, or as a
        list of path names separated by a platform-specific path sepa-
        rator, eg. colon (':') on Unix, semicolon (';') on DOS/Win-
        dows/OS/2/Amiga platforms.  The sshhooww ffoonnttppaatthh, ssaavvee and ssaavvee
        sseett commands replace the platform-specific separator with a
        space character (' ') for maximum portability. If a directory
        name ends with an exclamation mark ('!') also the subdirecto-
        ries of this directory are searched for font files.

        If the environmental variable GNUPLOT_FONTPATH is set, its con-
        tents are appended to ffoonnttppaatthh.  If it is not set, a system
        dependent default value is used. It is set by testing several
        directories for existence when using the fontpath the first
        time. Thus, the first call of sseett ffoonnttppaatthh, sshhooww ffoonnttppaatthh, ssaavvee
        ffoonnttppaatthh, pplloott, or sspplloott with embedded font files takes a lit-
        tle more time. If you want to save this time you may set the
        environmental variable GNUPLOT_FONTPATH since probing is
        switched off, then. You can find out which is the default font-
        path by using sshhooww ffoonnttppaatthh.

        However, sshhooww ffoonnttppaatthh prints the contents of user defined
        fontpath and system fontpath separately.  Also, the ssaavvee and
        ssaavvee sseett commands save only the user specified parts of ffoonntt--
        ppaatthh, for portability reasons.

        Many other terminal drivers access TrueType fonts via the gd
        library.  For these drivers the font search path is controlled
        by the environmental variable GDFONTPATH.



        3388..2211..  FFoorrmmaatt


        The format of the tic-mark labels can be set with the sseett ffoorr--
        mmaatt command.

        Syntax:










   GNUPLOT 4.0                                                       88


              set format {<axes>} {"<format-string>"}
              set format {<axes>} {'<format-string>'}
              show format

        where <axes> is either xx, yy, zz, ccbb, xxyy, xx22, yy22 or nothing
        (which is the same as xxyy).  The length of the string represent-
        ing a tic mark (after formatting with 'printf') is restricted
        to 100 characters.  If the format string is omitted, the format
        will be returned to the default "%g".  For LaTeX users, the
        format "$%g$" is often desirable.  If the empty string "" is
        used, no label will be plotted with each tic, though the tic
        mark will still be plotted.  To eliminate all tic marks, use
        uunnsseett xxttiiccss or uunnsseett yyttiiccss.

        Newline (\n) is accepted in the format string.  Use double-
        quotes rather than single-quotes to enable such interpretation.
        See also ssyynnttaaxx.

        The default format for both axes is "%g", but other formats
        such as "%.2f" or "%3.0em" are often desirable.  Anything
        accepted by 'printf' when given a double precision number, and
        accepted by the terminal, will work.  Some other options have
        been added.  If the format string looks like a floating point
        format, then ggnnuupplloott tries to construct a reasonable format.

        Characters not preceded by "%" are printed verbatim.  Thus you
        can include spaces and labels in your format string, such as
        "%g m", which will put " m" after each number.  If you want "%"
        itself, double it: "%g %%".

        See also sseett xxttiiccss for more information about tic labels, and
        sseett ddeecciimmaallssiiggnn for how to use non-default decimal separators
        in numbers printed this way.  See also electron demo (elec-
        tron.dem).




             3388..2211..11..  FFoorrmmaatt ssppeecciiffiieerrss


             The acceptable formats (if not in time/date mode) are:





















   GNUPLOT 4.0                                                       89


   +------------------------------------------------------------------+
   | Format    Explanation                                            |
   +------------------------------------------------------------------+
   |   %f      floating point notation                                |
   |%e or %E   exponential notation; an "e" or "E" before the power   |
   |%g or %G   the shorter of %e (or %E) and %f                       |
   |%x or %X   hex                                                    |
   |%o or %O   octal                                                  |
   |   %t      mantissa to base 10                                    |
   |   %l      mantissa to base of current logscale                   |
   |   %s      mantissa to base of current logscale; scientific power |
   |   %T      power to base 10                                       |
   |   %L      power to base of current logscale                      |
   |   %S      scientific power                                       |
   |   %c      character replacement for scientific power             |
   |   %P      multiple of pi                                         |
   +------------------------------------------------------------------+
   +------------------------------------------------------------------+



   A 'scientific' power is one such that the exponent is a multiple of
   three.  Character replacement of scientific powers (""%%cc"") has been
   implemented for powers in the range -18 to +18.  For numbers outside
   of this range the format reverts to exponential.

   Other acceptable modifiers (which come after the "%" but before the
   format specifier) are "-", which left-justifies the number; "+",
   which forces all numbers to be explicitly signed; "#", which places
   a decimal point after floats that have only zeroes following the
   decimal point; a positive integer, which defines the field width;
   "0" (the digit, not the letter) immediately preceding the field
   width, which indicates that leading zeroes are to be used instead of
   leading blanks; and a decimal point followed by a non-negative inte-
   ger, which defines the precision (the minimum number of digits of an
   integer, or the number of digits following the decimal point of a
   float).

   Some releases of 'printf' may not support all of these modifiers but
   may also support others; in case of doubt, check the appropriate
   documentation and then experiment.

   Examples:
         set format y "%t"; set ytics (5,10)          # "5.0" and "1.0"
         set format y "%s"; set ytics (500,1000)      # "500" and "1.0"
         set format y "+-12.3f"; set ytics(12345)     # "+12345.000  "
         set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
         set format y "%s*10^{%S}"; set ytic(12345)   # "12.345*10^{3}"
         set format y "%s %cg"; set ytic(12345)       # "12.345 kg"
         set format y "%.0P pi"; set ytic(6.283185)   # "2 pi"
         set format y "%.0f%%"; set ytic(50)          # "50%"

         set log y 2; set format y '%l'; set ytics (1,2,3)










   GNUPLOT 4.0                                                       90


         #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)

   There are some problem cases that arise when numbers like 9.999 are
   printed with a format that requires both rounding and a power.

   If the data type for the axis is time/date, the format string must
   contain valid codes for the 'strftime' function (outside of ggnnuupplloott,
   type "man strftime").  See sseett ttiimmeeffmmtt for a list of the allowed
   input format codes.



             3388..2211..22..  TTiimmee//ddaattee ssppeecciiffiieerrss


             In time/date mode, the acceptable formats are:




          +----------------------------------------------------+
          | Format    Explanation                              |
          +----------------------------------------------------+
          |   %a      abbreviated name of day of the week      |
          |   %A      full name of day of the week             |
          |%b or %h   abbreviated name of the month            |
          |   %B      full name of the month                   |
          |   %d      day of the month, 1--31                  |
          |   %D      shorthand for "%m/%d/%y"                 |
          |%H or %k   hour, 0--24                              |
          |%I or %l   hour, 0--12                              |
          |   %j      day of the year, 1--366                  |
          |   %m      month, 1--12                             |
          |   %M      minute, 0--60                            |
          |   %p      "am" or "pm"                             |
          |   %r      shorthand for "%I:%M:%S %p"              |
          |   %R      shorthand for %H:%M"                     |
          |   %S      second, 0--60                            |
          |   %T      shorthand for "%H:%M:%S"                 |
          |   %U      week of the year (week starts on Sunday) |
          |   %w      day of the week, 0--6 (Sunday = 0)       |
          |   %W      week of the year (week starts on Monday) |
          |   %y      year, 0-99                               |
          |   %Y      year, 4-digit                            |
          +----------------------------------------------------+
          +----------------------------------------------------+



   Except for the non-numerical formats, these may be preceded by a "0"
   ("zero", not "oh") to pad the field length with leading zeroes, and
   a positive digit, to define the minimum field width (which will be
   overridden if the specified width is not large enough to contain the










   GNUPLOT 4.0                                                       91


   number).  There is a 24-character limit to the length of the printed
   text; longer strings will be truncated.

   Examples:

   Suppose the text is "76/12/25 23:11:11".  Then
         set format x                 # defaults to "12/25/76" \n
   "23:11"
         set format x "%A, %d %b %Y"  # "Saturday, 25 Dec 1976"
         set format x "%r %D"         # "11:11:11 pm 12/25/76"

   Suppose the text is "98/07/06 05:04:03".  Then
         set format x "%1y/%2m/%3d %01H:%02M:%03S"  # "98/ 7/  6
   5:04:003"



        3388..2222..  FFuunnccttiioonn ssttyyllee


        This form of the command is deprecated. Please see sseett ssttyyllee
        ffuunnccttiioonn.



        3388..2233..  FFuunnccttiioonnss


        The sshhooww ffuunnccttiioonnss command lists all user-defined functions and
        their definitions.

        Syntax:
              show functions

        For information about the definition and usage of functions in
        ggnnuupplloott, please see eexxpprreessssiioonnss.  See also splines as user
        defined functions (spline.dem) and use of functions and complex
        variables for airfoils (airfoil.dem).



        3388..2244..  GGrriidd


        The sseett ggrriidd command allows grid lines to be drawn on the plot.

        Syntax:
              set grid {{no}{m}xtics} {{no}{m}ytics} {{no}{m}ztics}
                       {{no}{m}x2tics} {{no}{m}y2tics}
                       {{no}{m}cbtics}
                       {polar {<angle>}}
                       {layerdefault | front | back}
                       { {linestyle <major_linestyle>}










   GNUPLOT 4.0                                                       92


                         | {linetype | lt <major_linetype>}
                           {linewidth | lw <major_linewidth>}
                         { , {linestyle | ls <minor_linestyle>}
                             | {linetype | lt <minor_linetype>}
                               {linewidth | lw <minor_linewidth>} } }
              unset grid
              show grid

        The grid can be enabled and disabled for the major and/or minor
        tic marks on any axis, and the linetype and linewidth can be
        specified for major and minor grid lines, also via a predefined
        linestyle, as far as the active terminal driver supports this.

        Additionally, a polar grid can be selected for 2-d plots---cir-
        cles are drawn to intersect the selected tics, and radial lines
        are drawn at definable intervals.  (The interval is given in
        degrees or radians, depending on the sseett aanngglleess setting.)  Note
        that a polar grid is no longer automatically generated in polar
        mode.

        The pertinent tics must be enabled before sseett ggrriidd can draw
        them; ggnnuupplloott will quietly ignore instructions to draw grid
        lines at non-existent tics, but they will appear if the tics
        are subsequently enabled.

        If no linetype is specified for the minor gridlines, the same
        linetype as the major gridlines is used.  The default polar
        angle is 30 degrees.

        If ffrroonntt is given, the grid is drawn on top of the graphed
        data. If bbaacckk is given, the grid is drawn underneath the
        graphed data. Using ffrroonntt will prevent the grid from being
        obscured by dense data. The default setup, llaayyeerrddeeffaauulltt, is
        equivalent to bbaacckk for 2d plots.  In 3D plots the default is to
        split up the grid and the graph box into two layers: one
        behind, the other in front of the plotted data and functions.
        Since hhiiddddeenn33dd mode does its own sorting, it ignores all grid
        drawing order options and passes the grid lines through the
        hidden line removal machinery instead. These options actually
        affect not only the grid, but also the lines output by sseett bboorr--
        ddeerr and the various ticmarks (see sseett xxttiiccss).

        Z grid lines are drawn on the bottom of the plot.  This looks
        better if a partial box is drawn around the plot---see sseett bboorr--
        ddeerr.



        3388..2255..  HHiiddddeenn33dd


        The sseett hhiiddddeenn33dd command enables hidden line removal for sur-
        face plotting (see sspplloott).  Some optional features of the










   GNUPLOT 4.0                                                       93


        underlying algorithm can also be controlled using this command.

        Syntax:
              set hidden3d {defaults} |
                           { {{offset <offset>} | {nooffset}}
                             {trianglepattern <bitpattern>}
                             {{undefined <level>} | {noundefined}}
                             {{no}altdiagonal}
                             {{no}bentover} }
              unset hidden3d
              show hidden3d

        In contrast to the usual display in gnuplot, hidden line
        removal actually treats the given function or data grids as
        real surfaces that can't be seen through, so parts behind the
        surface will be hidden by it.  For this to be possible, the
        surface needs to have 'grid structure' (see sspplloott ddaattaaffiillee
        about this), and it has to be drawn wwiitthh lliinneess or wwiitthh lliinneess--
        ppooiinnttss.

        When hhiiddddeenn33dd is set, both the hidden portion of the surface
        and possibly its contours drawn on the base (see sseett ccoonnttoouurr)
        as well as the grid will be hidden.  Each surface has its hid-
        den parts removed with respect to itself and to other surfaces,
        if more than one surface is plotted.  Contours drawn on the
        surface (sseett ccoonnttoouurr ssuurrffaaccee) don't work.  Labels and arrows
        are always visible and are unaffected.  The key is also never
        hidden by the surface.

        Functions are evaluated at isoline intersections.  The algo-
        rithm interpolates linearly between function points or data
        points when determining the visible line segments.  This means
        that the appearance of a function may be different when plotted
        with hhiiddddeenn33dd than when plotted with nnoohhiiddddeenn33dd because in the
        latter case functions are evaluated at each sample.  Please see
        sseett ssaammpplleess and sseett iissoossaammpplleess for discussion of the differ-
        ence.

        The algorithm used to remove the hidden parts of the surfaces
        has some additional features controllable by this command.
        Specifying ddeeffaauullttss will set them all to their default set-
        tings, as detailed below.  If ddeeffaauullttss is not given, only
        explicitly specified options will be influenced: all others
        will keep their previous values, so you can turn on/off hidden
        line removal via sseett {{nnoo}}hhiiddddeenn33dd, without modifying the set of
        options you chose.

        The first option, ooffffsseett, influences the linestyle used for
        lines on the 'back' side.  Normally, they are drawn in a
        linestyle one index number higher than the one used for the
        front, to make the two sides of the surface distinguishable.
        You can specify a different line style offset to add instead of
        the default 1, by ooffffsseett <<ooffffsseett>>.  Option nnooooffffsseett stands for










   GNUPLOT 4.0                                                       94


        ooffffsseett 00, making the two sides of the surface use the same
        linestyle.

        Next comes the option ttrriiaanngglleeppaatttteerrnn <<bbiittppaatttteerrnn>>.  <bitpat-
        tern> must be a number between 0 and 7, interpreted as a bit
        pattern.  Each bit determines the visibility of one edge of the
        triangles each surface is split up into.  Bit 0 is for the
        'horizontal' edges of the grid, Bit 1 for the 'vertical' ones,
        and Bit 2 for the diagonals that split each cell of the origi-
        nal grid into two triangles.  The default pattern is 3, making
        all horizontal and vertical lines visible, but not the diago-
        nals.  You may want to choose 7 to see those diagonals as well.

        The uunnddeeffiinneedd <<lleevveell>> option lets you decide what the algorithm
        is to do with data points that are undefined (missing data, or
        undefined function values), or exceed the given x-, y- or z-
        ranges.  Such points can either be plotted nevertheless, or
        taken out of the input data set.  All surface elements touching
        a point that is taken out will be taken out as well, thus cre-
        ating a hole in the surface.  If <level> = 3, equivalent to
        option nnoouunnddeeffiinneedd, no points will be thrown away at all.  This
        may produce all kinds of problems elsewhere, so you should
        avoid this.  <level> = 2 will throw away undefined points, but
        keep the out-of-range ones.  <level> = 1, the default, will get
        rid of out-of-range points as well.

        By specifying nnooaallttddiiaaggoonnaall, you can override the default han-
        dling of a special case can occur if uunnddeeffiinneedd is active (i.e.
        <level> is not 3).  Each cell of the grid-structured input sur-
        face will be divided in two triangles along one of its diago-
        nals.  Normally, all these diagonals have the same orientation
        relative to the grid.  If exactly one of the four cell corners
        is excluded by the uunnddeeffiinneedd handler, and this is on the usual
        diagonal, both triangles will be excluded.  However if the
        default setting of aallttddiiaaggoonnaall is active, the other diagonal
        will be chosen for this cell instead, minimizing the size of
        the hole in the surface.

        The bbeennttoovveerr option controls what happens to another special
        case, this time in conjunction with the ttrriiaanngglleeppaatttteerrnn.  For
        rather crumply surfaces, it can happen that the two triangles a
        surface cell is divided into are seen from opposite sides (i.e.
        the original quadrangle is 'bent over'), as illustrated in the
        following ASCII art:

                                                                      C----B
            original quadrangle:  A--B      displayed quadrangle:
        |\   |
              ("set view 0,0")    | /|    ("set view 75,75" perhaps)  |
        \  |
                                  |/ |                                |
        \ |
                                  C--D                                |










   GNUPLOT 4.0                                                       95


        \|
                                                                      A
        D

        If the diagonal edges of the surface cells aren't generally
        made visible by bit 2 of the <bitpattern> there, the edge CB
        above wouldn't be drawn at all, normally, making the resulting
        display hard to understand.  Therefore, the default option of
        bbeennttoovveerr will turn it visible in this case.  If you don't want
        that, you may choose nnoobbeennttoovveerr instead.  See also hidden line
        removal demo (hidden.dem) and complex hidden line demo (sin-
        gulr.dem).



        3388..2266..  HHiissttoorryyssiizzee


        Note: the command sseett hhiissttoorryyssiizzee is only available when com-
        piled with the gnu readline.

        Syntax:
              set historysize <int>
              unset historysize

        When leaving gnuplot, the value of historysize is used for
        truncating the history to at most that much lines. The default
        is 500.  uunnsseett hhiissttoorryyssiizzee will disable history truncation and
        thus allow an infinite number of lines to be written to the
        history file.



        3388..2277..  IIssoossaammpplleess


        The isoline density (grid) for plotting functions as surfaces
        may be changed by the sseett iissoossaammpplleess command.

        Syntax:
              set isosamples <iso_1> {,<iso_2>}
              show isosamples

        Each function surface plot will have <iso_1> iso-u lines and
        <iso_2> iso-v lines.  If you only specify <iso_1>, <iso_2> will
        be set to the same value as <iso_1>.  By default, sampling is
        set to 10 isolines per u or v axis.  A higher sampling rate
        will produce more accurate plots, but will take longer.  These
        parameters have no effect on data file plotting.

        An isoline is a curve parameterized by one of the surface
        parameters while the other surface parameter is fixed.  Iso-
        lines provide a simple means to display a surface.  By fixing










   GNUPLOT 4.0                                                       96


        the u parameter of surface s(u,v), the iso-u lines of the form
        c(v) = s(u0,v) are produced, and by fixing the v parameter, the
        iso-v lines of the form c(u) = s(u,v0) are produced.

        When a function surface plot is being done without the removal
        of hidden lines, sseett ssaammpplleess  controls the number of points
        sampled along each isoline;  see sseett ssaammpplleess and sseett hhiiddddeenn33dd.
        The contour algorithm assumes that a function sample occurs at
        each isoline intersection, so change in ssaammpplleess as well as
        iissoossaammpplleess may be desired when changing the resolution of a
        function surface/contour.



        3388..2288..  KKeeyy


        The sseett kkeeyy enables a key (or legend) describing plots on a
        plot.

        The contents of the key, i.e., the names given to each plotted
        data set and function and samples of the lines and/or symbols
        used to represent them, are determined by the ttiittllee and wwiitthh
        options of the {ss}pplloott command.  Please see pplloott ttiittllee and pplloott
        wwiitthh for more information.

        Syntax:
              set key {on|off} {default}
                      {left | right | top | bottom | outside | below |
        <position>}
                      {Left | Right} {{no}reverse}
                      {samplen <sample_length>} {spacing <verti-
        cal_spacing>}
                      {width <width_increment>}
                      {height <height_increment>}
                      {{no}autotitles}
                      {title "<text>"} {{no}enhanced}
                      {{no}box { {linestyle | ls <line_style>}
                                 | {linetype | lt <line_type>}
                                   {linewidth | lw <line_width>}}}
              unset key
              show key

        By default the key is placed in the upper right corner of the
        graph.  The keywords lleefftt, rriigghhtt, ttoopp, bboottttoomm, oouuttssiiddee and
        bbeellooww may be used to place the key in the other corners inside
        the graph or to the right (outside) or below the graph.  They
        may be given alone or combined.

        Plots may be drawn with no visible key by requesting sseett kkeeyy
        ooffff or uunnsseett kkeeyy.

        Justification of the labels within the key is controlled by










   GNUPLOT 4.0                                                       97


        LLeefftt or RRiigghhtt (default is RRiigghhtt).  The text and sample can be
        reversed (rreevveerrssee) and a box can be drawn around the key (bbooxx
        {{......}}) in a specified lliinneettyyppee and lliinneewwiiddtthh, or a user-defined
        lliinneessttyyllee. Note that not all terminal drivers support linewidth
        selection, though.

        The length of the sample line can be controlled by ssaammpplleenn.
        The sample length is computed as the sum of the tic length and
        <sample_length> times the character width.  ssaammpplleenn also
        affects the positions of point samples in the key since these
        are drawn at the midpoint of the sample line, even if the sam-
        ple line itself is not drawn.

        The vertical spacing between lines is controlled by ssppaacciinngg.
        The spacing is set equal to the product of the pointsize, the
        vertical tic size, and <vertical_spacing>.  The program will
        guarantee that the vertical spacing is no smaller than the
        character height.

        The <width_increment> is a number of character widths to be
        added to or subtracted from the length of the string.  This is
        useful only when you are putting a box around the key and you
        are using control characters in the text.  ggnnuupplloott simply
        counts the number of characters in the string when computing
        the box width; this allows you to correct it.

        The <height_increment> is a number of character heights to be
        added to or subtracted from the height of the key box.  This is
        useful mainly when you are putting a box around the key, other-
        wise it can be used to adjust the vertical shift of automati-
        cally chosen key position by <height_increment>/2.

        All plotted curves of ppllootts and ssppllootts are titled according to
        the default option aauuttoottiittlleess. The automatic generation of
        titles can be suppressed by nnooaauuttoottiittlleess; then only those
        titles explicitly defined by ((ss))pplloott ...... ttiittllee ...... will be
        drawn.

        A title can be put on the key (ttiittllee ""<<tteexxtt>>"")---see also ssyynn--
        ttaaxx for the distinction between text in single- or double-
        quotes.  The key title uses the same justification as do the
        plot titles.

        An explicitly given title is typeset using enhanced text prop-
        erties on terminals supporting this, see eennhhaanncceedd tteexxtt for more
        details.  This default behavior can be switched off by the
        nnooeennhhaanncceedd option.

        The defaults for sseett kkeeyy are oonn, rriigghhtt, ttoopp, RRiigghhtt, nnoorreevveerrssee,
        ssaammpplleenn 44, ssppaacciinngg 11..2255, ttiittllee """", and nnoobbooxx.  The default
        <linetype> is the same as that used for the plot borders.
        Entering sseett kkeeyy ddeeffaauulltt returns the key to its default config-
        uration.










   GNUPLOT 4.0                                                       98


        The <position> can be a simple x,y,z as in previous versions,
        but these can be preceded by one of four keywords (ffiirrsstt, sseecc--
        oonndd, ggrraapphh, ssccrreeeenn) which selects the coordinate system in
        which the position of the first sample line is specified.  See
        ccoooorrddiinnaatteess for more details.

        The key is drawn as a sequence of lines, with one plot
        described on each line.  On the right-hand side (or the left-
        hand side, if rreevveerrssee is selected) of each line is a represen-
        tation that attempts to mimic the way the curve is plotted.  On
        the other side of each line is the text description (the line
        title), obtained from the pplloott command.  The lines are verti-
        cally arranged so that an imaginary straight line divides the
        left- and right-hand sides of the key.  It is the coordinates
        of the top of this line that are specified with the sseett kkeeyy
        command.  In a pplloott, only the x and y coordinates are used to
        specify the line position.  For a sspplloott, x, y and z are all
        used as a 3-d location mapped using the same mapping as the
        graph itself to form the required 2-d screen position of the
        imaginary line.

        Some or all of the key may be outside of the graph boundary,
        although this may interfere with other labels and may cause an
        error on some devices.  If you use the keywords oouuttssiiddee or
        bbeellooww, ggnnuupplloott makes space for the keys and the graph becomes
        smaller.  Putting keys outside to the right, they occupy as few
        columns as possible, and putting them below, as many columns as
        possible (depending of the length of the labels), thus stealing
        as little space from the graph as possible.

        When using the TeX or PostScript drivers, or similar drivers
        where formatting information is embedded in the string, ggnnuupplloott
        is unable to calculate correctly the width of the string for
        key positioning.  If the key is to be positioned at the left,
        it may be convenient to use the combination  sseett kkeeyy lleefftt LLeefftt
        rreevveerrssee.  The box and gap in the grid will be the width of the
        literal string.

        If sspplloott is being used to draw contours, the contour labels
        will be listed in the key.  If the alignment of these labels is
        poor or a different number of decimal places is desired, the
        label format can be specified.  See sseett ccllaabbeell for details.

        Examples:

        This places the key at the default location:
              set key default

        This disables the key:
              unset key

        This places a key at coordinates 2,3.5,2 in the default (first)
        coordinate system:










   GNUPLOT 4.0                                                       99


              set key 2,3.5,2

        This places the key below the graph:
              set key below

        This places the key in the bottom left corner, left-justifies
        the text, gives it a title, and draws a box around it in line-
        type 3:
              set key left bottom Left title 'Legend' box 3



        3388..2299..  LLaabbeell


        Arbitrary labels can be placed on the plot using the sseett llaabbeell
        command.

        Syntax:
              set label {<tag>}
                        { {"<label text>"{,<value>}} {, ...}} }
                        {at <position>}
                        {left | center | right}
                        {norotate | rotate {by <degrees>}}
                        {font "<name>{,<size>}"}
                        {front | back}
                        {textcolor <colorspec>}
                        {point <pointstyle> {offset x, y} | nopoint}
              unset label {<tag>}
              show label

        The <position> is specified by either x,y or x,y,z, and may be
        preceded by ffiirrsstt, sseeccoonndd, ggrraapphh, or ssccrreeeenn to select the coor-
        dinate system.  See ccoooorrddiinnaatteess for details.

        The tag is an integer that is used to identify the label. If no
        <tag> is given, the lowest unused tag value is assigned auto-
        matically.  The tag can be used to delete or modify a specific
        label.  To change any attribute of an existing label, use the
        sseett llaabbeell command with the appropriate tag, and specify the
        parts of the label to be changed.

        The <label text> can optionally contain numbers, generated by
        replacement of printf()-like format specifiers contained in
        <label text>.  The number to be used is given by the <value>
        following the text.  The same formatting capabilities as for
        tic labels are available.  See the help on ffoorrmmaatt ssppeecciiffiieerrss
        for details. To display more than one distinct <value> with a
        single label, several pairs of <label text> and <value> may be
        given. Note that <value> is treated as a constant expression,
        i.e. if it contains variables, the label text will not change
        if the variable values are modified, later on.  The sseett ddeeccii--
        mmaallssiiggnn option, if active, overrides the decimal separator










   GNUPLOT 4.0                                                      100


        character of numbers entered into label texts.

        By default, the text is placed flush left against the point
        x,y,z.  To adjust the way the label is positioned with respect
        to the point x,y,z, add the justification parameter, which may
        be lleefftt, rriigghhtt or cceenntteerr, indicating that the point is to be at
        the left, right or center of the text.  Labels outside the
        plotted boundaries are permitted but may interfere with axis
        labels or other text.

        If rroottaattee is given, the label is written vertically (if the
        terminal can do so, of course).  If rroottaattee bbyy <<ddeeggrreeeess>> is
        given, conforming terminals will try to write the text at the
        specified angle; non-conforming terminals will treat this as
        vertical text.

        Font and its size can be chosen explicitly by ffoonntt
        ""<<nnaammee>>{{,,<<ssiizzee>>}}"" if the terminal supports font settings.  Oth-
        erwise the default font of the terminal will be used.

        If ffrroonntt is given, the label is written on top of the graphed
        data. If bbaacckk is given (the default), the label is written
        underneath the graphed data.  Using ffrroonntt will prevent a label
        from being obscured by dense data.

        TTeexxttccoolloorr <<ccoolloorrssppeecc>> changes the color of the label text.
        <<ccoolloorrssppeecc>> is either a linetype or a mapping onto the pm3d
        color palette (available only in sspplloott), see help for sseett
        ppaalleettttee.
           `textcolor` may be abbreviated `tc`.
           `tc default` resets the text color to its default state.
           `tc lt <n>` sets the text color to that of line type <n>.
           `tc palette z` selects a palette color corresponding to the
        label z position.
           `tc palette cb <val>` selects a color corresponding to <val>
        on the colorbar.
           `tc palette fraction <val>`, with 0<=val<=1, selects a color
        corresponding to
               the mapping [0:1] to grays/colors of the `palette`.

        If a <pointstyle> is given, using keywords lltt, pptt and ppss, see
        ssttyyllee, a point with the given style and color of the given line
        type is plotted at the label position and the text of the label
        is displaced slightly.  The displacement defaults to 1, 1 in
        ppooiinnttssiizzee units and can be controlled by the optional ooffffsseett xx,,
        yy. Example: ooffffsseett 22,, --33 would displace the labels 2 * point-
        size horizontally and -3 * pointsize vertically from the actual
        coordinate point as given by ppoossiittiioonn.  The size of the point
        depends also on the setting of ppooiinnttssiizzee.  This option is used
        by default for placing labels in mmoouussee enhanced terminals.  Use
        nnooppooiinntt to turn off the drawing of a point near the label (this
        is the default).











   GNUPLOT 4.0                                                      101


        If one (or more) axis is timeseries, the appropriate coordinate
        should be given as a quoted time string according to the
        ttiimmeeffmmtt format string.  See sseett xxddaattaa and sseett ttiimmeeffmmtt.

        The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string
        to specify a newline.

        Examples:

        To set a label at (1,2) to "y=x", use:
              set label "y=x" at 1,2

        To set a Sigma of size 24, from the Symbol font set, at the
        center of the graph, use:
              set label "S" at graph 0.5,0.5 center font "Symbol,24"

        To set a label "y=x^2" with the right of the text at (2,3,4),
        and tag the label as number 3, use:
              set label 3 "y=x^2" at 2,3,4 right

        To change the preceding label to center justification, use:
              set label 3 center

        To delete label number 2, use:
              unset label 2

        To delete all labels, use:
              unset label

        To show all labels (in tag order), use:
              show label

        To set a label on a graph with a timeseries on the x axis, use,
        for example:
              set timefmt "%d/%m/%y,%H:%M"
              set label "Harvest" at "25/8/93",1

        To display a freshly fitted parameter on the plot with the data
        and the fitted function, do this after the ffiitt, but before the
        pplloott:
              set label 'a = %3.5g',par_a     at 30, 15
              set label 'b = %s*10^%S',par_b  at 30, 20

        To set a label displaced a little bit from a small point:
              set label 'origin' at 0,0 point lt 1 pt 2 ps 3 offset
        1,-1

        To set a label whose color matches the z value (in this case
        5.5) of some point on a 3D splot colored using pm3d:
              set label 'text' at 0,0,5.5 tc palette z













   GNUPLOT 4.0                                                      102


        3388..3300..  LLmmaarrggiinn


        The command sseett llmmaarrggiinn sets the size of the left margin.
        Please see sseett mmaarrggiinn for details.



        3388..3311..  LLooaaddppaatthh


        The llooaaddppaatthh setting defines additional locations for data and
        command files searched by the ccaallll, llooaadd, pplloott and sspplloott com-
        mands.  If a file cannot be found in the current directory, the
        directories in llooaaddppaatthh are tried.

        Syntax:
              set loadpath {"pathlist1" {"pathlist2"...}}
              show loadpath

        Path names may be entered as single directory names, or as a
        list of path names separated by a platform-specific path sepa-
        rator, eg. colon (':') on Unix, semicolon (';') on DOS/Win-
        dows/OS/2/Amiga platforms.  The sshhooww llooaaddppaatthh, ssaavvee and ssaavvee
        sseett commands replace the platform-specific separator with a
        space character (' ') for maximum portability.

        If the environment variable GNUPLOT_LIB is set, its contents
        are appended to llooaaddppaatthh.  However, sshhooww llooaaddppaatthh prints the
        contents of user defined loadpath and system loadpath sepa-
        rately.  Also, the ssaavvee and ssaavvee sseett commands save only the
        user specified parts of llooaaddppaatthh, for portability reasons.



        3388..3322..  LLooccaallee


        The llooccaallee setting determines the language with which
        {{xx,,yy,,zz}}{{dd,,mm}}ttiiccss will write the days and months.

        Syntax:
              set locale {"<locale>"}

        <locale> may be any language designation acceptable to your
        installation.  See your system documentation for the available
        options.  The default value is determined from the LANG envi-
        ronment variable.















   GNUPLOT 4.0                                                      103


        3388..3333..  LLooggssccaallee


        Log scaling may be set on the x, y, z, x2 and/or y2 axes.

        Syntax:
              set logscale <axes> <base>
              unset logscale <axes>
              show logscale

        where <axes> may be any combinations of xx, yy, zz, and ccbb in any
        order, or xx22 or yy22 and where <base> is the base of the log
        scaling.  If <base> is not given, then 10 is assumed.  If
        <axes> is not given, then all axes are assumed.  uunnsseett llooggssccaallee
        turns off log scaling for the specified axes.

        Examples:

        To enable log scaling in both x and z axes:
              set logscale xz

        To enable scaling log base 2 of the y axis:
              set logscale y 2

        To enable z and color log axes for a pm3d plot:
              set logscale zcb

        To disable z axis log scaling:
              unset logscale z



        3388..3344..  MMaappppiinngg


        If data are provided to sspplloott in spherical or cylindrical coor-
        dinates, the sseett mmaappppiinngg command should be used to instruct
        ggnnuupplloott how to interpret them.

        Syntax:
              set mapping {cartesian | spherical | cylindrical}

        A cartesian coordinate system is used by default.

        For a spherical coordinate system, the data occupy two or three
        columns (or uussiinngg entries).  The first two are interpreted as
        the azimuthal and polar angles theta and phi (or "longitude"
        and "latitude"), in the units specified by sseett aanngglleess.  The
        radius r is taken from the third column if there is one, or is
        set to unity if there is no third column.  The mapping is:

              x = r * cos(theta) * cos(phi)
              y = r * sin(theta) * cos(phi)










   GNUPLOT 4.0                                                      104


              z = r * sin(phi)

        Note that this is a "geographic" spherical system, rather than
        a "polar" one (that is, phi is measured from the equator,
        rather than the pole).

        For a cylindrical coordinate system, the data again occupy two
        or three columns.  The first two are interpreted as theta (in
        the units specified by sseett aanngglleess) and z.  The radius is either
        taken from the third column or set to unity, as in the spheri-
        cal case.  The mapping is:

              x = r * cos(theta)
              y = r * sin(theta)
              z = z

        The effects of mmaappppiinngg can be duplicated with the uussiinngg filter
        on the sspplloott command, but mmaappppiinngg may be more convenient if
        many data files are to be processed.  However even if mmaappppiinngg
        is used, uussiinngg may still be necessary if the data in the file
        are not in the required order.

        mmaappppiinngg has no effect on pplloott.  world.dem: mapping demos.



        3388..3355..  MMaarrggiinn


        The computed margins can be overridden by the sseett mmaarrggiinn com-
        mands.  sshhooww mmaarrggiinn shows the current settings.

        Syntax:
              set bmargin {<margin>}
              set lmargin {<margin>}
              set rmargin {<margin>}
              set tmargin {<margin>}
              show margin

        The units of <margin> are character heights or widths, as
        appropriate.  A positive value defines the absolute size of the
        margin.  A negative value (or none) causes ggnnuupplloott to revert to
        the computed value.  For 3D plots, only the left margin setting
        has any effect so far.

        Normally the margins of a plot are automatically calculated
        based on tics, tic labels, axis labels, the plot title, the
        timestamp and the size of the key if it is outside the borders.
        If, however, tics are attached to the axes (sseett xxttiiccss aaxxiiss, for
        example), neither the tics themselves nor their labels will be
        included in either the margin calculation or the calculation of
        the positions of other text to be written in the margin.  This
        can lead to tic labels overwriting other text if the axis is










   GNUPLOT 4.0                                                      105


        very close to the border.



        3388..3366..  MMoouussee


        The command sseett mmoouussee enables mouse actions. Currently the pm,
        x11, ggi and windows terminals are mouse enhanced. There are
        two mouse modes. The 2d-graph mode works for 2d graphs and for
        maps (i.e. splots with sseett vviieeww having z-rotation 0, 90, 180,
        270 or 360 degrees) and it allows tracing the position over
        graph, zooming, annotating graph etc. For 3d graphs sspplloott, the
        view and scaling of the graph can be changed with mouse buttons
        1 and 2. If additionally to these buttons the modifier <ctrl>
        is hold down, the coordinate system only is rotated which is
        useful for large data sets. A vertical motion of Button 2 with
        the shift key hold down changes the ticslevel.

        Mousing is not available in multiplot mode. If multiplot is
        disabled using uunnsseett mmuullttiipplloott though,  the mouse will be
        turned on again and acts on the last plot (like replot does).

        Syntax:
              set mouse [doubleclick <ms>] [nodoubleclick] \
                        [[no]zoomcoordinates] \
                        [[no]polardistance] \
                        [format <string>] \
                        [clipboardformat <int>/<string>] \
                        [mouseformat <int>/<string>] \
                        [[no]labels] [labeloptions <string>] \
                        [[no]zoomjump] [[no]verbose]
              unset mouse

        The doubleclick resolution is given in milliseconds and used
        for Button 1 which copies the current mouse position to the
        cclliippbbooaarrdd. If you want that to be done by single clicking a
        value of 0 ms can be used. The default value is 300 ms.

        The option zzoooommccoooorrddiinnaatteess determines if the coordinates of the
        zoom box are drawn at the edges while zooming. This is on by
        default.

        The option ppoollaarrddiissttaannccee determines if the distance to the
        ruler is also shown in polar coordinates. This corresponds to
        the default key binding '5'.

        The ffoorrmmaatt option takes a fprintf like format string which
        determines how floating point numbers are printed to the driv-
        ers window and the clipboard.  The default is "% #g".

        cclliippbbooaarrddffoorrmmaatt and mmoouusseeffoorrmmaatt are used for formatting the
        text on Button1 and Button2 actions -- copying the coordinates










   GNUPLOT 4.0                                                      106


        to the clipboard and temporarily annotating the mouse position.
        This corresponds to the key bindings '1', '2', '3', '4' (see
        the drivers's help window). If the argument is a string this
        string is used as c format specifier and should contain two
        float specifiers, e.g. sseett mmoouussee mmoouusseeffoorrmmaatt ""mmoouussee == %%55..22gg,,
        %%1100..22ff"". Use sseett mmoouussee mmoouusseeffoorrmmaatt """" to turn this string off
        again.

        The following formats are available (format 6 may only be
        selected if the format string was specified already):

         0   real coordinates in  brackets e.g. [1.23, 2.45]
         1   real coordinates w/o brackets e.g.  1.23, 2.45
         2   x == timefmt                       [(as set by `set
        timefmt`), 2.45]
         3   x == date                          [31. 12. 1999, 2.45]
         4   x == time                          [23:59, 2.45]
         5   x == date / time                   [31. 12. 1999 23:59,
        2.45]
         6   alt. format, specified as string   ""

        Choose the option llaabbeellss to get real gnuplot labels on Button
        2. (The default is nnoollaabbeellss which makes Button 2 drawing only
        temporary annotations at the mouse positions). The labels are
        drawn with the current setting of mmoouusseeffoorrmmaatt. llaabbeellooppttiioonnss
        controls which options are passed to the sseett llaabbeell command. The
        default is "pointstyle 1" which will plot a small plus at the
        label position.  Note that the pointsize is taken from the sseett
        ppooiinnttssiizzee command.  Labels can be removed by holding the Ctrl-
        Key down while clicking with Button 2 on the label's point. The
        threshold for how close you must be to the label is also deter-
        mined by the ppooiinnttssiizzee.

        If the option zzoooommjjuummpp is on, the mouse pointer will be auto-
        matically offset a small distance after starting a zoom region
        with button 3. This can be useful to avoid a tiny (or even
        empty) zoom region. zzoooommjjuummpp is off by default.

        If the option vveerrbboossee is turned on the communication commands
        are shown during execution. This option can also be toggled by
        hitting 66 in the driver's window. vveerrbboossee is off by default.

        Press 'h' in the driver's window for a short summary of the
        mouse and key bindings.  This will also display user defined
        bindings or hhoottkkeeyyss which can be defined using the bbiinndd com-
        mand, see help for bbiinndd.  Note, that user defined hhoottkkeeyyss may
        override the default bindings.

        Press 'q' in the driver's window to close the window. This key
        cannot be overridden with the bbiinndd command.

        See also help for bbiinndd and llaabbeell.











   GNUPLOT 4.0                                                      107


             3388..3366..11..  XX1111__mmoouussee


             X11 mouse support is turned on by default if standard
             input comes from a terminal (tty). Mouse support is turned
             off if standard input does not come from a tty, e.g. a
             pipe. If you want to use mouse support while writing to
             gnuplot from a pipe, the mouse must be turned on *before*
             starting the x11 driver, e.g. immediately after startup
             with the explicit command sseett mmoouussee.  Beware: on some UNIX
             flavours, special input devices as /dev/null might not be
             sseelleecctt--aabbllee; turning on the mouse when using such devices
             will hang gnuplot.

             If multiple X11 plot windows have been opened using the
             sseett tteerrmm xx1111 <<nn>> terminal option, then only the current
             plot window supports the entire range of mouse commands
             and hotkeys.  The other windows will, however, continue to
             display mouse coordinates at the lower left.



        3388..3377..  MMuullttiipplloott


        The command sseett mmuullttiipplloott places ggnnuupplloott in the multiplot mode,
        in which several plots are placed on the same page, window, or
        screen.

        Syntax:
              set multiplot
              unset multiplot

        For some terminals, no plot is displayed until the command
        uunnsseett mmuullttiipplloott is given, which causes the entire page to be
        drawn and then returns ggnnuupplloott to its normal single-plot mode.
        For other terminals, each separate pplloott command produces a
        plot, but the screen may not be cleared between plots.

        Any labels or arrows that have been defined will be drawn for
        each plot according to the current size and origin (unless
        their coordinates are defined in the ssccrreeeenn system).  Just
        about everything else that can be sseett is applied to each plot,
        too.  If you want something to appear only once on the page,
        for instance a single time stamp, you'll need to put a sseett
        ttiimmee/uunnsseett ttiimmee pair around one of the pplloott, sspplloott or rreepplloott
        commands within the sseett mmuullttiipplloott/uunnsseett mmuullttiipplloott block.

        The commands sseett oorriiggiinn and sseett ssiizzee must be used to correctly
        position each plot; see sseett oorriiggiinn and sseett ssiizzee for details of
        their usage.

        Example:










   GNUPLOT 4.0                                                      108


              set size 0.7,0.7
              set origin 0.1,0.1
              set multiplot
              set size 0.4,0.4
              set origin 0.1,0.1
              plot sin(x)
              set size 0.2,0.2
              set origin 0.5,0.5
              plot cos(x)
              unset multiplot

        displays a plot of cos(x) stacked above a plot of sin(x).  Note
        the initial sseett ssiizzee and sseett oorriiggiinn.  While these are not
        always required, their inclusion is recommended.  Some terminal
        drivers require that bounding box information be available
        before any plots can be made, and the form given above guaran-
        tees that the bounding box will include the entire plot array
        rather than just the bounding box of the first plot.

        sseett ssiizzee and sseett oorriiggiinn refer to the entire plotting area used
        for each plot.  If you want to have the axes themselves line
        up, you can guarantee that the margins are the same size with
        the sseett mmaarrggiinn commands.  See sseett mmaarrggiinn for their use.  Note
        that the margin settings are absolute, in character units, so
        the appearance of the graph in the remaining space will depend
        on the screen size of the display device, e.g., perhaps quite
        different on a video display and a printer.  See also multiplot
        demo (multiplt.dem).



        3388..3388..  MMxx22ttiiccss


        Minor tic marks along the x2 (top) axis are controlled by sseett
        mmxx22ttiiccss.  Please see sseett mmxxttiiccss.



        3388..3399..  MMxxttiiccss


        Minor tic marks along the x axis are controlled by sseett mmxxttiiccss.
        They can be turned off with uunnsseett mmxxttiiccss.  Similar commands
        control minor tics along the other axes.

        Syntax:
              set mxtics {<freq> | default}
              unset mxtics
              show mxtics

        The same syntax applies to mmyyttiiccss, mmzzttiiccss, mmxx22ttiiccss, mmyy22ttiiccss and
        mmccbbttiiccss.










   GNUPLOT 4.0                                                      109


        <freq> is the number of sub-intervals (NOT the number of minor
        tics) between major tics (the default for a linear axis is
        either two or five depending on the major tics, so there are
        one or four minor tics between major tics). Selecting ddeeffaauulltt
        will return the number of minor ticks to its default value.

        If the axis is logarithmic, the number of sub-intervals will be
        set to a reasonable number by default (based upon the length of
        a decade).  This will be overridden if <freq> is given.  How-
        ever the usual minor tics (2, 3, ..., 8, 9 between 1 and 10,
        for example) are obtained by setting <freq> to 10, even though
        there are but nine sub-intervals.

        Minor tics can be used only with uniformly spaced major tics.
        Since major tics can be placed arbitrarily by sseett
        {{xx||xx22||yy||yy22||zz}}ttiiccss, minor tics cannot be used if major tics are
        explicitly sseett.

        By default, minor tics are off for linear axes and on for loga-
        rithmic axes.  They inherit the settings for aaxxiiss||bboorrddeerr and
        {{nnoo}}mmiirrrroorr specified for the major tics.  Please see sseett xxttiiccss
        for information about these.



        3388..4400..  MMyy22ttiiccss


        Minor tic marks along the y2 (right-hand) axis are controlled
        by sseett mmyy22ttiiccss.  Please see sseett mmxxttiiccss.



        3388..4411..  MMyyttiiccss


        Minor tic marks along the y axis are controlled by sseett mmyyttiiccss.
        Please see sseett mmxxttiiccss.



        3388..4422..  MMzzttiiccss


        Minor tic marks along the z axis are controlled by sseett mmzzttiiccss.
        Please see sseett mmxxttiiccss.



        3388..4433..  OOffffsseettss













   GNUPLOT 4.0                                                      110


        Offsets provide a mechanism to put a boundary around the data
        inside of an autoscaled graph.

        Syntax:
              set offsets <left>, <right>, <top>, <bottom>
              unset offsets
              show offsets

        Each offset may be a constant or an expression.  Each defaults
        to 0.  Left and right offsets are given in units of the x axis,
        top and bottom offsets in units of the y axis.  A positive off-
        set expands the graph in the specified direction, e.g., a posi-
        tive bottom offset makes ymin more negative.  Negative offsets,
        while permitted, can have unexpected interactions with
        autoscaling and clipping.

        Offsets are ignored in ssppllootts.

        Example:
              set offsets 0, 0, 2, 2
              plot sin(x)

        This graph of sin(x) will have a y range [-3:3] because the
        function will be autoscaled to [-1:1] and the vertical offsets
        are each two.



        3388..4444..  OOrriiggiinn


        The sseett oorriiggiinn command is used to specify the origin of a plot-
        ting surface (i.e., the graph and its margins) on the screen.
        The coordinates are given in the ssccrreeeenn coordinate system (see
        ccoooorrddiinnaatteess for information about this system).

        Syntax:
              set origin <x-origin>,<y-origin>



        3388..4455..  OOuuttppuutt


        By default, screens are displayed to the standard output. The
        sseett oouuttppuutt command redirects the display to the specified file
        or device.

        Syntax:
              set output {"<filename>"}
              show output

        The filename must be enclosed in quotes.  If the filename is










   GNUPLOT 4.0                                                      111


        omitted, any output file opened by a previous invocation of sseett
        oouuttppuutt will be closed and new output will be sent to STDOUT.
        (If you give the command sseett oouuttppuutt ""SSTTDDOOUUTT"", your output may
        be sent to a file named "STDOUT"!  ["May be", not "will be",
        because some terminals, like xx1111, ignore sseett oouuttppuutt.])

        MSDOS users should note that the \ character has special sig-
        nificance in double-quoted strings, so single-quotes should be
        used for filenames in different directories.

        When both sseett tteerrmmiinnaall and sseett oouuttppuutt are used together, it is
        safest to give sseett tteerrmmiinnaall first, because some terminals set a
        flag which is needed in some operating systems.  This would be
        the case, for example, if the operating system needs to know
        whether or not a file is to be formatted in order to open it
        properly.

        On machines with popen functions (Unix), output can be piped
        through a shell command if the first non-whitespace character
        of the filename is '|'.  For instance,

              set output "|lpr -Plaser filename"
              set output "|lp -dlaser filename"

        On MSDOS machines, sseett oouuttppuutt ""PPRRNN"" will direct the output to
        the default printer.  On VMS, output can be sent directly to
        any spooled device.  It is also possible to send the output to
        DECnet transparent tasks, which allows some flexibility.



        3388..4466..  PPaarraammeettrriicc


        The sseett ppaarraammeettrriicc command changes the meaning of pplloott (sspplloott)
        from normal functions to parametric functions.  The command
        uunnsseett ppaarraammeettrriicc restores the plotting style to normal, single-
        valued expression plotting.

        Syntax:
              set parametric
              unset parametric
              show parametric

        For 2-d plotting, a parametric function is determined by a pair
        of parametric functions operating on a parameter.  An example
        of a 2-d parametric function would be pplloott ssiinn((tt)),,ccooss((tt)), which
        draws a circle (if the aspect ratio is set correctly---see sseett
        ssiizzee).  ggnnuupplloott will display an error message if both functions
        are not provided for a parametric pplloott.

        For 3-d plotting, the surface is described as x=f(u,v),
        y=g(u,v), z=h(u,v).  Therefore a triplet of functions is










   GNUPLOT 4.0                                                      112


        required.  An example of a 3-d parametric function would be
        ccooss((uu))**ccooss((vv)),,ccooss((uu))**ssiinn((vv)),,ssiinn((uu)), which draws a sphere.  ggnnuu--
        pplloott will display an error message if all three functions are
        not provided for a parametric sspplloott.

        The total set of possible plots is a superset of the simple
        f(x) style plots, since the two functions can describe the x
        and y values to be computed separately.  In fact, plots of the
        type t,f(t) are equivalent to those produced with f(x) because
        the x values are computed using the identity function.  Simi-
        larly, 3-d plots of the type u,v,f(u,v) are equivalent to
        f(x,y).

        Note that the order the parametric functions are specified is
        xfunction, yfunction (and zfunction) and that each operates
        over the common parametric domain.

        Also, the sseett ppaarraammeettrriicc function implies a new range of val-
        ues.  Whereas the normal f(x) and f(x,y) style plotting assume
        an xrange and yrange (and zrange), the parametric mode addi-
        tionally specifies a trange, urange, and vrange.  These ranges
        may be set directly with sseett ttrraannggee, sseett uurraannggee, and sseett
        vvrraannggee, or by specifying the range on the pplloott or sspplloott com-
        mands.  Currently the default range for these parametric vari-
        ables is [-5:5].  Setting the ranges to something more meaning-
        ful is expected.



        3388..4477..  PPlloott


        The sshhooww pplloott command shows the current plotting command as it
        results from the last pplloott and/or sspplloott and possible subsequent
        rreepplloott commands.

        In addition, the sshhooww pplloott aadddd22hhiissttoorryy command adds this cur-
        rent plot command into the hhiissttoorryy. It is useful if you have
        used rreepplloott to add more curves to the current plot and you want
        to edit the whole command now.



        3388..4488..  PPmm33dd


        pm3d is an sspplloott style for drawing palette-mapped 3d and 4d
        data as color/gray maps and surfaces.  It uses a pm3d algorithm
        which allows plotting gridded as well as non-gridded data with-
        out preprocessing, even when the data scans do not have the
        same number of points.

        Drawing of color surfaces is available on terminals supporting










   GNUPLOT 4.0                                                      113


        filled colored polygons with color mapping specified by
        ppaalleettttee. Currently supported terminals include

          Screen terminals:
            OS/2 Presentation Manager
            X11
            Linux VGA (vgagl)
            GGI
            Windows
            AquaTerm (Mac OS X)
          Files:
            PostScript
            pslatex, pstex, epslatex
            gif, png, jpeg
            (x)fig
            tgif
            cgm
            pdf
            svg

        Let us first describe how a map/surface is drawn.  The input
        data come from an evaluated function or from an sspplloott ddaattaa
        ffiillee.  Each surface consists of a sequence of separate scans
        (isolines).  The pm3d algorithm fills the region between two
        neighbouring points in one scan with another two points in the
        next scan by a gray (or color) according to z-values (or
        according to an additional 'color' column, see help for uussiinngg)
        of these 4 corners; by default the 4 corner values are aver-
        aged, but this can be changed by the option ccoorrnneerrss22ccoolloorr.  In
        order to get a reasonable surface, the neighbouring scans
        should not cross and the number of points in the neighbouring
        scans should not differ too much; of course, the best plot is
        with scans having same number of points.  There are no other
        requirements (e.g. the data need not be gridded).  Another
        advantage is that the pm3d algorithm does not draw anything
        outside of the input (measured or calculated) region.

        Surface coloring works with the following input data:

        1. splot of function or of data file with one or three data
        columns: The gray/color scale is obtained by mapping the aver-
        aged (or ccoorrnneerrss22ccoolloorr) z-coordinate of the four corners of the
        above-specified quadrangle into the range
        [min_color_z,max_color_z] of zzrraannggee or ccbbrraannggee providing a gray
        value in the range [0:1].  This value can be used directly as
        the gray for gray maps.  The normalized gray value can be fur-
        ther mapped into a color---see sseett ppaalleettttee for the complete
        description.

        2. splot of data file with two or four data columns: The
        gray/color value is obtained by using the last-column coordi-
        nate instead of the z-value, thus allowing the color and the z-
        coordinate be mutually independent.  This can be used for 4d










   GNUPLOT 4.0                                                      114


        data drawing.

        Other notes:

        1. The term 'scan' referenced above is used more among physi-
        cists than the term 'iso_curve' referenced in gnuplot documen-
        tation and sources.  You measure maps recorded one scan after
        another scan, that's why.

        2. The 'gray' or 'color' scale is a linear mapping of a contin-
        uous variable onto a smoothly varying palette of colors. The
        mapping is shown in a rectangle next to the main plot. This
        documentation refers to this as a "colorbox", and refers to the
        indexing variable as lying on the colorbox axis.  See sseett ccooll--
        oorrbbooxx, sseett ccbbrraannggee.

        3. To use pm3d coloring to generate a two-dimensional plot
        rather than a 3D surface, use sseett vviieeww mmaapp or sseett ppmm33dd mmaapp.

        Syntax:
              set pm3d
              set pm3d {
                         { at <bst combination> }
                         { scansautomatic | scansforward | scansback-
        ward }
                         { flush { begin | center | end } }
                         { ftriangles | noftriangles }
                         { clip1in | clip4in }
                         { corners2color {
        mean|geomean|median|c1|c2|c3|c4 } }
                         { hidden3d <linestyle> | nohidden3d }
                         { implicit | explicit }
                         { map }
                       }
              show pm3d
              unset pm3d

        Setting sseett ppmm33dd (i.e. without options) sets up the default
        values.  Otherwise, the options can be given in any order.

        Color surface can be drawn at the base or top (then it is a
        gray/color planar map) or at z-coordinates of surface points
        (gray/color surface).  This is defined by the aatt option with a
        string of up to 6 combinations of bb, tt and ss. For instance, aatt
        bb plots at bottom only, aatt sstt plots firstly surface and then
        top map, while aatt bbssttbbsstt will never by seriously used.

        Colored quadrangles are plotted one after another.  When plot-
        ting surfaces (aatt ss), the later quadrangles overlap (overdraw)
        the previous ones.  (Gnuplot is not virtual reality tool to
        calculate intersections of filled polygon meshes.)  You may try
        to switch between ssccaannssffoorrwwaarrdd and ssccaannssbbaacckkwwaarrdd to force the
        first scan of the data to be plotted first or last.  The










   GNUPLOT 4.0                                                      115


        default is ssccaannssaauuttoommaattiicc where gnuplot makes a guess about
        scans order.

        If two subsequent scans do not have same number of points, then
        it has to be decided whether to start taking points for quad-
        rangles from the beginning of both scans (fflluusshh bbeeggiinn), from
        their ends (fflluusshh eenndd) or to center them (fflluusshh cceenntteerr).  Note,
        that fflluusshh ((cceenntteerr||eenndd)) are incompatible with ssccaannssaauuttoommaattiicc:
        if you specify fflluusshh cceenntteerr or fflluusshh eenndd and ssccaannssaauuttoommaattiicc is
        set, it is silently switched to ssccaannssffoorrwwaarrdd.

        If two subsequent scans do not have the same number of points,
        the option ffttrriiaanngglleess specifies whether color triangles are
        drawn at the scan tail(s) where there are not enough points in
        either of the scan. This can be used to draw a smooth map
        boundary.

        Clipping with respect to x, y coordinates of quadrangles can be
        done in two ways.  cclliipp11iinn: all 4 points of each quadrangle
        must be defined and at least 1 point of the quadrangle must lie
        in the x and y ranges.  cclliipp44iinn: all 4 points of each quadran-
        gle must lie in the x and y ranges.

        There is a single gray/color value associated to each drawn
        pm3d quadrangle (no smooth color change among vertices).  The
        value is calculated from z-coordinates from the surrounding
        corners according to ccoorrnneerrss22ccoolloorr <<ooppttiioonn>>.  The options
        'mean' (default), 'geomean' and 'median' produce various kinds
        of surface color smoothing.  This may not be desired for pixel
        images or for maps with sharp and intense peaks, in which case
        the options 'c1', 'c2', 'c3' or 'c4' can be used instead to
        assign the quadrangle color based on the z-coordinate of only
        one corner.  Some experimentation may be needed to determine
        which corner corresponds to 'c1', as the orientation depends on
        the drawing direction.  Because the pm3d algorithm does not
        extend the colored surface outside the range of the input data
        points, the 'c<j>' coloring options will result in pixels along
        two edges of the grid not contributing to the color of any
        quadrangle.  For example, applying the pm3d algorithm to the
        4x4 grid of data points in script ddeemmoo//ppmm33dd..ddeemm (please have a
        look) produces only (4-1)x(4-1)=9 colored rectangles.

        Another drawing algorithm, which would draw quadrangles around
        a given node by taking corners from averaged (x,y)-coordinates
        of its surrounding 4 nodes while using node's color, could be
        implemented in the future.

        Notice that ranges of z-values and color-values for surfaces
        are adjustable independently by sseett zzrraannggee, sseett ccbbrraannggee, as
        well as sseett lloogg for z or cb.  Maps can be adjusted by the cb-
        axis only; see also sseett vviieeww mmaapp and sseett ccoolloorrbbooxx.

        The option hhiiddddeenn33dd takes as the argument a linestyle which










   GNUPLOT 4.0                                                      116


        must be created by sseett ssttyyllee lliinnee ....... (The style need not to
        be present when setting pm3d, but it must be present when plot-
        ting).  If set, lines are drawn using the specified line style,
        taking into account hidden line removal.  This is by far more
        efficient than using the command sseett hhiiddddeenn33dd as it doesn't
        really calculate hidden line removal, but just draws the filled
        polygons in the correct order. So the recommended choice when
        using pm3d is
              set pm3d at s hidden3d 100
              set style line 100 lt 5 lw 0.5
              unset hidden3d
              unset surf
              splot x*x+y*y

        There used to be an option {transparent|solid} to this command.
        Now you get the same effect from sseett ggrriidd {{ffrroonntt||llaayyeerrddeeffaauulltt}},
        respectively.

        The sseett ppmm33dd mmaapp is an abbreviation for sseett ppmm33dd aatt bb; sseett vviieeww
        mmaapp; sseett ssttyyllee ddaattaa ppmm33dd; sseett ssttyyllee ffuunncc ppmm33dd;.  It is used for
        backwards compatibility, when sseett vviieeww mmaapp was not available.
        Take care that you properly use zzrraannggee and ccbbrraannggee for input
        data point filtering and color range scaling, respectively; and
        also sseett ((nnoo))ssuurrffaaccee seems to have a (side?) effect.

        The coloring setup as well as the color box drawing are deter-
        mined by sseett ppaalleettttee.  There can be only one palette for the
        current plot.  Drawing of several surfaces with different
        palettes can be achieved by mmuullttiipplloott with fixed oorriiggiinn and
        ssiizzee; don't forget to use sseett ppaalleettttee mmaaxxccoolloorrss when your ter-
        minal is running out of available colors.

        If the option iimmpplliicciitt is on (which is the default), all sur-
        face plots will be plotted additionally to the default type,
        e.g.
              splot 'fred.dat' with lines, 'lola.dat' with lines
        would give both plots additionally to a pm3d surface.  If the
        option iimmpplliicciitt is off (or eexxpplliicciitt is on) only plots specified
        by the wwiitthh ppmm33dd attribute are plotted with a pm3d surface,
        e.g.:
              splot 'fred.dat' with lines, 'lola.dat' with pm3d
        would plot 'fred.dat' with lines (and only lines) and
        'lola.dat' with a pm3d surface.  If eexxpplliicciitt is on, you can
        also switch to the default style ppmm33dd, e.g.:
              set style data pm3d

        Note that when plotting several plots, they are plotted in the
        order given on the command line. This can be of interest espe-
        cially for filled surfaces which can overwrite and therefore
        hide part of earlier plots.

        If wwiitthh ppmm33dd is specified in the sspplloott command line, then it
        accepts the 'at' option.  The following plots draw three color










   GNUPLOT 4.0                                                      117


        surfaces at different altitudes:
              set border 4095
              set pm3d at s
              splot 10*x with pm3d at b, x*x-y*y, x*x+y*y with pm3d at
        t

        See also help for sseett ppaalleettttee, sseett ccbbrraannggee, sseett ccoolloorrbbooxx, xx1111
        ppmm33dd and definitely the demo file ddeemmoo//ppmm33dd..ddeemm.




        3388..4499..  PPaalleettttee


        Palette is a color storage for use by ppmm33dd, filled color con-
        tours or polygons, color histograms, color gradient background,
        and whatever it is or it will be implemented...  Here it stands
        for a palette of smooth "continuous" colors or grays, but let's
        call it just a palette.

        Color palettes require terminal entries for filled color poly-
        gons and palettes of smooth colors, are currently available for
        terminals listed in help for sseett ppmm33dd. The range of color val-
        ues are adjustable independently by sseett ccbbrraannggee and sseett lloogg ccbb.
        The whole color palette is visualized in the ccoolloorrbbooxx.

        Syntax:
              set palette
              set palette {
                         { gray | color }
                         { gamma <gamma> }
                         {   rgbformulae <r>,<g>,<b>
                           | defined { ( <gray1> <color1> {, <grayN>
        <colorN>}... ) }
                           | file '<filename>' {datafile-modifiers}
                           | functions <R>,<G>,<B>
                         }
                         { model { RGB | HSV | CMY | YIQ | XYZ } }
                         { positive | negative }
                         { nops_allcF | ps_allcF }
                         { maxcolors <maxcolors> }
                       }
              show palette
              show palette palette <n> {{float | int}}
              show palette gradient
              show palette fit2rgbformulae
              show palette rgbformulae
              show palette colornames

        sseett ppaalleettttee (i.e. without options) sets up the default values.
        Otherwise, the options can be given in any order.  sshhooww ppaalleettttee
        shows the current palette properties.










   GNUPLOT 4.0                                                      118


        sshhooww ppaalleettttee ggrraaddiieenntt displays the gradient defining the
        palette (if appropriate).  sshhooww ppaalleettttee rrggbbffoorrmmuullaaee prints the
        available fixed gray --> color transformation formulae.  sshhooww
        ppaalleettttee ccoolloorrnnaammeess prints the implemented color names.

        sshhooww ppaalleettttee ppaalleettttee <<nn>> prints to screen or to the file given
        by sseett oouuttppuutt table of RGB triplets calculated for the current
        palette settings and a palette having <n> discrete colors.  The
        default wide table can be limited to 3 columns of r,g,b float
        values [0..1] or integer values [0..255] by options float or
        int, respectively.  This way, the current gnuplot color palette
        can be loaded into other imaging applications, for example
        Octave.  Additionally to this textual list of RGB table, you
        can enjoy command tteesstt ppaalleettttee to draw graphically the R,G,B
        profiles for the current palette.

        The following options determine the coloring properties.

        Figure using this palette can be ggrraayy or ccoolloorr.  For instance,
        in ppmm33dd color surfaces the gray of each small spot is obtained
        by mapping the averaged z-coordinate of the 4 corners of sur-
        face quadrangles into the range [min_z,max_z] providing range
        of grays [0:1]. This value can be used directly as the gray for
        gray maps. The color map requires a transformation gray -->
        (R,G,B), i.e. a mapping [0:1] --> ([0:1],[0:1],[0:1]).

        Basically two different types of mappings can be used:  Ana-
        lytic formulae to convert gray to color, or discrete mapping
        tables which are interpolated.  rrggbbffoorrmmuullaaee and ffuunnccttiioonnss use
        analytic formulae whereas ddeeffiinneedd and ffiillee use interpolated
        tables.  rrggbbffoorrmmuullaaee reduces the size of postscript output to a
        minimum.

        The command sshhooww ppaalleettttee ffiitt22rrggbbffoorrmmuullaaee finds the best match-
        ing sseett ppaalleettttee rrggbbffoorrmmuullaaee for the current sseett ppaalleettttee. Natu-
        rally, it makes sense to use it for non-rgbformulae palettes.
        This command can be found useful mainly for external programs
        using the same rgbformulae definition of palettes as gnuplot,
        like zimg.

        sseett ppaalleettttee ggrraayy switches to a gray only palette.  rrggbbffoorrmmuullaaee,
        ddeeffiinneedd, ffiillee and ffuunnccttiioonnss switch to a color mapping.  sseett
        ppaalleettttee ccoolloorr is an easy way to switch back from the gray
        palette to the last color mapping.

        Automatic gamma correction via sseett ppaalleettttee ggaammmmaa <<ggaammmmaa>> can be
        done for gray maps only (sseett ppaalleettttee ggrraayy).  Linear mapping to
        gray is for gamma equals 1, see tteesstt ppaalleettttee.  Gamma is ignored
        for color mappings.

        Most terminals support only discrete number of colors (e.g. 256
        colors in gif).  All entries of the palette remaining after the
        default gnuplot linetype colors declaration are allocated for










   GNUPLOT 4.0                                                      119


        pm3d by default.  Then mmuullttiipplloott could fail if there are no
        more color positions in the terminal available.  Then you
        should use sseett ppaalleettttee mmaaxxccoolloorrss <<mmaaxxccoolloorrss>> with a reasonably
        small value.  This option can also be used to separate levels
        of z=constant in discrete steps, thus to emulate filled con-
        tours. Default value of 0 stays for allocating all remaining
        entries in the terminal palette or for to use exact mapping to
        RGB.

        RGB color space might not be the most useful color space to
        work in.  For that reason you may change the color space with
        mmooddeell to one of RRGGBB, HHSSVV, CCMMYY, YYIIQQ and XXYYZZ.  Using color names
        for ddeeffiinneedd tables and a color space other than RGB will result
        in funny colors.  All explanation have been written for RGB
        color space, so please note, that RR can be HH, CC, YY, or XX,
        depending on the actual color space (GG and BB accordingly).

        All values for all color spaces are limited to [0,1].

        RGB stands for Red, Green and Blue;  CMY stands for Cyan,
        Magenta and Yellow; HSV stands for Hue, Saturation, and Value;
        YIQ is the color model used by the U.S. Commercial Color Tele-
        vision Broadcasting, it is basically an RGB recoding with down-
        ward compatibility for black and white television; XYZ are the
        three primary colors of the color model defined by the 'Commis-
        sion Internationale de l'Eclairage' (CIE).  For more informa-
        tion on color models see:
                  http://www.cs.rit.edu/~ncs/color/glossary.htm
        and
                  http://cs.fit.edu/wds/classes/cse5255/cse5255/davis/index.html





             3388..4499..11..  RRggbbffoorrmmuullaaee


             For rrggbbffoorrmmuullaaee three suitable mapping functions have to
             be chosen.  This is done via rrggbbffoorrmmuullaaee <<rr>>,,<<gg>>,,<<bb>>.  The
             available mapping functions are listed by sshhooww ppaalleettttee
             rrggbbffoorrmmuullaaee.  Default is 77,,55,,1155, some other examples are
             33,,1111,,66, 2211,,2233,,33 or 33,,2233,,2211.  Negative numbers, like
             33,,--1111,,--66, mean inverted color (i.e.  1-gray passed into
             the formula, see also ppoossiittiivvee and nneeggaattiivvee options
             below).

             Some nice schemes in RGB color space
                7,5,15   ... traditional pm3d (black-blue-red-yellow)
                3,11,6   ... green-red-violet
                23,28,3  ... ocean (green-blue-white); try also all
             other permutations
                21,22,23 ... hot (black-red-yellow-white)










   GNUPLOT 4.0                                                      120


                30,31,32 ... color printable on gray (black-blue-vio-
             let-yellow-white)
                33,13,10 ... rainbow (blue-green-yellow-red)
                34,35,36 ... AFM hot (black-red-yellow-white)

             A full color palette in HSV color space
                3,2,2    ... red-yellow-green-cyan-blue-magenta-red

             Please note that even if called rrggbbffoorrmmuullaaee the formulas
             might actually determine the <H>,<S>,<V> or <X>,<Y>,<Z> or
             ... color components as usual.

             Use ppoossiittiivvee and nneeggaattiivvee to invert the figure colors.

             Note that it is possible to find a set of the best match-
             ing rgbformulae for any other color scheme by the command
                show palette fit2rgbformulae



             3388..4499..22..  DDeeffiinneedd


             Gray-to-rgb mapping can be manually set by use of ddeeffiinneedd:
             A color gradient is defined and used to give the rgb val-
             ues.  Such a  gradient is a piecewise linear mapping from
             gray values in [0,1] to the RGB space [0,1]x[0,1]x[0,1].
             You have to specify the gray values and the corresponding
             RGB values in between a linear interpolation shall take
             place:

             Syntax:
                   set palette  defined { ( <gray1> <color1> {, <grayN>
             <colorN>}... ) }

             <grayX> are gray values which are mapped to [0,1] and
             <colorX> are the corresponding rgb colors.  The color can
             be specified in three different ways:

                  <color> :=  { <r> <g> <b> | '<color-name>' |
             '#rrggbb' }

             Either by three numbers (each in [0,1]) for red, green and
             blue, separated by whitespace, or the name of the color in
             quotes or X style color specifiers also in quotes.  You
             may freely mix the three types in a gradient definition,
             but the named color "red" will be something strange if RGB
             is not selected as color space.  Use sshhooww ppaalleettttee ccoolloorr--
             nnaammeess for a list of known color names.

             Please note, that even if written as <r>, this might actu-
             ally be the <H> component in HSV color space or <X> in
             CIE-XYZ space, or ...  depending on the selected color










   GNUPLOT 4.0                                                      121


             model.

             The <gray> values have to form an ascending sequence of
             real numbers; the sequence will be automatically rescaled
             to [0,1].

             sseett ppaalleettttee ddeeffiinneedd (without a gradient definition in
             braces) switches to RGB color space and uses a preset
             full-spectrum color gradient.  Use sshhooww ppaalleettttee ggrraaddiieenntt
             to display the gradient.

             Examples:

             To produce a gray palette (useless but instructive) use:
                  set palette model RGB
                  set palette defined ( 0 "black", 1 "white" )

             To produce a blue yellow red palette use (all equivalent):
                   set palette defined ( 0 "blue", 1 "yellow", 2 "red"
             )
                   set palette defined ( 0 0 0 1, 1 1 1 0, 2 1 0 0 )
                   set palette defined ( 0 "#0000ff", 1 "#ffff00", 2
             "ff0000" )

             To produce some rainbow-like palette use:
                   set palette defined ( 0 "blue", 3 "green", 6 "yel-
             low", 10 "red" )

             Full color spectrum within HSV color space:
                   set palette model HSV
                   set palette defined ( 0 0 1 1, 1 1 1 1 )
                   set palette defined ( 0 0 1 0, 1 0 1 1, 6 0.8333 1
             1, 7 0.8333 0 1)

             To produce a palette with few colors only use:
                   set palette model RGB maxcolors 4
                   set palette defined ( 0 "blue", 1 "green", 2 "yel-
             low", 3 "red" )

             'Traffic light' palette (non-smooth color jumps at gray =
             1/3 and 2/3).
                   set palette model RGB
                   set palette defined (0 "dark-green", 1 "green", 1
             "yellow", \
                                        2 "dark-yellow", 2 "red", 3
             "dark-red" )

















   GNUPLOT 4.0                                                      122


             3388..4499..33..  FFuunnccttiioonnss


             Use sseett ppaalleettttee ffuunnccttiioonnss <<RReexxpprr>>,, <<GGeexxpprr>>,, <<BBeexxpprr>> to
             define three formulae for the R(gray), G(gray) and B(gray)
             mapping.  The three formulae may depend on the variable
             ggrraayy which will take values in [0,1] and should also pro-
             duce values in [0,1].  Please note that <Rexpr> might be a
             formula for the H-value if HSV color space has been chosen
             (same for all other formulae and color spaces).

             Examples:

             To produce a full color palette use:
                   set palette model HSV functions gray, 1, 1

             A nice black to gold palette:
                   set palette model XYZ functions gray**0.35,
             gray**0.5, gray**0.8

             A gamma-corrected black and white palette
                   gamma = 2.2
                   color(gray) = gray**(1./gamma)
                   set palette model RGB functions color(gray),
             color(gray), color(gray)




             3388..4499..44..  FFiillee


             sseett ppaalleettttee ffiillee is basically a sseett ppaalleettttee ddeeffiinneedd ((<<ggrraa--
             ddiieenntt>>)) where <gradient> is read from a datafile.  Either
             4 columns (gray,R,G,B) or just three columns (R,G,B) have
             to be selected via the uussiinngg data file modifier.  In the
             three column case, the line number will be used as gray.
             The gray range is automatically rescaled to [0,1].  The
             file is read as a normal data file, so all datafile modi-
             fiers can be used.  Please note, that RR might actually be
             e.g. HH if HSV color space is selected.

             As usual <filename> may be ''--'' which means that the data
             follow the command inline and are terminated by a single ee
             on a line of its own.

             Use sshhooww ppaalleettttee ggrraaddiieenntt to display the gradient.

             Examples:

             Read in a palette of RGB triples each in range [0,255]:
                   set palette file 'some-palette' using
             ($1/255):($2/255):($3/255)










   GNUPLOT 4.0                                                      123


             Equidistant rainbow (blue-green-yellow-red) palette:
                   set palette model RGB file "-"
                   0 0 1
                   0 1 0
                   1 1 0
                   1 0 0
                   e




             3388..4499..55..  GGaammmmaa--ccoorrrreeccttiioonn


             For gray mappings gamma correction can be turned on by sseett
             ppaalleettttee ggaammmmaa <<ggaammmmaa>>.  <gamma> defaults to 1.5 which is
             quite suitable for most terminals.

             For color mappings no automatic gamma correction is done
             by gnuplot.  But you may easily implement gamma correc-
             tion, here an example for a gray scale image by use of
             explicit functions for the red, green and blue component
             with slightly different values of gamma

             Example:
                   set palette model RGB
                   set palette functions gray**0.64, gray**0.67,
             gray**0.70

             To use gamma correction with interpolated gradients spec-
             ify intermediate gray values with appropriate colors.
             Instead of

                   set palette defined ( 0 0 0 0, 1 1 1 1 )

             use e.g.

                  set palette defined ( 0 0 0 0, 0.5 .73 .73 .73, 1 1 1
             1 )

             or even more intermediate points until the linear interpo-
             lation fits the "gamma corrected" interpolation well
             enough.




             3388..4499..66..  PPoossttssccrriipptt


             In order to reduce the size of postscript files, the gray
             value and not all three calculated r,g,b values are writ-
             ten to the file.  Therefore the analytical formulae are










   GNUPLOT 4.0                                                      124


             coded directly in the postscript language as a header just
             before the pm3d drawing, see /g and /cF definitions.  Usu-
             ally, it makes sense to write therein definitions of only
             the 3 formulae used.  But for multiplot or any other rea-
             son you may want to manually edit the transformations
             directly in the postscript file.  This is the default
             option nnooppss__aallllccFF.  Using the option ppss__aallllccFF writes post-
             script definitions of all formulae.  This you may find
             interesting if you want to edit the postscript file in
             order to have different palettes for different surfaces in
             one graph.  Well, you can achieve this functionality by
             mmuullttiipplloott with fixed oorriiggiinn and ssiizzee.

             If pm3d map has been plotted from gridded or almost regu-
             lar data with an output to a postscript file, then it is
             possible to reduce the size of this postscript file up to
             at about 50% by the enclosed awk script ppmm33ddCCoommpprreessss..aawwkk.
             This you may find  interesting if you intend to keep the
             file for including it into your publication or before
             downloading a very large file into a slow printer. Usage:
                 awk -f pm3dCompress.awk thefile.ps >smallerfile.ps

             If pm3d map has been plotted from rectangular gridded data
             with an output to a postscript file, then it is possible
             to reduce the file size even more by the enclosed awk
             script ppmm33ddCCoonnvveerrttTTooIImmaaggee..aawwkk.  Usage:
                 awk -f pm3dConvertToImage.awk <thefile.ps >smaller-
             file.ps

             You may manually change the postscript output from gray to
             color and vice versa and change the definition of <maxcol-
             ors>.




        3388..5500..  PPooiinnttssiizzee


        The sseett ppooiinnttssiizzee command scales the size of the points used in
        plots.

        Syntax:
              set pointsize <multiplier>
              show pointsize

        The default is a multiplier of 1.0.  Larger pointsizes may be
        useful to make points more visible in bitmapped graphics.

        The pointsize of a single plot may be changed on the pplloott com-
        mand.  See pplloott wwiitthh for details.

        Please note that the pointsize setting is not supported by all










   GNUPLOT 4.0                                                      125


        terminal types.



        3388..5511..  PPoollaarr


        The sseett ppoollaarr command changes the meaning of the plot from
        rectangular coordinates to polar coordinates.

        Syntax:
              set polar
              unset polar
              show polar

        There have been changes made to polar mode in version 3.7, so
        that scripts for ggnnuupplloott versions 3.5 and earlier will require
        modification.  The main change is that the dummy variable t is
        used for the angle so that the x and y ranges can be controlled
        independently.  Other changes are: 1) tics are no longer put
        along the zero axes automatically ---use sseett xxttiiccss aaxxiiss nnoommiirr--
        rroorr; sseett yyttiiccss aaxxiiss nnoommiirrrroorr; 2) the grid, if selected, is not
        automatically polar ---use sseett ggrriidd ppoollaarr; 3) the grid is not
        labelled with angles ---use sseett llaabbeell as necessary.

        In polar coordinates, the dummy variable (t) is an angle.  The
        default range of t is [0:2*pi], or, if degree units have been
        selected, to [0:360] (see sseett aanngglleess).

        The command uunnsseett ppoollaarr changes the meaning of the plot back to
        the default rectangular coordinate system.

        The sseett ppoollaarr command is not supported for ssppllootts.  See the sseett
        mmaappppiinngg command for similar functionality for ssppllootts.

        While in polar coordinates the meaning of an expression in t is
        really r = f(t), where t is an angle of rotation.  The trange
        controls the domain (the angle) of the function, and the x and
        y ranges control the range of the graph in the x and y direc-
        tions.  Each of these ranges, as well as the rrange, may be
        autoscaled or set explicitly.  See sseett xxrraannggee for details of
        all the rraannggeess commands.

        Example:
              set polar
              plot t*sin(t)
              plot [-2*pi:2*pi] [-3:3] [-3:3] t*sin(t)

        The first pplloott uses the default polar angular domain of 0 to
        2*pi.  The radius and the size of the graph are scaled automat-
        ically.  The second pplloott expands the domain, and restricts the
        size of the graph to [-3:3] in both directions.











   GNUPLOT 4.0                                                      126


        You may want to sseett ssiizzee ssqquuaarree to have ggnnuupplloott try to make the
        aspect ratio equal to unity, so that circles look circular.
        See also polar demos (polar.dem) and polar data plot (pol-
        dat.dem).



        3388..5522..  PPrriinntt


        The sseett pprriinntt command redirects the output of the pprriinntt command
        to a file.

        Syntax:
              set print
              set print "-"
              set print "<filename>"
              set print "<filename>" append
              set print "|<shell_command>"

        Without "<filename>", the output file is restored to <STDERR>.
        The <filename> "-" means <STDOUT>. The aappppeenndd flag causes the
        file to be opened in append mode.  A <filename> starting with
        "|" is opened as a pipe to the <shell_command> on platforms
        that support piping.



        3388..5533..  RRmmaarrggiinn


        The command sseett rrmmaarrggiinn sets the size of the right margin.
        Please see sseett mmaarrggiinn for details.



        3388..5544..  RRrraannggee


        The sseett rrrraannggee command sets the range of the radial coordinate
        for a graph in polar mode.  Please see sseett xxrraannggee for details.



        3388..5555..  SSaammpplleess


        The sampling rate of functions, or for interpolating data, may
        be changed by the sseett ssaammpplleess command.

        Syntax:
              set samples <samples_1> {,<samples_2>}
              show samples










   GNUPLOT 4.0                                                      127


        By default, sampling is set to 100 points.  A higher sampling
        rate will produce more accurate plots, but will take longer.
        This parameter has no effect on data file plotting unless one
        of the interpolation/approximation options is used.  See pplloott
        ssmmooootthh re 2-d data and sseett ccnnttrrppaarraamm and sseett ddggrriidd33dd re 3-d
        data.

        When a 2-d graph is being done, only the value of <samples_1>
        is relevant.

        When a surface plot is being done without the removal of hidden
        lines, the value of samples specifies the number of samples
        that are to be evaluated for the isolines.  Each iso-v line
        will have <sample_1> samples and each iso-u line will have
        <sample_2> samples.  If you only specify <samples_1>, <sam-
        ples_2> will be set to the same value as <samples_1>.  See also
        sseett iissoossaammpplleess.



        3388..5566..  SSiizzee


        The sseett ssiizzee command scales the displayed size of the plot.

        Syntax:
              set size {{no}square | ratio <r> | noratio}
        {<xscale>,<yscale>}
              show size

        The <xscale> and <yscale> values are the scaling factors for
        the size of the plot, which includes the graph and the margins.

        rraattiioo causes ggnnuupplloott to try to create a graph with an aspect
        ratio of <r> (the ratio of the y-axis length to the x-axis
        length) within the portion of the plot specified by <xscale>
        and <yscale>.

        The meaning of a negative value for <r> is different.  If
        <r>=-1, gnuplot tries to set the scales so that the unit has
        the same length on both the x and y axes (suitable for geo-
        graphical data, for instance).  If <r>=-2, the unit on y has
        twice the length of the unit on x, and so on.

        The success of ggnnuupplloott in producing the requested aspect ratio
        depends on the terminal selected.  The graph area will be the
        largest rectangle of aspect ratio <r> that will fit into the
        specified portion of the output (leaving adequate margins, of
        course).

        ssqquuaarree is a synonym for rraattiioo 11.

        Both nnoorraattiioo and nnoossqquuaarree return the graph to the default










   GNUPLOT 4.0                                                      128


        aspect ratio of the terminal, but do not return <xscale> or
        <yscale> to their default values (1.0).

        rraattiioo and ssqquuaarree have no effect on 3-d plots.

        sseett ssiizzee is relative to the default size, which differs from
        terminal to terminal.  Since ggnnuupplloott fills as much of the
        available plotting area as possible by default, it is safer to
        use sseett ssiizzee to decrease the size of a plot than to increase
        it.  See sseett tteerrmmiinnaall for the default sizes.

        On some terminals, changing the size of the plot will result in
        text being misplaced.

        Examples:

        To set the size to normal size use:
              set size 1,1

        To make the graph half size and square use:
              set size square 0.5,0.5

        To make the graph twice as high as wide use:
              set size ratio 2

        See also
         airfoil demo.



        3388..5577..  SSttyyllee


        Default plotting styles are chosen with the sseett ssttyyllee ddaattaa and
        sseett ssttyyllee ffuunnccttiioonn commands.  See pplloott wwiitthh for information
        about how to override the default plotting style for individual
        functions and data sets.  See pplloottttiinngg ssttyylleess for a complete
        list of styles.

        Syntax:
              set style function <style>
              set style data <style>
              show style function
              show style data

        Default styles for specific plotting elements may also be set.

        Syntax:
              set style arrow <n> <arrowstyle>
              set style fill <fillstyle>
              set style line <n> <linestyle>












   GNUPLOT 4.0                                                      129


             3388..5577..11..  SSeett ssttyyllee aarrrrooww


             Each terminal has a default set of arrow and point types,
             which can be seen by using the command tteesstt.  sseett ssttyyllee
             aarrrrooww defines a set of arrow types and widths and point
             types and sizes so that you can refer to them later by an
             index instead of repeating all the information at each
             invocation.

             Syntax:
                   set style arrow <index> {nohead | head | heads}
                                           {size
             <length>,<angle>{,<backangle>}}
                                           {filled | empty | nofilled}
                                           {front | back}
                                           { {linestyle | ls
             <line_style>}
                                             | {linetype | lt
             <line_type>}
                                               {linewidth | lw
             <line_width} }
                   unset style arrow
                   show style arrow

             <index> is an integer that identifies the arrowstyle.

             Specifying nnoohheeaadd produces arrows drawn without a head---a
             line segment.  This gives you yet another way to draw a
             line segment on the plot.  By default, arrows have one
             head. Specifying hheeaaddss draws arrow heads on both ends of
             the line.

             Head size can be controlled by ssiizzee <<lleennggtthh>>,,<<aannggllee>> or
             ssiizzee <<lleennggtthh>>,,<<aannggllee>>,,<<bbaacckkaannggllee>> where <<lleennggtthh>> defines
             length of each branch of the arrow head and <<aannggllee>> the
             angle (in degrees) they make with the arrow. <<LLeennggtthh>> is
             in x-axis units; this can be changed by ffiirrsstt, sseeccoonndd,
             ggrraapphh or ssccrreeeenn before the <<lleennggtthh>>; see ccoooorrddiinnaatteess for
             details.  <<BBaacckkaannggllee>> only takes effect when ffiilllleedd or
             eemmppttyy is also used. Then, <<bbaacckkaannggllee>> is the angle (in
             degrees) the back branches make with the arrow (in the
             same direction as <<aannggllee>>).  The ffiigg terminal has a
             restricted backangle function. It supports three different
             angles. There are two thresholds: Below 70 degrees, the
             arrow head gets an indented back angle. Above 110 degrees,
             the arrow head has an acute back angle. Between these
             thresholds, the back line is straight.

             Specifying ffiilllleedd produces filled arrow heads (if heads
             are used).  Filling is supported on filled-polygon capable
             terminals, see help of ppmm33dd for their list, otherwise the
             arrow heads are closed but not filled.  The same result










   GNUPLOT 4.0                                                      130


             (closed but not filled arrow head) is reached by specify-
             ing eemmppttyy.  Further, filling and outline is obviously not
             supported on terminals drawing arrows by their own spe-
             cific routines, like mmeettaaffoonntt, mmeettaappoosstt, llaatteexx or ttggiiff.

             The line style may be selected from a user-defined list of
             line styles (see sseett ssttyyllee lliinnee) or may be defined here by
             providing values for <<lliinnee__ttyyppee>> (an index from the
             default list of styles) and/or <<lliinnee__wwiiddtthh>> (which is a
             multiplier for the default width).

             Note, however, that if a user-defined line style has been
             selected, its properties (type and width) cannot be
             altered merely by issuing another sseett ssttyyllee aarrrrooww command
             with the appropriate index and lltt or llww.

             If ffrroonntt is given, the arrows are written on top of the
             graphed data. If bbaacckk is given (the default), the arrow is
             written underneath the graphed data.  Using ffrroonntt will
             prevent a arrow from being obscured by dense data.

             Examples:

             To draw an arrow without an arrow head and double width,
             use:
                   set style arrow 1 nohead lw 2
                   set arrow arrowstyle 1

              See also `set arrow` for further examples.




             3388..5577..22..  SSeett ssttyyllee ddaattaa


             The sseett ssttyyllee ddaattaa command changes the default plotting
             style for data plots.

             Syntax:
                   set style data <plotting-style>
                   show style data

             See pplloottttiinngg ssttyylleess for the choices.  If no choice is
             given, the choices are listed.  sshhooww ssttyyllee ddaattaa shows the
             current default data plotting style.



             3388..5577..33..  SSeett ssttyyllee ffiillll













   GNUPLOT 4.0                                                      131


             The sseett ssttyyllee ffiillll command is used to set the style of
             boxes or candlesticks.

             Syntax:
                   set style fill {empty | solid {<density>} | pattern
             {<n>}}
                                  {border {<linetype>} | noborder}

             The default fillstyle is eemmppttyy.

             The ssoolliidd option causes filling with a solid color, if the
             terminal supports that. The <density> parameter specifies
             the intensity of the fill color. At a <density> of 0.0,
             the box is empty, at <density> of 1.0, the inner area is
             of the same color as the current linetype.  Some terminal
             types can vary the density continuously; others implement
             only a few levels of partial fill.  If no <density> param-
             eter is given, it defaults to 1.

             The ppaatttteerrnn option causes filling to be done with a fill
             pattern supplied by the terminal driver.  The kind and
             number of available fill patterns depend on the terminal
             driver.  If multiple datasets using filled boxes are plot-
             ted, the pattern cycles through all available pattern
             types, starting from pattern <n>, much as the line type
             cycles for multiple line plots.

             The eemmppttyy option causes filled boxes not to be filled.
             This is the default.  It is equivalent to the ssoolliidd option
             with a <density> parameter of zero.

             By default, bboorrddeerr, the box is bounded by a solid line of
             the current linetype. bboorrddeerr <<lltt>> specifies that a border
             is to be drawn using linetype <lt>. nnoobboorrddeerr specifies
             that no bounding lines are drawn.



             3388..5577..44..  SSeett ssttyyllee ffuunnccttiioonn


             The sseett ssttyyllee ffuunnccttiioonn command changes the default plot-
             ting style for function plots.

             Syntax:
                   set style function <plotting-style>
                   show style function

             See pplloottttiinngg ssttyylleess for the choices.  If no choice is
             given, the choices are listed.  sshhooww ssttyyllee ffuunnccttiioonn shows
             the current default function plotting style.












   GNUPLOT 4.0                                                      132


             3388..5577..55..  SSeett ssttyyllee lliinnee


             Each terminal has a default set of line and point types,
             which can be seen by using the command tteesstt.  sseett ssttyyllee
             lliinnee defines a set of line types and widths and point
             types and sizes so that you can refer to them later by an
             index instead of repeating all the information at each
             invocation.

             Syntax:
                   set style line <index> {linetype  | lt <line_type>}
                                          {linewidth | lw <line_width>}
                                          {pointtype | pt <point_type>}
                                          {pointsize | ps <point_size>}
                                          {palette}
                   unset style line
                   show style line

             The line and point types are taken from the default types
             for the terminal currently in use.  The line width and
             point size are multipliers for the default width and size
             (but note that <point_size> here is unaffected by the mul-
             tiplier given on sseett ppooiinnttssiizzee).

             The defaults for the line and point types is the index.
             The defaults for the width and size are both unity.

             Linestyles created by this mechanism do not replace the
             default styles; both may be used.

             Not all terminals support the lliinneewwiiddtthh and ppooiinnttssiizzee fea-
             tures; if not supported, the option will be ignored.

             Note that this feature is not completely implemented;
             linestyles defined by this mechanism may be used with
             pplloott, sspplloott, rreepplloott, and sseett aarrrrooww, but not by other com-
             mands that allow the default index to be used, such as sseett
             ggrriidd.

             If gnuplot was built with pm3d support, the special key-
             word ppaalleettttee is allowed as lliinneettyyppee for splots (the 2d
             pplloott command ignores ppaalleettttee).  In this case the line
             color is chosen from a smooth palette which was set previ-
             ously with the command sseett ppaalleettttee.  The color value cor-
             responds to the z-value (elevation) of the splot.

             Example: Suppose that the default lines for indices 1, 2,
             and 3 are red, green, and blue, respectively, and the
             default point shapes for the same indices are a square, a
             cross, and a triangle, respectively.  Then

                   set style line 1 lt 2 lw 2 pt 3 ps 0.5










   GNUPLOT 4.0                                                      133


             defines a new linestyle that is green and twice the
             default width and a new pointstyle that is a half-sized
             triangle.  The commands

                   set style function lines
                   plot f(x) lt 3, g(x) ls 1

             will create a plot of f(x) using the default blue line and
             a plot of g(x) using the user-defined wide green line.
             Similarly the commands

                   set style function linespoints
                   plot p(x) lt 1 pt 3, q(x) ls 1

             will create a plot of p(x) using the default triangles
             connected by a red line and q(x) using small triangles
             connected by a green line.

                   splot sin(sqrt(x*x+y*y))/sqrt(x*x+y*y) w l pal

             creates a surface plot using smooth colors according to
             ppaalleettttee. Note, that this works only on some terminals.

             See also sseett ppaalleettttee, sseett ppmm33dd.




             3388..5577..66..  PPlloottttiinngg ssttyylleess



             The commands sseett ssttyyllee ddaattaa and sseett ssttyyllee ffuunnccttiioonn change
             the default plotting style for subsequent pplloott and sspplloott
             commands.

             The types used for all line and point styles (i.e., solid,
             dash-dot, color, etc. for lines; circles, squares,
             crosses, etc. for points) will be either those specified
             on the pplloott or sspplloott command or will be chosen sequen-
             tially from the types available to the terminal in use.
             Use the command tteesstt to see what is available.

             None of the styles requiring more than two columns of
             information (e.g., eerrrroorrbbaarrss or eerrrroorrlliinneess) can be used
             with ssppllootts or function ppllootts. Neither bbooxxeess, ffiilllleeddccuurrvveess
             nor any of the sstteeppss styles can be used with ssppllootts. If an
             inappropriate style is specified, it will be changed to
             ppooiinnttss.

             For 2-d data with more than two columns, ggnnuupplloott is picky
             about the allowed eerrrroorrbbaarrss and eerrrroorrlliinneess styles. The
             uussiinngg option on the pplloott command can be used to set up the










   GNUPLOT 4.0                                                      134


             correct columns for the style you want. (In this discus-
             sion, "column" will be used to refer both to a column in
             the data file and an entry in the uussiinngg list.)

             For three columns, only xxeerrrroorrbbaarrss, yyeerrrroorrbbaarrss (or eerrrroorr--
             bbaarrss), xxeerrrroorrlliinneess, yyeerrrroorrlliinneess (or eerrrroorrlliinneess), bbooxxeess and
             bbooxxeerrrroorrbbaarrss are allowed. If another plot style is used,
             the style will be changed to yyeerrrroorrbbaarrss. The bbooxxeerrrroorrbbaarrss
             style will calculate the boxwidth automatically.

             For four columns, only xxeerrrroorrbbaarrss, yyeerrrroorrbbaarrss (or eerrrroorr--
             bbaarrss), xxyyeerrrroorrbbaarrss, xxeerrrroorrlliinneess, yyeerrrroorrlliinneess (or eerrrroorr--
             lliinneess), xxyyeerrrroorrlliinneess, bbooxxxxyyeerrrroorrbbaarrss, and bbooxxeerrrroorrbbaarrss are
             allowed.  An illegal style will be changed to yyeerrrroorrbbaarrss.

             Five-column data allow only the bbooxxeerrrroorrbbaarrss, ffiinnaanncceebbaarrss,
             and ccaannddlleessttiicckkss styles.  An illegal style will be changed
             to bbooxxeerrrroorrbbaarrss before plotting.

             Six- and seven-column data only allow the xxyyeerrrroorrbbaarrss,
             xxyyeerrrroorrlliinneess, and bbooxxxxyyeerrrroorrbbaarrss styles. Illegal styles
             will be changed to xxyyeerrrroorrbbaarrss before plotting.

             For more information about error bars with and without
             lines, please see pplloott eerrrroorrlliinneess and pplloott eerrrroorrbbaarrss.





                  3388..5577..66..11..  BBooxxeerrrroorrbbaarrss


                  The bbooxxeerrrroorrbbaarrss style is only relevant to 2-d data
                  plotting.  It is a combination of the bbooxxeess and yyeerr--
                  rroorrbbaarrss styles.  The boxwidth will come from the
                  fourth column if the y errors are in the form of
                  "ydelta" and the boxwidth was not previously set
                  equal to -2.0 (sseett bbooxxwwiiddtthh --22..00) or from the fifth
                  column if the y errors are in the form of "ylow
                  yhigh".  The special case  bbooxxwwiiddtthh == --22..00 is for
                  four-column data with y errors in the form "ylow
                  yhigh".  In this case the boxwidth will be calculated
                  so that each box touches the adjacent boxes.  The
                  width will also be calculated in cases where three-
                  column data are used.

                  The box height is determined from the y error in the
                  same way as it is for the yyeerrrroorrbbaarrss style---either
                  from y-ydelta to y+ydelta or from ylow to yhigh,
                  depending on how many data columns are provided.  See
                  also errorbar demo.











   GNUPLOT 4.0                                                      135


                  3388..5577..66..22..  BBooxxeess


                  The bbooxxeess style is only relevant to 2-d plotting.  It
                  draws a box centered about the given x coordinate
                  from the x axis (not the graph border) to the given y
                  coordinate.  The width of the box is obtained in one
                  of three ways.  If it is a data plot and the data
                  file has a third column, this will be used to set the
                  width of the box.  If not, if a width has been set
                  using the sseett bbooxxwwiiddtthh command, this will be used.
                  If neither of these is available, the width of each
                  box will be calculated automatically so that it
                  touches the adjacent boxes.

                  The interior of the boxes is drawn according to the
                  current fillstyle.  See sseett ssttyyllee ffiillll for details.
                  Alternatively a new fillstyle may be specified in the
                  plot command.

                  For fillstyle eemmppttyy the box is filled with the back-
                  ground color.

                  For fillstyle ssoolliidd the box is filled with a solid
                  rectangle of the current drawing color. There is an
                  optional parameter <density> that controls the fill
                  density; it runs from 0 (background color) to 1 (cur-
                  rent drawing color).

                  For fillstyle ppaatttteerrnn the box is filled in the cur-
                  rent drawing color with a pattern, if supported by
                  the terminal driver.

                  Examples:

                  To plot a data file with solid filled boxes with a
                  small vertical space separating them (bargraph):

                        set boxwidth 0.9 relative
                        set style fill solid 1.0
                        plot 'file.dat' with boxes

                  To plot a sine and a cosine curve in pattern-filled
                  boxes style:

                        set style fill pattern
                        plot sin(x) with boxes, cos(x) with boxes

                  The sin plot will use pattern 0; the cos plot will
                  use pattern 1.  Any additional plots would cycle
                  through the patterns supported by the terminal
                  driver.











   GNUPLOT 4.0                                                      136


                  To specify explicit fillstyles for each dataset:

                       plot 'file1' with boxes fs solid 0.25, \
                            'file2' with boxes fs solid 0.50, \
                            'file3' with boxes fs solid 0.75, \
                            'file4' with boxes fill pattern 1, \
                            'file5' with boxes fill empty

                  Currently only the following terminal drivers support
                  fillstyles other than eemmppttyy: x11, windows, pm, post-
                  script, fig, pbm, png, gif, hpdj, hppj, hpljii,
                  hp500c, jpeg, nec_cp6, epson_180dpi, epson_60dpi,
                  epson_lx800, okidata, starc and tandy_60dpi. The BeOS
                  driver (bbee) is untested.



                  3388..5577..66..33..  FFiilllleeddccuurrvveess


                  The ffiilllleeddccuurrvveess style is only relevant to 2-d plot-
                  ting. It draws either the current curve closed and
                  filled, or the region between the current curve and a
                  given axis, horizontal or vertical line, or a point,
                  filled with the current drawing color.

                  Syntax:

                      set style [data | function] filledcurves [option]
                      plot ... with filledcurves [option]

                  where the option can be

                      [closed | {x1 | x2 | y1 | y2}[=<a>] | xy=<x>,<y>]

                  The area is filled between the current curve and
                      filledcurves closed   ... just filled closed
                  curve,
                      filledcurves x1       ... x1 axis,
                      filledcurves x2       ... x2 axis, etc for y1 and
                  y2 axes,
                      filledcurves y1=0     ... line y=0 (at y1 axis)
                  ie parallel to x1 axis,
                      filledcurves y2=42    ... line y=42 (at y2 axis)
                  ie parallel to x2, etc,
                      filledcurves xy=10,20 ... point 10,20 of x1,y1
                  axes (arc-like shape).

                  Note: filling is supported on filled-polygon capable
                  terminals, see help of sseett ppmm33dd for their list.

                  Zoom of a filled curve drawn from a datafile may pro-
                  duce empty or incorrect area because gnuplot is










   GNUPLOT 4.0                                                      137


                  clipping points and lines, and not areas.

                  If the values of <a>, <x>, <y> are out of the drawing
                  boundary, then they are moved to the graph boundary.
                  Then the actually filled area in the case of option
                  xy=<x>,<y> will depend on xrange and yrange.



                  3388..5577..66..44..  BBooxxxxyyeerrrroorrbbaarrss


                  The bbooxxxxyyeerrrroorrbbaarrss style is only relevant to 2-d data
                  plotting.  It is a combination of the bbooxxeess and xxyyeerr--
                  rroorrbbaarrss styles.

                  The box width and height are determined from the x
                  and y errors in the same way as they are for the
                  xxyyeerrrroorrbbaarrss style---either from xlow to xhigh and
                  from ylow to yhigh, or from x-xdelta to x+xdelta and
                  from y-ydelta to y+ydelta , depending on how many
                  data columns are provided.

                  If filled-box support is present, then the interior
                  of the boxes is drawn according to the current fill-
                  style.  See sseett ssttyyllee ffiillll and bbooxxeess for details.
                  Alternatively a new fillstyle may be specified in the
                  plot command.



                  3388..5577..66..55..  CCaannddlleessttiicckkss


                  The ccaannddlleessttiicckkss style can be used for 2-d data plot-
                  ting of financial data or for generating box-and-
                  whisker plots of statistical data.  Five columns of
                  data are required; in order, these should be the x
                  coordinate (most likely a date) and the opening, low,
                  high, and closing prices.  The symbol is a rectangu-
                  lar box, centered horizontally at the x coordinate
                  and limited vertically by the opening and closing
                  prices.  A vertical line segment at the x coordinate
                  extends up from the top of the rectangle to the high
                  price and another down to the low.  The vertical line
                  will be unchanged if the low and high prices are
                  interchanged.

                  The width of the rectangle can be controlled by the
                  sseett bbooxxwwiiddtthh command.  For backwards compatibility
                  with earlier gnuplot versions, when the boxwidth
                  parameter has not been set then the width of the can-
                  dlestick rectangle is controlled by sseett bbaarrss <<wwiiddtthh>>.










   GNUPLOT 4.0                                                      138


                  By default the rectangle is empty if (open > close),
                  and filled with three vertical bars if (close >
                  open). If filled-boxes support is present, then the
                  rectangle is colored according to sseett ssttyyllee ffiillll
                  <<ffiillllssttyyllee>>.  See sseett bbaarrss and ffiinnaanncceebbaarrss.  See also
                  finance demos.

                  Note: To place additional symbols, such as the median
                  value, on a box-and-whisker plot requires additional
                  plot commands as in this example:

                    # Data columns: X Min 1stQuartile Median 3rdQuar-
                  tile Max
                    set bars 4.0
                    set style fill empty
                    plot 'stat.dat' using 1:3:2:6:5 with candlesticks
                  title 'Quartiles', \
                         ''         using 1:4:4:4:4 with candlesticks
                  lt -1 notitle

                   See `set boxwidth`, `set bars` and `set style fill`.



                  3388..5577..66..66..  DDoottss


                  The ddoottss style plots a tiny dot at each point; this
                  is useful for scatter plots with many points.



                  3388..5577..66..77..  FFiinnaanncceebbaarrss


                  The ffiinnaanncceebbaarrss style is only relevant for 2-d data
                  plotting of financial data.  Five columns of data are
                  required; in order, these should be the x coordinate
                  (most likely a date) and the opening, low, high, and
                  closing prices.  The symbol is a vertical line seg-
                  ment, located horizontally at the x coordinate and
                  limited vertically by the high and low prices.  A
                  horizontal tic on the left marks the opening price
                  and one on the right marks the closing price.  The
                  length of these tics may be changed by sseett bbaarrss.  The
                  symbol will be unchanged if the high and low prices
                  are interchanged.  See sseett bbaarrss and ccaannddlleessttiicckkss, and
                  also the finance demo.















   GNUPLOT 4.0                                                      139


                  3388..5577..66..88..  FFsstteeppss


                  The ffsstteeppss style is only relevant to 2-d plotting.
                  It connects consecutive points with two line seg-
                  ments: the first from (x1,y1) to (x1,y2) and the sec-
                  ond from (x1,y2) to (x2,y2).  See also steps demo.



                  3388..5577..66..99..  HHiisstteeppss


                  The hhiisstteeppss style is only relevant to 2-d plotting.
                  It is intended for plotting histograms.  Y-values are
                  assumed to be centered at the x-values; the point at
                  x1 is represented as a horizontal line from
                  ((x0+x1)/2,y1) to ((x1+x2)/2,y1).  The lines repre-
                  senting the end points are extended so that the step
                  is centered on at x.  Adjacent points are connected
                  by a vertical line at their average x, that is, from
                  ((x1+x2)/2,y1) to ((x1+x2)/2,y2).

                  If aauuttoossccaallee is in effect, it selects the xrange from
                  the data rather than the steps, so the end points
                  will appear only half as wide as the others.  See
                  also steps demo.

                  hhiisstteeppss is only a plotting style; ggnnuupplloott does not
                  have the ability to create bins and determine their
                  population from some data set.



                  3388..5577..66..1100..  IImmppuullsseess


                  The iimmppuullsseess style displays a vertical line from the
                  x axis (not the graph border), or from the grid base
                  for sspplloott, to each point.



                  3388..5577..66..1111..  LLiinneess


                  The lliinneess style connects adjacent points with
                  straight line segments.  See also lliinneettyyppee,
                  lliinneewwiiddtthh, and lliinneessttyyllee.














   GNUPLOT 4.0                                                      140


                  3388..5577..66..1122..  LLiinneessppooiinnttss


                  The lliinneessppooiinnttss style does both lliinneess and ppooiinnttss,
                  that is, it draws a small symbol at each point and
                  then connects adjacent points with straight line seg-
                  ments.  The command sseett ppooiinnttssiizzee may be used to
                  change the size of the points.  See sseett ppooiinnttssiizzee for
                  its usage.

                  lliinneessppooiinnttss may be abbreviated llpp.



                  3388..5577..66..1133..  PPooiinnttss


                  The ppooiinnttss style displays a small symbol at each
                  point.  The command sseett ppooiinnttssiizzee may be used to
                  change the size of the points.  See sseett ppooiinnttssiizzee for
                  its usage.



                  3388..5577..66..1144..  SStteeppss


                  The sstteeppss style is only relevant to 2-d plotting.  It
                  connects consecutive points with two line segments:
                  the first from (x1,y1) to (x2,y1) and the second from
                  (x2,y1) to (x2,y2).  See also steps demo.



                  3388..5577..66..1155..  VVeeccttoorrss


                  The vveeccttoorrss style draws a vector from (x,y) to
                  (x+xdelta,y+ydelta).  Thus it requires four columns
                  of data.  It also draws a small arrowhead at the end
                  of the vector.

                  Example:
                        plot 'file.dat' using 1:2:3:4 with vectors head
                  filled lt 2

                  sseett cclliipp oonnee and sseett cclliipp ttwwoo affect drawing vectors.
                  Please see sseett cclliipp and aarrrroowwssttyyllee.















   GNUPLOT 4.0                                                      141


                  3388..5577..66..1166..  XXeerrrroorrbbaarrss


                  The xxeerrrroorrbbaarrss style is only relevant to 2-d data
                  plots.  xxeerrrroorrbbaarrss is like ddoottss, except that a hori-
                  zontal error bar is also drawn.  At each point (x,y),
                  a line is drawn from (xlow,y) to (xhigh,y) or from
                  (x-xdelta,y) to (x+xdelta,y), depending on how many
                  data columns are provided.  A tic mark is placed at
                  the ends of the error bar (unless sseett bbaarrss is
                  used---see sseett bbaarrss for details).



                  3388..5577..66..1177..  XXyyeerrrroorrbbaarrss


                  The xxyyeerrrroorrbbaarrss style is only relevant to 2-d data
                  plots.  xxyyeerrrroorrbbaarrss is like ddoottss, except that hori-
                  zontal and vertical error bars are also drawn.  At
                  each point (x,y), lines are drawn from (x,y-ydelta)
                  to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y)
                  or from (x,ylow) to (x,yhigh) and from (xlow,y) to
                  (xhigh,y), depending upon the number of data columns
                  provided.  A tic mark is placed at the ends of the
                  error bar (unless sseett bbaarrss is used---see sseett bbaarrss for
                  details).

                  If data are provided in an unsupported mixed form,
                  the uussiinngg filter on the pplloott command should be used
                  to set up the appropriate form.  For example, if the
                  data are of the form (x,y,xdelta,ylow,yhigh), then
                  you can use

                        plot 'data' using 1:2:($1-$3):($1+$3):4:5 with
                  xyerrorbars



                  3388..5577..66..1188..  YYeerrrroorrbbaarrss


                  The yyeerrrroorrbbaarrss (or eerrrroorrbbaarrss) style is only relevant
                  to 2-d data plots.  yyeerrrroorrbbaarrss is like ppooiinnttss, except
                  that a vertical error bar is also drawn.  At each
                  point (x,y), a line is drawn from (x,y-ydelta) to
                  (x,y+ydelta) or from (x,ylow) to (x,yhigh), depending
                  on how many data columns are provided.  A tic mark is
                  placed at the ends of the error bar (unless sseett bbaarrss
                  is used---see sseett bbaarrss for details).  See also error-
                  bar demo.












   GNUPLOT 4.0                                                      142


                  3388..5577..66..1199..  XXeerrrroorrlliinneess


                  The xxeerrrroorrlliinneess style is only relevant to 2-d data
                  plots.  xxeerrrroorrlliinneess is like lliinneessppooiinnttss, except that
                  a horizontal error line is also drawn. At each point
                  (x,y), a line is drawn from (xlow,y) to (xhigh,y) or
                  from (x-xdelta,y) to (x+xdelta,y), depending on how
                  many data columns are provided. A tic mark is placed
                  at the ends of the error bar (unless sseett bbaarrss is
                  used---see sseett bbaarrss for details).



                  3388..5577..66..2200..  XXyyeerrrroorrlliinneess


                  The xxyyeerrrroorrlliinneess style is only relevant to 2-d data
                  plots.  xxyyeerrrroorrlliinneess is like lliinneessppooiinnttss, except that
                  horizontal and vertical error bars are also drawn. At
                  each point (x,y), lines are drawn from (x,y-ydelta)
                  to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y)
                  or from (x,ylow) to (x,yhigh) and from (xlow,y) to
                  (xhigh,y), depending upon the number of data columns
                  provided. A tic mark is placed at the ends of the
                  error bar (unless sseett bbaarrss is used---see sseett bbaarrss for
                  details).

                  If data are provided in an unsupported mixed form,
                  the uussiinngg filter on the pplloott command should be used
                  to set up the appropriate form.  For example, if the
                  data are of the form (x,y,xdelta,ylow,yhigh), then
                  you can use

                        plot 'data' using 1:2:($1-$3):($1+$3):4:5 with
                  xyerrorlines



                  3388..5577..66..2211..  YYeerrrroorrlliinneess


                  The yyeerrrroorrlliinneess (or eerrrroorrlliinneess) style is only rele-
                  vant to 2-d data plots. yyeerrrroorrlliinneess is like lliinneess--
                  ppooiinnttss, except that a vertical error line is also
                  drawn. At each point (x,y), a line is drawn from
                  (x,y-ydelta) to (x,y+ydelta) or from (x,ylow) to
                  (x,yhigh), depending on how many data columns are
                  provided. A tic mark is placed at the ends of the
                  error bar (unless sseett bbaarrss is used---see sseett bbaarrss for
                  details).  See also errorbar demo.












   GNUPLOT 4.0                                                      143


        3388..5588..  SSuurrffaaccee


        The command sseett ssuurrffaaccee controls the display of surfaces by
        sspplloott.

        Syntax:
              set surface
              unset surface
              show surface

        The surface is drawn with the style specified by wwiitthh, or else
        the appropriate style, data or function.

        Whenever uunnsseett ssuurrffaaccee is issued, sspplloott will not draw points or
        lines corresponding to the function or data file points.  Con-
        tours may still be drawn on the surface, depending on the sseett
        ccoonnttoouurr option. uunnsseett ssuurrffaaccee;; sseett ccoonnttoouurr bbaassee is useful for
        displaying contours on the grid base.  See also sseett ccoonnttoouurr.



        3388..5599..  TTeerrmmiinnaall


        ggnnuupplloott supports many different graphics devices.  Use sseett tteerr--
        mmiinnaall to tell ggnnuupplloott what kind of output to generate. Use sseett
        oouuttppuutt to redirect that output to a file or device.

        Syntax:
              set terminal {<terminal-type> | push | pop}
              show terminal

        If <terminal-type> is omitted, ggnnuupplloott will list the available
        terminal types.  <terminal-type> may be abbreviated.

        If both sseett tteerrmmiinnaall and sseett oouuttppuutt are used together, it is
        safest to give sseett tteerrmmiinnaall first, because some terminals set a
        flag which is needed in some operating systems.

        Several terminals have additional options.  For example, see
        dduummbb, iirriiss44dd, hhpplljjiiii or ppoossttssccrriipptt.  The options used by a pre-
        vious invocation sseett tteerrmm <<tteerrmm>> <<ooppttiioonnss>> of a given <<tteerrmm>>
        are remembered, thus subsequent sseett tteerrmm <<tteerrmm>> does not reset
        them.  This helps in printing, for instance, when switching
        among different terminals---previous options don't have to be
        repeated.

        The command sseett tteerrmm ppuusshh remembers the current terminal
        including its settings while sseett tteerrmm ppoopp restores it. This is
        equivalent to ssaavvee tteerrmm and llooaadd tteerrmm, but without accessing
        the filesystem. Therefore they can be used to achieve platform
        independent restoring of the terminal after printing, for










   GNUPLOT 4.0                                                      144


        instance. After gnuplot's startup, the default terminal or that
        from ssttaarrttuupp file is pushed automatically. Therefore portable
        scripts can rely that sseett tteerrmm ppoopp restores the default termi-
        nal on a given platform unless another terminal has been pushed
        explicitly.

        This document may describe drivers that are not available to
        you because they were not installed, or it may not describe all
        the drivers that are available to you, depending on its output
        format.




             3388..5599..11..  AAeedd776677


             The aaeedd551122 and aaeedd776677 terminal drivers support AED graph-
             ics terminals.  The two drivers differ only in their hori-
             zontal ranges, which are 512 and 768 pixels, respectively.
             Their vertical range is 575 pixels.  There are no options
             for these drivers.



             3388..5599..22..  AAiiffmm


             Several options may be set in aaiiffmm---the Adobe Illustrator
             3.0+ driver.

             Syntax:
                   set terminal aifm {<color>} {"<fontname>"} {<font-
             size>}

             <color> is either ccoolloorr or mmoonnoocchhrroommee; "<fontname>" is the
             name of a valid PostScript font; <fontsize> is the size of
             the font in PostScript points, before scaling by the sseett
             ssiizzee command.  Selecting ddeeffaauulltt sets all options to their
             default values: mmoonnoocchhrroommee, "Times-Roman", and 14pt.

             Since AI does not really support multiple pages, multiple
             graphs will be drawn directly on top of one another.  How-
             ever, each graph will be grouped individually, making it
             easy to separate them inside AI (just pick them up and
             move them).

             Examples:
                   set term aifm
                   set term aifm 22
                   set size 0.7,1.4; set term aifm color "Times-Roman"
             14











   GNUPLOT 4.0                                                      145


             3388..5599..33..  AAmmiiggaa


             The aammiiggaa terminal, for Commodore Amiga computers, allows
             the user to plot either to a screen (default), or, if
             Kickstart 3.0 or higher is installed, to a window on the
             current public screen. The font and its size can also be
             selected.

             Syntax:
                   set terminal amiga {screen | window} {"<fontname>"}
             {<fontsize>}

             The default font is 8-point "topaz".

             The screen option uses a virtual screen, so it is possible
             that the graph will be larger than the screen.



             3388..5599..44..  AAppoolllloo


             The aappoolllloo terminal driver supports the Apollo Graphics
             Primitive Resource with rescaling after window resizing.
             It has no options.

             If a fixed-size window is desired, the ggpprr terminal may be
             used instead.



             3388..5599..55..  AAqquuaa


             This terminal relies on AquaTerm.app for display on Mac OS
             X.

             Syntax:
                   set terminal aqua {<n>} {title "<wintitle>"} {size
             <x> <y>}
                                     {fname "<fontface>"} {fsize <font-
             size>}

             where <n> is the number of the window to draw in (default
             is 0), <wintitle> is the name shown in the title bar
             (default "Figure <n>"), <x> <y> is the size of the plot
             (default is 846x594 pt = 11.75x8.25 in).

             Use <fontface> to specify the font to use (default is
             "Times-Roman"), <fontzise> sets the font size (default is
             14.0 pt).











   GNUPLOT 4.0                                                      146


             3388..5599..66..  AAttaarrii SSTT ((vviiaa AAEESS))


             The aattaarrii terminal has options to set the character size
             and the screen colors.

             Syntax:
                   set terminal atari {<fontsize>} {<col0> <col1> ...
             <col15>}

             The character size must appear if any colors are to be
             specified.  Each of the (up to 16) colors is given as a
             three-digit hex number, where the digits represent RED,
             GREEN and BLUE (in that order).  The range of 0--15 is
             scaled to whatever color range the screen actually has.
             On a normal ST screen, odd and even intensities are the
             same.

             Examples:
                   set terminal atari 4    # use small (6x6) font
                   set terminal atari 6 0  # set monochrome screen to
             white on black
                   set terminal atari 13 0 fff f00 f0 f ff f0f
                              # set first seven colors to black, white,
             red, green,
                              # blue, cyan, and purple and use large
             font (8x16).

             Additionally, if an environment variable GNUCOLORS exists,
             its contents are interpreted as an options string, but an
             explicit terminal option takes precedence.



             3388..5599..77..  BBee


             ggnnuupplloott provides the bbee terminal type for use with X
             servers.  This terminal type is set automatically at
             startup if the DDIISSPPLLAAYY environment variable is set, if the
             TTEERRMM environment variable is set to xxtteerrmm, or if the --ddiiss--
             ppllaayy command line option is used.

             Syntax:
                       set terminal be {reset} {<n>}

             Multiple plot windows are supported: sseett tteerrmmiinnaall bbee <<nn>>
             directs the output to plot window number n.  If n>0, the
             terminal number will be appended to the window title and
             the icon will be labeled ggpplltt <<nn>>.  The active window may
             distinguished by a change in cursor (from default to
             crosshair.)











   GNUPLOT 4.0                                                      147


             Plot windows remain open even when the ggnnuupplloott driver is
             changed to a different device.  A plot window can be
             closed by pressing the letter q while that window has
             input focus, or by choosing cclloossee from a window manager
             menu.  All plot windows can be closed by specifying rreesseett,
             which actually terminates the subprocess which maintains
             the windows (unless --ppeerrssiisstt was specified).

             Plot windows will automatically be closed at the end of
             the session unless the --ppeerrssiisstt option was given.

             The size or aspect ratio of a plot may be changed by
             resizing the ggnnuupplloott window.

             Linewidths and pointsizes may be changed from within ggnnuu--
             pplloott with sseett lliinneessttyyllee.

             For terminal type bbee, ggnnuupplloott accepts (when initialized)
             the standard X Toolkit options and resources such as geom-
             etry, font, and name from the command line arguments or a
             configuration file.  See the X(1) man page (or its equiva-
             lent) for a description of such options.

             A number of other ggnnuupplloott options are available for the bbee
             terminal.  These may be specified either as command-line
             options when ggnnuupplloott is invoked or as resources in the
             configuration file ".Xdefaults".  They are set upon ini-
             tialization and cannot be altered during a ggnnuupplloott ses-
             sion.




                  3388..5599..77..11..  CCoommmmaanndd--lliinnee__ooppttiioonnss


                  In addition to the X Toolkit options, the following
                  options may be specified on the command line when
                  starting ggnnuupplloott or as resources in your ".Xdefaults"
                  file:























   GNUPLOT 4.0                                                      148


   +---------------------------------------------------------------------------------+
   |    `-mono`        forces monochrome rendering on color displays.                |
   |    `-gray`        requests grayscale rendering on grayscale or color displays.  |
   |                   (Grayscale displays receive monochrome rendering by default.) |
   |    `-clear`       requests that the window be cleared momentarily before a      |
   |                   new plot is displayed.                                        |
   |    `-raise`       raises plot window after each plot                            |
   |   `-noraise`      does not raise plot window after each plot                    |
   |   `-persist`      plots windows survive after main gnuplot program exits        |
   +---------------------------------------------------------------------------------+


   The options are shown above in their command-line syntax.  When
   entered as resources in ".Xdefaults", they require a different syn-
   tax.

   Example:
             gnuplot*gray: on

   ggnnuupplloott also provides a command line option (--ppooiinnttssiizzee <<vv>>) and a
   resource, ggnnuupplloott**ppooiinnttssiizzee:: <<vv>>, to control the size of points
   plotted with the ppooiinnttss plotting style.  The value vv is a real num-
   ber (greater than 0 and less than or equal to ten) used as a scaling
   factor for point sizes.  For example, --ppooiinnttssiizzee 22 uses points twice
   the default size, and --ppooiinnttssiizzee 00..55 uses points half the normal
   size.



                  3388..5599..77..22..  MMoonnoocchhrroommee__ooppttiioonnss


                  For monochrome displays, ggnnuupplloott does not honor fore-
                  ground or background colors.  The default is black-
                  on-white.  --rrvv or ggnnuupplloott**rreevveerrsseeVViiddeeoo:: oonn requests
                  white-on-black.




                  3388..5599..77..33..  CCoolloorr__rreessoouurrcceess


                  For color displays, ggnnuupplloott honors the following
                  resources (shown here with their default values) or
                  the greyscale resources.  The values may be color
                  names as listed in the BE rgb.txt file on your sys-
                  tem, hexadecimal RGB color specifications (see BE
                  documentation), or a color name followed by a comma
                  and an iinntteennssiittyy value from 0 to 1.  For example,
                  bblluuee,, 00..55 means a half intensity blue.












   GNUPLOT 4.0                                                      149


                    +--------------------------------+
                    |    gnuplot*background: white   |
                    |    gnuplot*textColor: black    |
                    |    gnuplot*borderColor: black  |
                    |    gnuplot*axisColor: black    |
                    |    gnuplot*line1Color: red     |
                    |    gnuplot*line2Color: green   |
                    |    gnuplot*line3Color: blue    |
                    |    gnuplot*line4Color: magenta |
                    |    gnuplot*line5Color: cyan    |
                    |    gnuplot*line6Color: sienna  |
                    |    gnuplot*line7Color: orange  |
                    |    gnuplot*line8Color: coral   |
                    +--------------------------------+



   The command-line syntax for these is, for example,

   Example:
             gnuplot -background coral




                  3388..5599..77..44..  GGrraayyssccaallee__rreessoouurrcceess


                  When --ggrraayy is selected, ggnnuupplloott honors the following
                  resources for grayscale or color displays (shown here
                  with their default values).  Note that the default
                  background is black.



                     +-------------------------------+
                     |    gnuplot*background: black  |
                     |    gnuplot*textGray: white    |
                     |    gnuplot*borderGray: gray50 |
                     |    gnuplot*axisGray: gray50   |
                     |    gnuplot*line1Gray: gray100 |
                     |    gnuplot*line2Gray: gray60  |
                     |    gnuplot*line3Gray: gray80  |
                     |    gnuplot*line4Gray: gray40  |
                     |    gnuplot*line5Gray: gray90  |
                     |    gnuplot*line6Gray: gray50  |
                     |    gnuplot*line7Gray: gray70  |
                     |    gnuplot*line8Gray: gray30  |
                     +-------------------------------+














   GNUPLOT 4.0                                                      150


                  3388..5599..77..55..  LLiinnee__rreessoouurrcceess


                  ggnnuupplloott honors the following resources for setting
                  the width (in pixels) of plot lines (shown here with
                  their default values.)  0 or 1 means a minimal width
                  line of 1 pixel width.  A value of 2 or 3 may improve
                  the appearance of some plots.



                       +---------------------------+
                       |    gnuplot*borderWidth: 2 |
                       |    gnuplot*axisWidth: 0   |
                       |    gnuplot*line1Width: 0  |
                       |    gnuplot*line2Width: 0  |
                       |    gnuplot*line3Width: 0  |
                       |    gnuplot*line4Width: 0  |
                       |    gnuplot*line5Width: 0  |
                       |    gnuplot*line6Width: 0  |
                       |    gnuplot*line7Width: 0  |
                       |    gnuplot*line8Width: 0  |
                       +---------------------------+



   ggnnuupplloott honors the following resources for setting the dash style
   used for plotting lines.  0 means a solid line.  A two-digit number
   jjkk (jj and kk are >= 1  and <= 9) means a dashed line with a repeated
   pattern of jj pixels on followed by kk pixels off.  For example, '16'
   is a "dotted" line with one pixel on followed by six pixels off.
   More elaborate on/off patterns can be specified with a four-digit
   value.  For example, '4441' is four on, four off, four on, one off.
   The default values shown below are for monochrome displays or mono-
   chrome rendering on color or grayscale displays.  For color dis-
   plays, the default for each is 0 (solid line) except for aaxxiissDDaasshheess
   which defaults to a '16' dotted line.



                     +------------------------------+
                     |    gnuplot*borderDashes: 0   |
                     |    gnuplot*axisDashes: 16    |
                     |    gnuplot*line1Dashes: 0    |
                     |    gnuplot*line2Dashes: 42   |
                     |    gnuplot*line3Dashes: 13   |
                     |    gnuplot*line4Dashes: 44   |
                     |    gnuplot*line5Dashes: 15   |
                     |    gnuplot*line6Dashes: 4441 |
                     |    gnuplot*line7Dashes: 42   |
                     |    gnuplot*line8Dashes: 13   |
                     +------------------------------+











   GNUPLOT 4.0                                                      151


             3388..5599..88..  CCggii


             The ccggii and hhccggii terminal drivers support SCO CGI drivers.
             hhccggii is for printers; the environment variable CGIPRNT
             must be set.  ccggii may be used for either a display or
             hardcopy; if the environment variable CGIDISP is set, then
             that display is used.  Otherwise CGIPRNT is used.

             These terminals have no options.



             3388..5599..99..  CCggmm


             The ccggmm terminal generates a Computer Graphics Metafile,
             Version 1.  This file format is a subset of the ANSI
             X3.122-1986 standard entitled "Computer Graphics -
             Metafile for the Storage and Transfer of Picture Descrip-
             tion Information".  Several options may be set in ccggmm.

             Syntax:
                   set terminal cgm {<mode>} {<color>} {<rotation>}
             {solid | dashed}
                                    {width <plot_width>} {linewidth
             <line_width>}
                                    {"<font>"} {<fontsize>}
                                    {<color0> <color1> <color2> ...}

             where <mode> is llaannddssccaappee, ppoorrttrraaiitt, or ddeeffaauulltt; <color>
             is either ccoolloorr or mmoonnoocchhrroommee; <rotation> is either rroottaattee
             or nnoorroottaattee; ssoolliidd draws all curves with solid lines,
             overriding any dashed patterns; <plot_width> is the
             assumed width of the plot in points; <line_width> is the
             line width in points (default 1); <font> is the name of a
             font; and <fontsize> is the size of the font in points
             (default 12).

             By default, ccggmm uses rotated text for the Y axis label.

             The first six options can be in any order.  Selecting
             ddeeffaauulltt sets all options to their default values.

             Each color must be of the form 'xrrggbb', where x is the
             literal character 'x' and 'rrggbb' are the red, green and
             blue components in hex.  For example, 'x00ff00' is green.
             The background color is set first, then the plotting col-
             ors.  Examples:
                   set terminal cgm landscape color rotate dashed width
             432 \
                                  linewidth 1  'Helvetica Bold' 12
             # defaults










   GNUPLOT 4.0                                                      152


                   set terminal cgm linewidth 2  14  # wider lines &
             larger font
                   set terminal cgm portrait "Times Italic" 12
                   set terminal cgm color solid      # no pesky dashes!




                  3388..5599..99..11..  FFoonntt


                  The first part of a Computer Graphics Metafile, the
                  metafile description, includes a font table.  In the
                  picture body, a font is designated by an index into
                  this table.  By default, this terminal generates a
                  table with the following 35 fonts, plus six more with
                  iittaalliicc replaced by oobblliiqquuee, or vice-versa (since at
                  least the Microsoft Office and Corel Draw CGM import
                  filters treat iittaalliicc and oobblliiqquuee as equivalent):












































   GNUPLOT 4.0                                                      153


                   +-----------------------------------+
                   |        CGM fonts                  |
                   +-----------------------------------+
                   |        Helvetica                  |
                   |        Helvetica Bold             |
                   |        Helvetica Oblique          |
                   |        Helvetica Bold Oblique     |
                   |        Times Roman                |
                   |        Times Bold                 |
                   |        Times Italic               |
                   |        Times Bold Italic          |
                   |        Courier                    |
                   |        Courier Bold               |
                   |        Courier Oblique            |
                   |        Courier Bold Oblique       |
                   |        Symbol                     |
                   |        Hershey/Cartographic_Roman |
                   |        Hershey/Cartographic_Greek |
                   |        Hershey/Simplex_Roman      |
                   |        Hershey/Simplex_Greek      |
                   |        Hershey/Simplex_Script     |
                   |        Hershey/Complex_Roman      |
                   |        Hershey/Complex_Greek      |
                   |        Hershey/Complex_Script     |
                   |        Hershey/Complex_Italic     |
                   |        Hershey/Complex_Cyrillic   |
                   |        Hershey/Duplex_Roman       |
                   |        Hershey/Triplex_Roman      |
                   |        Hershey/Triplex_Italic     |
                   |        Hershey/Gothic_German      |
                   |        Hershey/Gothic_English     |
                   |        Hershey/Gothic_Italian     |
                   |        Hershey/Symbol_Set_1       |
                   |        Hershey/Symbol_Set_2       |
                   |        Hershey/Symbol_Math        |
                   |        ZapfDingbats               |
                   |        Script                     |
                   |        15                         |
                   +-----------------------------------+


   The first thirteen of these fonts are required for WebCGM.  The
   Microsoft Office CGM import filter implements the 13 standard fonts
   listed above, and also 'ZapfDingbats' and 'Script'.  However, the
   script font may only be accessed under the name '15'.  For more on
   Microsoft import filter font substitutions, check its help file
   which you may find here:
     C:\Program Files\Microsoft Office\Office\Cgmimp32.hlp
   and/or its configuration file, which you may find here:
     C:\Program Files\Common Files\Microsoft
   Shared\Grphflt\Cgmimp32.cfg

   In the sseett tteerrmm command, you may specify a font name which does not










   GNUPLOT 4.0                                                      154


   appear in the default font table.  In that case, a new font table is
   constructed with the specified font as its first entry. You must
   ensure that the spelling, capitalization, and spacing of the name
   are appropriate for the application that will read the CGM file.
   (Gnuplot and any MIL-D-28003A compliant application ignore case in
   font names.)  If you need to add several new fonts, use several sseett
   tteerrmm commands.

   Example:
         set terminal cgm 'Old English'
         set terminal cgm 'Tengwar'
         set terminal cgm 'Arabic'
         set output 'myfile.cgm'
         plot ...
         set output

   You cannot introduce a new font in a sseett llaabbeell command.2 fontsize
   Fonts are scaled assuming the page is 6 inches wide.  If the ssiizzee
   command is used to change the aspect ratio of the page or the CGM
   file is converted to a different width, the resulting font sizes
   will be scaled up or down accordingly.  To change the assumed width,
   use the wwiiddtthh option.



                  3388..5599..99..22..  LLiinneewwiiddtthh


                  The lliinneewwiiddtthh option sets the width of lines in pt.
                  The default width is 1 pt.  Scaling is affected by
                  the actual width of the page, as discussed under the
                  ffoonnttssiizzee and wwiiddtthh options.



                  3388..5599..99..33..  RRoottaattee


                  The nnoorroottaattee option may be used to disable text rota-
                  tion.  For example, the CGM input filter for Word for
                  Windows 6.0c can accept rotated text, but the DRAW
                  editor within Word cannot.  If you edit a graph (for
                  example, to label a curve), all rotated text is
                  restored to horizontal.  The Y axis label will then
                  extend beyond the clip boundary.  With nnoorroottaattee, the
                  Y axis label starts in a less attractive location,
                  but the page can be edited without damage.  The
                  rroottaattee option confirms the default behavior.















   GNUPLOT 4.0                                                      155


                  3388..5599..99..44..  SSoolliidd


                  The ssoolliidd option may be used to disable dashed line
                  styles in the plots.  This is useful when color is
                  enabled and the dashing of the lines detracts from
                  the appearance of the plot. The ddaasshheedd option con-
                  firms the default behavior, which gives a different
                  dash pattern to each curve.



                  3388..5599..99..55..  SSiizzee


                  Default size of a CGM plot is 32599 units wide and
                  23457 units high for landscape, or 23457 units wide
                  by 32599 units high for portrait.



                  3388..5599..99..66..  WWiiddtthh


                  All distances in the CGM file are in abstract units.
                  The application that reads the file determines the
                  size of the final plot.  By default, the width of the
                  final plot is assumed to be 6 inches (15.24 cm).
                  This distance is used to calculate the correct font
                  size, and may be changed with the wwiiddtthh option.  The
                  keyword should be followed by the width in points.
                  (Here, a point is 1/72 inch, as in PostScript.  This
                  unit is known as a "big point" in TeX.)  Gnuplot
                  eexxpprreessssiioonnss can be used to convert from other units.

                  Example:
                        set terminal cgm width 432            # default
                        set terminal cgm width 6*72           # same as
                  above
                        set terminal cgm width 10/2.54*72     # 10 cm
                  wide



                  3388..5599..99..77..  NNooffoonnttlliisstt


                  The default font table includes the fonts recommended
                  for WebCGM, which are compatible with the Computer
                  Graphics Metafile input filter for Microsoft Office
                  and Corel Draw.  Another application might use dif-
                  ferent fonts and/or different font names, which may
                  not be documented.  As a workaround, the nnooffoonnttlliisstt










   GNUPLOT 4.0                                                      156


                  option deletes the font table from the CGM file.  In
                  this case, the reading application should use a
                  default table.  Gnuplot will still use its own
                  default font table to select font indices.  Thus,
                  'Helvetica' will give you an index of 1, which should
                  get you the first entry in your application's default
                  font table. 'Helvetica Bold' will give you its second
                  entry, etc.

                  The former wwiinnwwoorrdd66 option is now a deprecated syn-
                  onym for nnooffoonnttlliisstt.  The problems involving the
                  color and font tables that the wwiinnwwoorrdd66 option was
                  intended to work around turned out to be gnuplot bugs
                  which have now been fixed.



             3388..5599..1100..  CCoorreell


             The ccoorreell terminal driver supports CorelDraw.

             Syntax:
                   set terminal corel {  default
                                       | {monochrome | color
                                            {"<font>" {<fontsize>
                                               {<xsize> <ysize>
             {<linewidth> }}}}}

             where the fontsize and linewidth are specified in points
             and the sizes in inches.  The defaults are monochrome,
             "SwitzerlandLight", 22, 8.2, 10 and 1.2.



             3388..5599..1111..  DDeebbuugg


             This terminal is provided to allow for the debugging of
             ggnnuupplloott.  It is likely to be of use only for users who are
             modifying the source code.



             3388..5599..1122..  DDoossppcc


             The ddoossppcc terminal driver supports PCs with arbitrary
             graphics boards, which will be automatically detected.  It
             should be used only if you are not using the gcc or Zortec
             C/C++ compilers.












   GNUPLOT 4.0                                                      157


             3388..5599..1133..  DDuummbb


             The dduummbb terminal driver has an optional size specifica-
             tion and trailing linefeed control.

             Syntax:
                   set terminal dumb {[no]feed} {<xsize> <ysize>}
                                     {[no]enhanced}

             where <xsize> and <ysize> set the size of the dumb termi-
             nals. Default is 79 by 24. The last newline is printed
             only if ffeeeedd is enabled.

             Examples:
                   set term dumb nofeed
                   set term dumb 79 49 # VGA screen---why would anyone
             do that?



             3388..5599..1144..  DDxxff


             The ddxxff terminal driver creates pictures that can be
             imported into AutoCad (Release 10.x).  It has no options
             of its own, but some features of its plots may be modified
             by other means.  The default size is 120x80 AutoCad units,
             which can be changed by sseett ssiizzee.  ddxxff uses seven colors
             (white, red, yellow, green, cyan, blue and magenta), which
             can be changed only by modifying the source file.  If a
             black-and-white plotting device is used, the colors are
             mapped to differing line thicknesses.  See the description
             of the AutoCad print/plot command.



             3388..5599..1155..  DDxxyy880000aa


             This terminal driver supports the Roland DXY800A plotter.
             It has no options.



             3388..5599..1166..  EEeeppiicc


             The eeeeppiicc terminal driver supports the extended LaTeX pic-
             ture environment.  It is an alternative to the llaatteexx
             driver.

             The output of this terminal is intended for use with the










   GNUPLOT 4.0                                                      158


             "eepic.sty" macro package for LaTeX.  To use it, you need
             "eepic.sty", "epic.sty" and a printer driver that supports
             the "tpic" \specials.  If your printer driver doesn't sup-
             port those \specials, "eepicemu.sty" will enable you to
             use some of them.  dvips and dvipdfm do support the "tpic"
             \specials.

             Syntax:
                set terminal eepic {color, dashed, rotate, small, tiny,
             default, <fontsize>}

             Options: You can give options in any order you wish.
             'color' causes gnuplot to produce \color{...} commands so
             that the graphs are colored. Using this option, you must
             include \usepackage{color} in the preambel of your latex
             document.  'dashed' will allow dashed line types; without
             this option, only solid lines with varying thickness will
             be used.  'dashed' and 'color' are mutually exclusive; if
             'color' is specified, then 'dashed' will be ignored.
             'rotate' will enable true rotated text (by 90 degrees).
             Otherwise, rotated text will be typeset with letters
             stacked above each other. If you use this option you must
             include \usepackage{graphicx} in the preamble.  'small'
             will use \scriptsize symbols as point markers (Probably
             does not work with TeX, only LaTeX2e). Default is to use
             the default math size.  'tiny' uses \scriptscriptstyle
             symbols.  'default' resets all options to their defaults =
             no color, no dashed lines, pseudo-rotated (stacked) text,
             large point symbols.  <fontsize> is a number which speci-
             fies the font size inside the picture environment; the
             unit is pt (points), i.e., 10 pt equals approx. 3.5 mm.
             If fontsize is not specified, then all text inside the
             picture will be set in \footnotesize.

             Notes: Remember to escape the # character (or other chars
             meaningful to (La-)TeX) by \\ (2 backslashes).  It seems
             that dashed lines become solid lines when the vertices of
             a plot are too close. (I do not know if that is a general
             problem with the tpic specials, or if it is caused by a
             bug in eepic.sty or dvips/dvipdfm.)  The default size of
             an eepic plot is 5x3 inches, which can be scaled by 'set
             size a,b'.  Points, among other things, are drawn using
             the LaTeX commands "\Diamond", "\Box", etc.  These com-
             mands no longer belong to the LaTeX2e core; they are
             included in the latexsym package, which is part of the
             base distribution and thus part of any LaTeX implementa-
             tion. Please do not forget to use this package.  Instead
             of latexsym, you can also include the amssymb package. All
             drivers for LaTeX offer a special way of controlling text
             positioning: If any text string begins with '{', you also
             need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally.  If the text string begins with '[', you need to










   GNUPLOT 4.0                                                      159


             follow this with a position specification (up to two out
             of t,b,l,r), ']{', the text itself, and finally '}'.  The
             text itself may be anything LaTeX can typeset as an LR-
             box.  '\rule{}{}'s may help for best positioning.

             Examples: set term eepic
               output graphs as eepic macros inside a picture environ-
             ment;
               \input the resulting file in your LaTeX document.
             set term eepic color tiny rotate 8
               eepic macros with \color macros, \scripscriptsize point
             markers,
               true rotated text, and all text set with 8pt.

             About label positioning: Use gnuplot defaults (mostly sen-
             sible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             3388..5599..1177..  EEmmff


             The eemmff terminal generates an Enhanced Metafile Format
             file.  This file format is the metafile standard on MS
             Win32 Systems Syntax:
                   set terminal emf {<color>} {solid | dashed}
                                    {"<font>"} {<fontsize>}

             <color> is either ccoolloorr or mmoonnoocchhrroommee; ssoolliidd draws all
             curves with solid lines, overriding any dashed patterns;
             <font> is the name of a font; and <<ffoonnttssiizzee>> is the size
             of the font in points.

             The first two options can be in any order.  Selecting
             ddeeffaauulltt sets all options to their default values.

             Examples:
                   set terminal emf 'Times Roman Italic' 12
                   set terminal emf color solid    # no pesky dashes!
















   GNUPLOT 4.0                                                      160


             3388..5599..1188..  EEmmxxvvggaa


             The eemmxxvvggaa, eemmxxvveessaa and vvggaall terminal drivers support PCs
             with SVGA, vesa SVGA and VGA graphics boards, respec-
             tively.  They are intended to be compiled with "emx-gcc"
             under either DOS or OS/2.  They also need VESA and SVGAKIT
             maintained by Johannes Martin (JMARTIN@GOOFY.ZDV.UNI-
             MAINZ.DE) with additions by David J. Liu
             (liu@phri.nyu.edu).

             Syntax:
                   set terminal emxvga
                   set terminal emxvesa {vesa-mode}
                   set terminal vgal

             The only option is the vesa mode for eemmxxvveessaa, which
             defaults to G640x480x256.



             3388..5599..1199..  EEppssllaatteexx


             The eeppssllaatteexx driver generates output for further process-
             ing by LaTeX.  Syntax:
                   set terminal epslatex {default}
                                           {color | monochrome} {solid
             | dashed}
                                           {"<fontname>"} {<fontsize>}

             ddeeffaauulltt mode sets all options to their defaults: mmoonnoo--
             cchhrroommee, ddaasshheedd, "default" and 11pt.  Default size of a
             plot is 5 inches wide and 3 inches high.

             ssoolliidd draws all plots with solid lines, overriding any
             dashed patterns; ""<<ffoonnttnnaammee>>"" is the name of font; and
             <<ffoonnttssiizzee>> is the size of the font in PostScript points.
             Font selection isn't supported yet.  Font size selection
             is supported only for the calculation of proper spacing.
             The actual LaTeX font at the point of inclusion is taken,
             so use LaTeX commands for changing fonts. If you use e.g.
             12pt as font size for your LaTeX documents, use '"default"
             12' as options.

             All drivers for LaTeX offer a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can










   GNUPLOT 4.0                                                      161


             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.  See also the documentation for the ppssllaatteexx ter-
             minal driver.  To create multiline labels, use \short-
             stack, for example
                set ylabel '[r]{\shortstack{first line \\ second
             line}}'

             The driver produces two different files, one for the eps
             part of the figure and one for the LaTeX part. The name of
             the eps file is taken from the sseett oouuttppuutt command. The
             name of the LaTeX file is derived by replacing the file
             extension (normally ..eeppss) with ..tteexx instead.  There is no
             LaTeX output if no output file is given!  Remember to
             close the oouuttppuutt ffiillee before leaving ggnnuupplloott.

             In your LaTeX documents use '\input{filename}' to include
             the figure.  The ..eeppss file is included by the command
             \includegraphics{...}, so you must also include \usepack-
             age{graphicx} in the LaTeX preamble.

             Pdf files can be made from the eps file using 'epstopdf'.
             If the graphics package is properly configured, the LaTeX
             files can also be processed by pdflatex without changes,
             using the pdf files instead of the eps files.



             3388..5599..2200..  EEppssoonn--118800ddppii


             This driver supports a family of Epson printers and deriv-
             atives.

             eeppssoonn--118800ddppii and eeppssoonn--6600ddppii are drivers for Epson LQ-
             style 24-pin printers with resolutions of 180 and 60 dots
             per inch, respectively.

             eeppssoonn--llxx880000 is a generic 9-pin driver appropriate for
             printers like the Epson LX-800, the Star NL-10 and
             NX-1000, the PROPRINTER, and so forth.

             nneecc--ccpp66 is generic 24-pin driver that can be used for
             printers like the NEC CP6 and the Epson LQ-800.

             The ookkiiddaattaa driver supports the 9-pin OKIDATA 320/321
             Standard printers.

             The ssttaarrcc driver is for the Star Color Printer.

             The ttaannddyy--6600ddppii driver is for the Tandy DMP-130 series of
             9-pin, 60-dpi printers.

             Only nneecc--ccpp66 has any options.










   GNUPLOT 4.0                                                      162


             Syntax:
                   set terminal nec-cp6 {monochrome | colour | draft}

             which defaults to monochrome.

             With each of these drivers, a binary copy is required on a
             PC to print.  Do not use pprriinntt---use instead ccooppyy ffiillee //bb
             llpptt11::.



             3388..5599..2211..  EExxccll


             The eexxccll terminal driver supports Talaris printers such as
             the EXCL Laser printer and the 1590.  It has no options.



             3388..5599..2222..  FFiigg


             The ffiigg terminal device generates output in the Fig graph-
             ics language.

             Syntax:
                   set terminal fig {monochrome | color}
                                    {landscape | portrait}
                                    {small | big | size <xsize>
             <ysize>}
                                    {metric | inches}
                                    {pointsmax <max_points>}
                                    {solid | dashed}
                                    {fontsize <fsize>}
                                    {textnormal | {textspecial texthid-
             den textrigid}}
                                    {thickness <units>}
                                    {depth <layer>}
                                    {version <number>}

             mmoonnoocchhrroommee and ccoolloorr determine whether the picture is
             black-and-white or ccoolloorr.  ssmmaallll and bbiigg produce a 5x3 or
             8x5 inch graph in the default llaannddssccaappee mode and 3x5 or
             5x8 inches in ppoorrttrraaiitt mode.  ssiizzee sets (overrides) the
             size of the drawing area to <xsize>*<ysize> in units of
             inches or centimeters depending on the iinncchheess or mmeettrriicc
             setting in effect.  The latter settings is also used as
             default units for editing with "xfig".

             ppooiinnttssmmaaxx <<mmaaxx__ppooiinnttss>> sets the maximum number of points
             per polyline.

             ssoolliidd inhibits automatic usage of ddaasshhed lines when solid










   GNUPLOT 4.0                                                      163


             linestyles are used up, which otherwise occurs.

             ffoonnttssiizzee sets the size of the text font to <fsize> points.
             tteexxttnnoorrmmaall resets the text flags and selects postscript
             fonts, tteexxttssppeecciiaall sets the text flags for LaTeX specials,
             tteexxtthhiiddddeenn sets the hidden flag and tteexxttrriiggiidd the rigid
             flag.

             ddeepptthh sets the default depth layer for all lines and text.
             The default depth is 10 to leave room for adding material
             with "xfig" on top of the plot.

             vveerrssiioonn sets the format version of the generated fig out-
             put. Currently only versions 3.1 and 3.2 are supported.

             tthhiicckknneessss sets the default line thickness, which is 1 if
             not specified.  Overriding the thickness can be achieved
             by adding a multiple of 100 to the lliinneettyyppee value for a
             pplloott command.  In a similar way the ddeepptthh of plot elements
             (with respect to the default depth) can be controlled by
             adding a multiple of 1000 to <linetype>.  The depth is
             then <layer> + <linetype>/1000 and the thickness is
             (<linetype>%1000)/100 or, if that is zero, the default
             line thickness.

             Additional point-plot symbols are also available with the
             ffiigg driver. The symbols can be used through ppooiinnttttyyppee val-
             ues % 100 above 50, with different fill intensities con-
             trolled by <pointtype> % 5 and outlines in black (for
             <pointtype> % 10 < 5) or in the current color.  Available
             symbols are
                     50 - 59:  circles
                     60 - 69:  squares
                     70 - 79:  diamonds
                     80 - 89:  upwards triangles
                     90 - 99:  downwards triangles
             The size of these symbols is linked to the font size.  The
             depth of symbols is by default one less than the depth for
             lines to achieve nice error bars.  If <pointtype> is above
             1000, the depth is <layer> + <pointtype>/1000-1.  If
             <pointtype>%1000 is above 100, the fill color is (<point-
             type>%1000)/100-1.

             Available fill colors are (from 1 to 9): black, blue,
             green, cyan, red, magenta, yellow, white and dark blue (in
             monochrome mode: black for 1 to 6 and white for 7 to 9).

             See pplloott wwiitthh for details of <linetype> and <pointtype>.

             The bbiigg option is a substitute for the bbffiigg terminal in
             earlier versions, which is no longer supported.

             Examples:










   GNUPLOT 4.0                                                      164


                   set terminal fig monochrome small pointsmax 1000  #
             defaults

                   plot 'file.dat' with points linetype 102 pointtype
             759
             would produce circles with a blue outline of width 1 and
             yellow fill color.

                   plot 'file.dat' using 1:2:3 with err linetype 1
             pointtype 554
             would produce errorbars with black lines and circles
             filled red.  These circles are one layer above the lines
             (at depth 9 by default).

             To plot the error bars on top of the circles use
                   plot 'file.dat' using 1:2:3 with err linetype 1
             pointtype 2554



             3388..5599..2233..  GGggii


             The ggggii driver can run on different targets as X or
             svgalib.

             Syntax:
                set terminal ggi [acceleration <integer>] [[mode]
             {mode}]

             In X the window cannot be resized using window manager
             handles, but the mode can be given with the mode option,
             e.g.:
              - V1024x768
              - V800x600
              - V640x480
              - V320x200
             Please refer to the ggi documentation for other modes. The
             'mode' keyword is optional. It is recommended to select
             the target by environment variables as explained in the
             libggi manual page. To get DGA on X, you should for exam-
             ple
                bash> export GGI_DISPLAY=DGA
                csh>  setenv GGI_DISPLAY DGA

             'acceleration' is only used for targets which report rela-
             tive pointer motion events (e.g. DGA) and is a strictly
             positive integer multiplication factor for the relative
             distances.  The default for acceleration is 7.

             Examples:
                set term ggi acc 10
                set term ggi acc 1 mode V1024x768










   GNUPLOT 4.0                                                      165


                set term ggi V1024x768



             3388..5599..2244..  GGiiff


             The ggiiff terminal driver generates output in GIF format.
             It uses Thomas Boutell's gd library, which is available
             from http://www.boutell.com/gd/ Support for GIF output was
             removed from the gd library beginning with version 1.6;
             newer versions support PNG output instead.

             Syntax:
                   set terminal gif {transparent} {interlace}
                                    {tiny | small | medium | large |
             giant}
                                    {size <x>,<y>}
                                    {<color0> <color1> <color2> ...}

             ttrraannssppaarreenntt instructs the driver to generate transparent
             GIFs.  The first color will be the transparent one.

             iinntteerrllaaccee instructs the driver to generate interlaced
             GIFs.

             The choice of fonts is ttiinnyy (5x8 pixels), ssmmaallll (6x12 pix-
             els), mmeeddiiuumm (7x13 Bold), llaarrggee (8x16) or ggiiaanntt (9x15 pix-
             els)

             The size <x,y> is given in pixels---it defaults to
             640x480.  The number of pixels can be also modified by
             scaling with the sseett ssiizzee command.

             Each color must be of the form 'xrrggbb', where x is the
             literal character 'x' and 'rrggbb' are the red, green and
             blue components in hex.  For example, 'x00ff00' is green.
             The background color is set first, then the border colors,
             then the X & Y axis colors, then the plotting colors.  The
             maximum number of colors that can be set is 256.

             Examples:
                   set terminal gif small size 640,480 \
                                    xffffff x000000 x404040 \
                                    xff0000 xffa500 x66cdaa xcdb5cd \
                                    xadd8e6 x0000ff xdda0dd x9500d3
             # defaults

             which uses white for the non-transparent background, black
             for borders, gray for the axes, and red, orange, medium
             aquamarine, thistle 3, light blue, blue, plum and dark
             violet for eight plotting colors.











   GNUPLOT 4.0                                                      166


                   set terminal gif transparent xffffff \
                                    x000000 x202020 x404040 x606060 \
                                    x808080 xA0A0A0 xC0C0C0 xE0E0E0

             which uses white for the transparent background, black for
             borders, dark gray for axes, and a gray-scale for the six
             plotting colors.

             The page size is 640x480 pixels.  The ggiiff driver can cre-
             ate either color or monochromatic output, but you have no
             control over which is produced.

             The current version of the ggiiff driver does not support
             animated GIFs.



             3388..5599..2255..  GGnnuuggrraapphh((GGNNUU pplloottuuttiillss))


             The ggnnuuggrraapphh driver produces device-independent output in
             the GNU plot graphics language.  The default size of the
             PostScript results generated by "plot2ps" is 5 x 3 inches;
             this can be increased up to about 8.25 x 8.25 by sseett ssiizzee.

             Syntax:
                   set terminal gnugraph {"<fontname>"} {<fontsize>}
                                         {type <pt>} {size "<size>"}

             which defaults to 10-point "Courier".

             For ttyyppee, the following options are accepted: XX, ppnnmm, ggiiff,
             aaii, ppss, ccggmm, ffiigg, ppccll55, hhppggll, tteekk, and mmeettaa (default). The
             ssiizzee option (default is a4) is passed straight through to
             plotutils, it's the user's responsibility to provide cor-
             rect values. Details can be found in the plotutils docu-
             mentation.

             Examples:
                   set terminal gnugraph type hpgl size "a4"
                   set terminal gnugraph size "a4,xoffset=-5mm,yoff-
             set=2.0cm" type pnm

             There is a non-GNU version of the ggnnuuggrraapphh driver which
             cannot be compiled unless this version is left out.



             3388..5599..2266..  GGppiicc


             The ggppiicc terminal driver generates GPIC graphs in the Free
             Software Foundations's "groff" package.  The default size










   GNUPLOT 4.0                                                      167


             is 5 x 3 inches.  The only option is the origin, which
             defaults to (0,0).

             Syntax:
                   set terminal gpic {<x> <y>}

             where xx and yy are in inches.

             A simple graph can be formatted using

                   groff -p -mpic -Tps file.pic > file.ps.

             The output from pic can be pipe-lined into eqn, so it is
             possible to put complex functions in a graph with the sseett
             llaabbeell and sseett {{xx//yy}}llaabbeell commands.  For instance,

                   set ylab '@space 0 int from 0 to x alpha ( t ) roman
             d t@'

             will label the y axis with a nice integral if formatted
             with the command:

                   gpic filename.pic | geqn -d@@ -Tps | groff -m[macro-
             package] -Tps
                       > filename.ps

             Figures made this way can be scaled to fit into a docu-
             ment.  The pic language is easy to understand, so the
             graphs can be edited by hand if need be.  All co-ordinates
             in the pic-file produced by ggnnuupplloott are given as x+gnu-
             plotx and y+gnuploty.  By default x and y are given the
             value 0.  If this line is removed with an editor in a num-
             ber of files, one can put several graphs in one figure
             like this (default size is 5.0x3.0 inches):

                   .PS 8.0
                   x=0;y=3
                   copy "figa.pic"
                   x=5;y=3
                   copy "figb.pic"
                   x=0;y=0
                   copy "figc.pic"
                   x=5;y=0
                   copy "figd.pic"
                   .PE

             This will produce an 8-inch-wide figure with four graphs
             in two rows on top of each other.

             One can also achieve the same thing by the command

                   set terminal gpic x y











   GNUPLOT 4.0                                                      168


             for example, using

                   .PS 6.0
                   copy "trig.pic"
                   .PE



             3388..5599..2277..  GGpprr


             The ggpprr terminal driver supports the Apollo Graphics Prim-
             itive Resource for a fixed-size window.  It has no
             options.

             If a variable window size is desired, use the aappoolllloo ter-
             minal instead.



             3388..5599..2288..  GGrraassss


             The ggrraassss terminal driver gives ggnnuupplloott capabilities to
             users of the GRASS geographic information system.  Contact
             grassp-list@moon.cecer.army.mil for more information.
             Pages are written to the current frame of the GRASS Graph-
             ics Window.  There are no options.



             3388..5599..2299..  HHeerrccuulleess


             These drivers supports PC monitors with autodetected
             graphics boards.  They can be used only when compiled with
             Zortech C/C++.  None have options.



             3388..5599..3300..  HHpp22662233aa


             The hhpp22662233aa terminal driver supports the Hewlett Packard
             HP2623A.  It has no options.



             3388..5599..3311..  HHpp22664488


             The hhpp22664488 terminal driver supports the Hewlett Packard
             HP2647 and HP2648.  It has no options.










   GNUPLOT 4.0                                                      169


             3388..5599..3322..  HHpp550000cc


             The hhpp550000cc terminal driver supports the Hewlett Packard HP
             DeskJet 500c.  It has options for resolution and compres-
             sion.

             Syntax:
                   set terminal hp500c {<res>} {<comp>}

             where rreess can be 75, 100, 150 or 300 dots per inch and
             ccoommpp can be "rle", or "tiff".  Any other inputs are
             replaced by the defaults, which are 75 dpi and no compres-
             sion.  Rasterization at the higher resolutions may require
             a large amount of memory.



             3388..5599..3333..  HHppggll


             The hhppggll driver produces HPGL output for devices like the
             HP7475A plotter.  There are two options which can be set:
             the number of pens and eejjeecctt, which tells the plotter to
             eject a page when done.  The default is to use 6 pens and
             not to eject the page when done.

             The international character sets ISO-8859-1 and CP850 are
             recognized via sseett eennccooddiinngg iissoo__88885599__11 or sseett eennccooddiinngg
             ccpp885500 (see sseett eennccooddiinngg for details).

             Syntax:
                   set terminal hpgl {<number_of_pens>} {eject}

             The selection

                   set terminal hpgl 8 eject

             is equivalent to the previous hhpp77555500 terminal, and the
             selection

                   set terminal hpgl 4

             is equivalent to the previous hhpp77558800bb terminal.

             The ppccll55 driver supports plotters such as the Hewlett-
             Packard Designjet 750C, the Hewlett-Packard Laserjet III,
             and the Hewlett-Packard Laserjet IV.  It actually uses
             HPGL-2, but there is a name conflict among the terminal
             devices.  It has several options which must be specified
             in the order indicated below:

             Syntax:










   GNUPLOT 4.0                                                      170


                   set terminal pcl5 {mode <mode>} {<plotsize>}
                       {{color {<number_of_pens>}} | monochrome} {solid
             | dashed}
                       {font <font>} {size <fontsize>} {pspoints | nop-
             spoints}

             <mode> is llaannddssccaappee or ppoorrttrraaiitt. <plotsize> is the physi-
             cal plotting size of the plot, which is one of the follow-
             ing: lleetttteerr for standard (8 1/2" X 11") displays, lleeggaall
             for (8 1/2" X 14") displays, nnooeexxtteennddeedd for (36" X 48")
             displays (a letter size ratio) or, eexxtteennddeedd for (36" X
             55") displays (almost a legal size ratio).  ccoolloorr is for
             multi-pen (i.e. color) plots, and <number_of_pens> is the
             number of pens (i.e. colors) used in color plots. mmoonnoo--
             cchhrroommee is for one (e.g. black) pen plots. ssoolliidd draws all
             lines as solid lines, or ddaasshheedd will draw lines with dif-
             ferent dashed and dotted line patterns.  <font> is ssttiicckk,
             uunniivveerrss, ccgg__ttiimmeess, zzaappff__ddiinnggbbaattss, aannttiiqquuee__oolliivvee, aarriiaall,
             ccoouurriieerr, ggaarraammoonndd__aannttiigguuaa, lleetttteerr__ggootthhiicc, ccgg__oommeeggaa, aallbbeerr--
             ttuuss, ttiimmeess__nneeww__rroommaann, ccllaarreennddoonn, ccoorroonneett, mmaarriiggoolldd, ttrruuee--
             ttyyppee__ssyymmbboollss, or wwiinnggddiinnggss. <fontsize> is the font size in
             points.  The point type selection can be the standard
             default set by specifying nnooppssppooiinnttss, or the same set of
             point types found in the postscript terminal by specifying
             ppssppooiinnttss.

             Note that built-in support of some of these options is
             printer device dependent. For instance, all the fonts are
             supposedly supported by the HP Laserjet IV, but only a few
             (e.g. univers, stick) may be supported by the HP Laserjet
             III and the Designjet 750C. Also, color obviously won't
             work on the the laserjets since they are monochrome
             devices.

             Defaults: landscape, noextended, color (6 pens), solid,
             univers, 12 point,
                       and nopspoints.

             With ppccll55 international characters are handled by the
             printer; you just put the appropriate 8-bit character
             codes into the text strings.  You don't need to bother
             with sseett eennccooddiinngg.

             HPGL graphics can be imported by many software packages.



             3388..5599..3344..  HHpplljjiiii


             The hhpplljjiiii terminal driver supports the HP Laserjet Series
             II printer.  The hhppddjj driver supports the HP DeskJet 500
             printer.  These drivers allow a choice of resolutions.










   GNUPLOT 4.0                                                      171


             Syntax:
                   set terminal hpljii | hpdj {<res>}

             where rreess may be 75, 100, 150 or 300 dots per inch; the
             default is 75.  Rasterization at the higher resolutions
             may require a large amount of memory.

             The hhpp550000cc terminal is similar to hhppddjj; hhpp550000cc addition-
             ally supports color and compression.



             3388..5599..3355..  HHppppjj


             The hhppppjj terminal driver supports the HP PaintJet and
             HP3630 printers.  The only option is the choice of font.

             Syntax:
                   set terminal hppj {FNT5X9 | FNT9X17 | FNT13X25}

             with the middle-sized font (FNT9X17) being the default.



             3388..5599..3366..  IImmaaggeenn


             The iimmaaggeenn terminal driver supports Imagen laser printers.
             It is capable of placing multiple graphs on a single page.

             Syntax:
                   set terminal imagen {<fontsize>} {portrait | land-
             scape}
                                       {[<horiz>,<vert>]}

             where ffoonnttssiizzee defaults to 12 points and the layout
             defaults to llaannddssccaappee.  <<hhoorriizz>> and <<vveerrtt>> are the number
             of graphs in the horizontal and vertical directions; these
             default to unity.

             Example:
                   set terminal imagen portrait [2,3]

             puts six graphs on the page in three rows of two in por-
             trait orientation.



             3388..5599..3377..  IIrriiss44dd













   GNUPLOT 4.0                                                      172


             The iirriiss44dd terminal driver supports Silicon Graphics IRIS
             4D computers.  Its only option is 8- or 24-bit color
             depth.  The default is 8.

             Syntax:
                   set terminal iris4d {8 | 24}

             The color depth is not really a choice -- the value appro-
             priate for the hardware should be selected.

             When using 24-bit mode, the colors can be directly speci-
             fied via the file .gnuplot_iris4d that is searched in the
             current directory and then in the home directory specified
             by the HOME environment variable.  This file holds RGB
             values for the background, border, labels and nine plot-
             ting colors, in that order.  For example, here is a file
             containing the default colors:

                   85   85   85     Background   (dark gray)
                   0    0    0      Boundary     (black)
                   170  0    170    Labeling     (magenta)
                   85   255  255    Plot Color 1 (light cyan)
                   170  0    0      Plot Color 2 (red)
                   0    170  0      Plot Color 3 (green)
                   255  85   255    Plot Color 4 (light magenta)
                   255  255  85     Plot Color 5 (yellow)
                   255  85   85     Plot Color 6 (light red)
                   85   255  85     Plot Color 7 (light green)
                   0    170  170    Plot Color 8 (cyan)
                   170  170  0      Plot Color 9 (brown)

             This file must have exactly 12 lines of RGB triples.  No
             empty lines are allowed, and anything after the third num-
             ber on a line is ignored.



             3388..5599..3388..  JJppeegg



             Syntax:
                   set terminal jpeg
                                    {{no}interlace}
                                    {tiny | small | medium | large |
             giant}
                                    {font <face> {<pointsize>}}
                                    {size <x>,<y>} {{no}crop}
                                    {{no}enhanced}
                                    {<color0> <color1> <color2> ...}

             JPEG images are created using libgd, with optional support
             for TrueType fonts via libfreetype.










   GNUPLOT 4.0                                                      173


             The iinntteerrllaaccee option creates a progressive JPEG image.
             Default is nnooiinntteerrllaaccee.

             Five basic fonts are supported directly by the gd library.
             These are ttiinnyy (5x8 pixels), ssmmaallll (6x12 pixels), mmeeddiiuumm,
             (7x13 Bold), llaarrggee (8x16) or ggiiaanntt (9x15 pixels). These
             fonts cannot be scaled or rotated (pure horizontal or ver-
             tical text only).

             If gnuplot was built with support for TrueType (*.ttf) or
             Adobe Type 1 (*.pfa) fonts, they may be selected using the
             'font <face> {<pointsize>}' option. <face> is either the
             full pathname to the font file, or a font face name that
             is assumed to be the first part of a filename in one of
             the directories listed in the GDFONTPATH environmental
             variable. That is, 'set term jpeg font "Face"' will look
             for a font file named either <somedirectory>/Face.ttf or
             <somedirectory>/Face.pfa. Both TrueType and Adobe Type 1
             fonts are fully scalable and may be rotated through any
             angle.  If no font is specified, gnuplot checks the envi-
             ronmental variable GNUPLOT_DEFAULT_GDFONT to see if there
             is a preferred default font.

             eennhhaanncceedd enables the enhanced text processing features,
             (subscripts, superscripts and mixed fonts). See eennhhaanncceedd
             for more information.  The full enhanced mode syntax is
             supported by the PNG/JPEG driver itself, but some of these
             features are dependent on which version of the underlying
             libgd library is present, and which fonts are available.

             The size <x,y> is given in pixels---it defaults to
             640x480.  The number of pixels can be also modified by
             scaling with the sseett ssiizzee command.  ccrroopp trims blank space
             from the edges of the completed plot, resulting in a
             smaller final image size. Default is nnooccrroopp.

             Each color must be of the form 'xrrggbb', where x is the
             literal character 'x' and 'rrggbb' are the red, green and
             blue components in hex.  For example, 'x00ff00' is green.
             The background color is set first, then the border colors,
             then the X & Y axis colors, then the plotting colors.  The
             maximum number of colors that can be set is 256.

             Examples:
                   set terminal jpeg medium size 640,480 \
                                    xffffff x000000 x404040 \
                                    xff0000 xffa500 x66cdaa xcdb5cd \
                                    xadd8e6 x0000ff xdda0dd x9500d3
             # defaults

             which uses white for the non-transparent background, black
             for borders, gray for the axes, and red, orange, medium
             aquamarine, thistle 3, light blue, blue, plum and dark










   GNUPLOT 4.0                                                      174


             violet for eight plotting colors.

                   set terminal jpeg large font arial size 800,600

             which searches for a TrueType font with face name 'arial'
             in the directory specified by the environment variable
             GDFONTPATH and large (14pt) font size.




             3388..5599..3399..  KKyyoo


             The kkyyoo and pprreessccrriibbee terminal drivers support the Kyocera
             laser printer.  The only difference between the two is
             that kkyyoo uses "Helvetica" whereas pprreessccrriibbee uses
             "Courier".  There are no options.



             3388..5599..4400..  LLaatteexx


             The llaatteexx and eemmtteexx drivers allow two options.

             Syntax:
                   set terminal latex | emtex {courier | roman |
             default} {<fontsize>}

             ffoonnttssiizzee may be any size you specify.  The default is for
             the plot to inherit its font setting from the embedding
             document.

             Unless your driver is capable of building fonts at any
             size (e.g. dvips), stick to the standard 10, 11 and 12
             point sizes.

             METAFONT users beware: METAFONT does not like odd sizes.

             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally.  If the text string begins with '[', you need to
             follow this with a position specification (up to two out
             of t,b,l,r), ']{', the text itself, and finally '}'.  The
             text itself may be anything LaTeX can typeset as an LR-
             box.  '\rule{}{}'s may help for best positioning.

             Points, among other things, are drawn using the LaTeX com-
             mands "\Diamond" and "\Box".  These commands no longer
             belong to the LaTeX2e core; they are included in the










   GNUPLOT 4.0                                                      175


             latexsym package, which is part of the base distribution
             and thus part of any LaTeX implementation.  Please do not
             forget to use this package.

             Examples: About label positioning: Use gnuplot defaults
             (mostly sensible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             3388..5599..4411..  LLiinnuuxx


             The lliinnuuxx driver has no additional options to specify.  It
             looks at the environment variable GSVGAMODE for the
             default mode; if not set, it uses 1024x768x256 as default
             mode or, if that is not possible, 640x480x16 (standard
             VGA).



             3388..5599..4422..  MMaacciinnttoosshh


             Several options may be set in the 'macintosh' driver.

             Syntax:
                  set terminal macintosh {singlewin | multiwin} {verti-
             cal | novertical}
                                         {size <width>, <height> |
             default}

             'singlewin' limits the output to a single window and is
             useful for animations.  'multiwin' allows multiple win-
             dows.  'vertical' is only valid under the gx option. With
             this option, rotated text
                 be drawn vertically. novertical turns this option off.
              size <width>, <height> overrides the graph size set in
             the preferences
                 dialog until it is cleared with either 'set term mac
             size default'
                 or 'set term mac default'.

              'set term mac size default' sets the window size settings
             to those set in
                 the preferences dialog.










   GNUPLOT 4.0                                                      176


              'set term mac default' sets all options to their default
             values.
                 Default values: nogx, multiwin, novertical.

              If you generate graphs under the multiwin option and then
             switch to singlewin,
              the next plot command will cause one more window to be
             created. This new
              window will be reused as long as singlewin is in effect.
             If you switch back
              to multiwin, generate some graphs, and then switch to
             singlewin again, the
              orginal 'singlewin' window will be resused if it is still
             open. Otherwise
              a new 'singlewin' window will be created. The 'singlewin'
             window is not numbered.



             3388..5599..4433..  MMff


             The mmff terminal driver creates an input file to the META-
             FONT program.  Thus a figure may be used in the TeX docu-
             ment in the same way as is a character.

             To use a picture in a document, the METAFONT program must
             be run with the output file from ggnnuupplloott as input.  Thus,
             the user needs a basic knowledge of the font creating
             process and the procedure for including a new font in a
             document.  However, if the METAFONT program is set up
             properly at the local site, an unexperienced user could
             perform the operation without much trouble.

             The text support is based on a METAFONT character set.
             Currently the Computer Modern Roman font set is input, but
             the user is in principal free to choose whatever fonts he
             or she needs.  The METAFONT source files for the chosen
             font must be available.  Each character is stored in a
             separate picture variable in METAFONT.  These variables
             may be manipulated (rotated, scaled etc.) when characters
             are needed.  The drawback is the interpretation time in
             the METAFONT program.  On some machines (i.e. PC) the lim-
             ited amount of memory available may also cause problems if
             too many pictures are stored.

             The mmff terminal has no options.
















   GNUPLOT 4.0                                                      177


                  3388..5599..4433..11..  MMEETTAAFFOONNTT IInnssttrruuccttiioonnss



                  - Set your terminal to METAFONT:
                    set terminal mf
                  - Select an output-file, e.g.:
                    set output "myfigures.mf"
                  - Create your pictures. Each picture will generate a
                  separate character. Its default size will be 5*3
                  inches. You can change the size by saying sseett ssiizzee
                  00..55,,00..55 or whatever fraction of the default size you
                  want to have.

                  - Quit ggnnuupplloott.

                  - Generate a TFM and GF file by running METAFONT on
                  the output of ggnnuupplloott.  Since the picture is quite
                  large (5*3 in), you will have to use a version of
                  METAFONT that has a value of at least 150000 for mem-
                  max.  On Unix systems these are conventionally
                  installed under the name bigmf.  For the following
                  assume that the command virmf stands for a big ver-
                  sion of METAFONT.  For example:

                  - Invoke METAFONT:
                      virmf '&plain'
                  - Select the output device: At the METAFONT prompt
                  ('*') type:
                      \mode:=CanonCX;     % or whatever printer you use
                  - Optionally select a magnification:
                      mag:=1;             % or whatever you wish
                  - Input the ggnnuupplloott-file:
                      input myfigures.mf
                  On a typical Unix machine there will usually be a
                  script called "mf" that executes virmf '&plain', so
                  you probably can substitute mf for virmf &plain.
                  This will generate two files: mfput.tfm and
                  mfput.$$$gf (where $$$ indicates the resolution of
                  your device).  The above can be conveniently achieved
                  by typing everything on the command line, e.g.: virmf
                  '&plain' '\mode:=CanonCX; mag:=1; input myfigures.mf'
                  In this case the output files will be named myfig-
                  ures.tfm and myfigures.300gf.

                  - Generate a PK file from the GF file using gftopk:
                    gftopk myfigures.300gf myfigures.300pk
                  The name of the output file for gftopk depends on the
                  DVI driver you use.  Ask your local TeX administrator
                  about the naming conventions.  Next, either install
                  the TFM and PK files in the appropriate directories,
                  or set your environment variables properly.  Usually
                  this involves setting TEXFONTS to include the current










   GNUPLOT 4.0                                                      178


                  directory and doing the same thing for the environ-
                  ment variable that your DVI driver uses (no standard
                  name here...).  This step is necessary so that TeX
                  will find the font metric file and your DVI driver
                  will find the PK file.

                  - To include your pictures in your document you have
                  to tell TeX the font:
                    \font\gnufigs=myfigures
                  Each picture you made is stored in a single charac-
                  ter.  The first picture is character 0, the second is
                  character 1, and so on...  After doing the above
                  step, you can use the pictures just like any other
                  characters.  Therefore, to place pictures 1 and 2
                  centered in your document, all you have to do is:
                    \centerline{\gnufigs\char0}
                    \centerline{\gnufigs\char1}
                  in plain TeX.  For LaTeX you can, of course, use the
                  picture environment and place the picture wherever
                  you wish by using the \makebox and \put macros.

                  This conversion saves you a lot of time once you have
                  generated the font; TeX handles the pictures as char-
                  acters and uses minimal time to place them, and the
                  documents you make change more often than the pic-
                  tures do.  It also saves a lot of TeX memory.  One
                  last advantage of using the METAFONT driver is that
                  the DVI file really remains device independent,
                  because no \special commands are used as in the eepic
                  and tpic drivers.



             3388..5599..4444..  MMggrr


             The mmggrr terminal driver supports the Mgr Window system.
             It has no options.



             3388..5599..4455..  MMiiff


             The mmiiff terminal driver produces Frame Maker MIF format
             version 3.00.  It plots in MIF Frames with the size 15*10
             cm, and plot primitives with the same pen will be grouped
             in the same MIF group.  Plot primitives in a ggnnuupplloott page
             will be plotted in a MIF Frame, and several MIF Frames are
             collected in one large MIF Frame.  The MIF font used for
             text is "Times".

             Several options may be set in the MIF 3.00 driver.










   GNUPLOT 4.0                                                      179


             Syntax:
                   set terminal mif {color | colour | monochrome}
             {polyline | vectors}
                                    {help | ?}

             ccoolloouurr plots lines with line types >= 0 in colour (MIF
             sep. 2--7) and mmoonnoocchhrroommee plots all line types in black
             (MIF sep. 0).  ppoollyylliinnee plots curves as continuous curves
             and vveeccttoorrss plots curves as collections of vectors.  hheellpp
             and ?? print online help on standard error output---both
             print a short description of the usage; hheellpp also lists
             the options.

             Examples:
                   set term mif colour polylines    # defaults
                   set term mif                     # defaults
                   set term mif vectors
                   set term mif help



             3388..5599..4466..  MMpp



             The mmpp driver produces output intended to be input to the
             Metapost program.  Running Metapost on the file creates
             EPS files containing the plots. By default, Metapost
             passes all text through TeX.  This has the advantage of
             allowing essentially  any TeX symbols in titles and
             labels.

             Syntax:
                set term mp {color | colour | monochrome}
                            {solid | dashed}
                            {notex | tex | latex}
                            {magnification <magsize>}
                            {psnfss | psnfss-version7 | nopsnfss}
                            {prologues <value>}
                            {a4paper}
                            {amstex}
                            {"<fontname>"} {<fontsize>}

             The option ccoolloorr causes lines to be drawn in color (on a
             printer or display that supports it), mmoonnoocchhrroommee (or noth-
             ing) selects black lines.  The option ssoolliidd draws solid
             lines, while ddaasshheedd (or nothing) selects lines with dif-
             ferent patterns of dashes.  If ssoolliidd is selected but ccoolloorr
             is not, nearly all lines will be identical.  This may
             occasionally be useful, so it is allowed.

             The option nnootteexx bypasses TeX entirely, therefore no TeX
             code can be used in labels under this option.  This is










   GNUPLOT 4.0                                                      180


             intended for use on old plot files or files that make fre-
             quent use of common characters like $$ and %% that require
             special handling in TeX.

             The option tteexx sets the terminal to output its text for
             TeX to process.

             The option llaatteexx sets the terminal to output its text for
             processing by LaTeX. This allows things like \frac for
             fractions which LaTeX knows about but TeX does not.  Note
             that you must set the environment variable TEX to the name
             of your LaTeX executable (normally latex) if you use this
             option or use mmppoosstt ----tteexx==<<nnaammee ooff LLaaTTeeXX eexxeeccuuttaabbllee>> .......
             Otherwise metapost will try and use TeX to process the
             text and it won't work.

             Changing font sizes in TeX has no effect on the size of
             mathematics, and there is no foolproof way to make such a
             change, except by globally  setting a magnification fac-
             tor. This is the purpose of the mmaaggnniiffiiccaattiioonn option. It
             must be followed by a scaling factor. All text (NOT the
             graphs) will be scaled by this factor. Use this if you
             have math that you want at some size other than the
             default 10pt. Unfortunately, all math will be the same
             size, but see the discussion below on editing the MP out-
             put. mmaagg will also work under nnootteexx but there seems no
             point in using it as the font size option (below) works as
             well.

             The option ppssnnffssss uses postscript fonts in combination
             with LaTeX. Since this option only makes sense, if LaTeX
             is being used, the llaatteexx option is selected automatically.
             This option includes the following packages for LaTeX:
             inputenc(latin1), fontenc(T1), mathptmx, hel-
             vet(scaled=09.2), courier, latexsym and textcomp.

             The option ppssnnffssss--vveerrssiioonn77 uses also postscript fonts in
             LaTeX (option llaatteexx is also automatically selected), but
             uses the following packages with LaTeX: inputenc(latin1),
             fontenc(T1), times, mathptmx, helvet and courier.

             The option nnooppssnnffssss is the default and uses the standard
             font (cmr10 if not otherwise specified).

             The option pprroolloogguueess takes a value as an additional argu-
             ment and adds the line pprroolloogguueess::==<<vvaalluuee>> to the metapost
             file. If a value of 22 is specified metapost uses post-
             script fonts to generate the eps-file, so that the result
             can be viewed using e.g. ghostscript. Normally the output
             of metapost uses TeX fonts and therefore has to be
             included in a (La)TeX file before you can look at it.

             The option nnoopprroolloogguueess is the default. No additional line










   GNUPLOT 4.0                                                      181


             specifying the prologue will be added.

             The option aa44ppaappeerr adds a [[aa44ppaappeerr]] to the documentclass.
             Normally letter paper is used (default). Since this option
             is only used in case of LaTeX, the llaatteexx option is
             selected automatically.

             The option aammsstteexx automatically selects the llaatteexx option
             and includes the following LaTeX packages: amsfonts, ams-
             math(intlimits). By default these packages are not
             included.

             A name in quotes selects the font that will be used when
             no explicit font is given in a sseett llaabbeell or sseett ttiittllee.  A
             name recognized by TeX (a TFM file exists) must be used.
             The default is "cmr10" unless nnootteexx is selected, then it
             is "pcrr8r" (Courier).  Even under nnootteexx, a TFM file is
             needed by Metapost. The file ppccrrrr88rr..ttffmm is the name given
             to Courier in LaTeX's psnfss package.  If you change the
             font from the nnootteexx default, choose a font that matches
             the ASCII encoding at least in the range 32-126.  ccmmtttt1100
             almost works, but it has a nonblank character in position
             32 (space).

             The size can be any number between 5.0 and 99.99.  If it
             is omitted, 10.0 is used.  It is advisable to use mmaaggsstteepp
             sizes: 10 times an integer or half-integer power of 1.2,
             rounded to two decimals, because those are the most avail-
             able sizes of fonts in TeX systems.

             All the options are optional.  If font information is
             given, it must be at the end, with size (if present) last.
             The size is needed to select a size for the font, even if
             the font name includes size information.  For example, sseett
             tteerrmm mmpp ""ccmmtttt1122"" selects cmtt12 shrunk to the default size
             10.  This is probably not what you want or you would have
             used cmtt10.

             The following common ascii characters need special treat-
             ment in TeX:
                $, &, #, %, _;  |, <, >;  ^, ~,  \, {, and }
             The five characters $, #, &, _, and % can simply be
             escaped, e.g., \\$$.  The three characters <, >, and | can
             be wrapped in math mode, e.g., $$<<$$.  The remainder require
             some TeX work-arounds.  Any good book on TeX will give
             some guidance.

             If you type your labels inside double quotes, backslashes
             in TeX code need to be escaped (doubled). Using single
             quotes will avoid having to do this, but then you cannot
             use \\nn for line breaks.  As of this writing, version 3.7
             of gnuplot processes titles given in a pplloott command dif-
             ferently than in other places, and backslashes in TeX










   GNUPLOT 4.0                                                      182


             commands need to be doubled regardless of the style of
             quotes.

             Metapost pictures are typically used in TeX documents.
             Metapost deals with fonts pretty much the same way TeX
             does, which is different from most other document prepara-
             tion programs.  If the picture is included in a LaTeX doc-
             ument using the graphics package, or in a plainTeX docu-
             ment via epsf.tex, and then converted to PostScript with
             dvips (or other dvi-to-ps converter), the text in the plot
             will usually be handled correctly.  However, the text may
             not appear if you send the Metapost output as-is to a
             PostScript interpreter.





                  3388..5599..4466..11..  MMeettaappoosstt IInnssttrruuccttiioonnss



                  - Set your terminal to Metapost, e.g.:
                     set terminal mp mono "cmtt12" 12

                  - Select an output-file, e.g.:
                     set output "figure.mp"

                  - Create your pictures.  Each plot (or multiplot
                  group) will generate a separate Metapost begin-
                  fig...endfig group.  Its default size will be 5 by 3
                  inches.  You can change the size by saying sseett ssiizzee
                  00..55,,00..55 or whatever fraction of the default size you
                  want to have.

                  - Quit gnuplot.

                  - Generate EPS files by running Metapost on the out-
                  put of gnuplot:
                     mpost figure.mp  OR  mp figure.mp
                  The name of the Metapost program depends on the sys-
                  tem, typically mmppoosstt for a Unix machine and mmpp on
                  many others.  Metapost will generate one EPS file for
                  each picture.

                  - To include your pictures in your document you can
                  use the graphics package in LaTeX or epsf.tex in
                  plainTeX:
                     \usepackage{graphics} % LaTeX
                     \input epsf.tex       % plainTeX
                  If you use a driver other than dvips for converting
                  TeX DVI output to PS, you may need to add the follow-
                  ing line in your LaTeX document:










   GNUPLOT 4.0                                                      183


                     \DeclareGraphicsRule{*}{eps}{*}{}
                  Each picture you made is in a separate file.  The
                  first picture is in, e.g., figure.0, the second in
                  figure.1, and so on....  To place the third picture
                  in your document, for example, all you have to do is:
                     \includegraphics{figure.2} % LaTeX
                     \epsfbox{figure.2}         % plainTeX

                  The advantage, if any, of the mp terminal over a
                  postscript terminal is editable output.  Considerable
                  effort went into making this output as clean as pos-
                  sible.  For those knowledgeable in the Metapost lan-
                  guage, the default line types and colors can be
                  changed by editing the arrays lltt[[]] and ccooll[[]].  The
                  choice of solid vs dashed lines, and color vs black
                  lines can be change by changing the values assigned
                  to the booleans ddaasshheeddlliinneess and ccoolloorrlliinneess.  If the
                  default tteexx option was in effect, global changes to
                  the text of labels can be achieved by editing the
                  vveebbaattiimmtteexx......eetteexx block.  In particular, a LaTeX pre-
                  amble can be added if desired, and then LaTeX's
                  built-in size changing commands can be used for maxi-
                  mum flexibility. Be sure to set the appropriate MP
                  configuration variable to force Metapost to run LaTeX
                  instead of plainTeX.



             3388..5599..4477..  MMttooss


             The mmttooss terminal has no options.  It sends data via a
             pipe to an external program called GPCLIENT.  It runs
             under MULTITOS, Magic 3.x, MagicMAC. and MiNT.  If you
             cannot find GPCLIENT, than mail to dirk@lstm.uni-erlan-
             gen.de.



             3388..5599..4488..  NNeexxtt


             Several options may be set in the next driver.

             Syntax:
                   set terminal next {<mode>} {<type> } {<color>}
             {<dashed>}
                              {"<fontname>"} {<fontsize>} title
             {"<newtitle>"}

             where <mode> is  ddeeffaauulltt, which sets all options to their
             defaults; <type> is either nneeww or oolldd, where oolldd invokes
             the old single window; <color> is either ccoolloorr or










   GNUPLOT 4.0                                                      184


             mmoonnoocchhrroommee; <dashed> is either ssoolliidd or ddaasshheedd; "<font-
             name>" is the name of a valid PostScript font; <fontsize>
             is the size of the font in PostScript points; and <title>
             is the title for the GnuTerm window.  Defaults are  nneeww,
             mmoonnoocchhrroommee, ddaasshheedd, "Helvetica", 14pt.

             Examples:
                   set term next default
                   set term next 22
                   set term next color "Times-Roman" 14
                   set term next color "Helvetica" 12 title "MyPlot"
                   set term next old

             Pointsizes may be changed with sseett lliinneessttyyllee.



             3388..5599..4499..  OOppeennsstteepp ((nneexxtt))


             Several options may be set in the openstep (next) driver.

             Syntax:
                   set terminal openstep {<mode>} {<type> } {<color>}
             {<dashed>}
                              {"<fontname>"} {<fontsize>} title
             {"<newtitle>"}

             where <mode> is  ddeeffaauulltt, which sets all options to their
             defaults; <type> is either nneeww or oolldd, where oolldd invokes
             the old single window; <color> is either ccoolloorr or mmoonnoo--
             cchhrroommee; <dashed> is either ssoolliidd or ddaasshheedd; "<fontname>"
             is the name of a valid PostScript font; <fontsize> is the
             size of the font in PostScript points; and <title> is the
             title for the GnuTerm window.  Defaults are  nneeww, mmoonnoo--
             cchhrroommee, ddaasshheedd, "Helvetica", 14pt.

             Examples:
                   set term openstep default
                   set term openstep 22
                   set term openstep color "Times-Roman" 14
                   set term openstep color "Helvetica" 12 title
             "MyPlot"
                   set term openstep old

             Pointsizes may be changed with sseett lliinneessttyyllee.



             3388..5599..5500..  PPbbmm













   GNUPLOT 4.0                                                      185


             Several options may be set in the ppbbmm terminal---the
             driver for PBMplus.

             Syntax:
                   set terminal pbm {<fontsize>} {<mode>}

             where <fontsize> is ssmmaallll, mmeeddiiuumm, or llaarrggee and <mode> is
             mmoonnoocchhrroommee, ggrraayy or ccoolloorr.  The default plot size is 640
             pixels wide and 480 pixels high; this may be changed by
             sseett ssiizzee.

             The output of the ppbbmm driver depends upon <mode>: mmoonnoo--
             cchhrroommee produces a portable bitmap (one bit per pixel),
             ggrraayy a portable graymap (three bits per pixel) and ccoolloorr a
             portable pixmap (color, four bits per pixel).

             The output of this driver can be used with Jef Poskanzer's
             excellent PBMPLUS package, which provides programs to con-
             vert the above PBMPLUS formats to GIF, TIFF, MacPaint,
             Macintosh PICT, PCX, X11 bitmap and many others.  PBMPLUS
             may be obtained from ftp.x.org.  The relevant files have
             names that begin with "netpbm-1mar1994.p1"; they reside in
             /contrib/utilities.  The package can probably also be
             obtained from one of the many sites that mirrors
             ftp.x.org.

             Examples:
                   set terminal pbm small monochrome             #
             defaults
                   set size 2,2; set terminal pbm color medium



             3388..5599..5511..  PPddff


             This terminal produces files in the Adobe Portable Docu-
             ment Format (PDF), useable for printing or display with
             tools like Acrobat Reader

             Syntax:
                   set terminal pdf {fname "<font>"} {fsize <fontsize>}
                                    {{no}enhanced}

             where <font> is the name of the default font to use
             (default Helvetica) and <fontsize> is the font size (in
             points, default 12).

             The eennhhaanncceedd option enables enhanced text processing fea-
             tures (subscripts, superscripts and mixed fonts). See
             eennhhaanncceedd for more information. Only the core PDF fonts are
             supported.











   GNUPLOT 4.0                                                      186


             3388..5599..5522..  PPmm


             The ppmm terminal driver provides an OS/2 Presentation Man-
             ager window in which the graph is plotted.  The window is
             opened when the first graph is plotted.  This window has
             its own online help as well as facilities for printing,
             copying to the clipboard and some line type and color
             adjustments.  The mmuullttiipplloott option is supported.

             Syntax:
                   set terminal pm {server {n}} {persist} {widelines}
             {enhanced} {"title"}

             If ppeerrssiisstt is specified, each graph appears in its own
             window and all windows remain open after ggnnuupplloott exits.
             If sseerrvveerr is specified, all graphs appear in the same win-
             dow, which remains open when ggnnuupplloott exits.  This option
             takes an optional numerical argument which specifies an
             instance of the server process.  Thus multiple server win-
             dows can be in use at the same time.

             If wwiiddeelliinneess is specified, all plots will be drawn with
             wide lines.  If eennhhaanncceedd is specified, sub- and super-
             scripts and multiple fonts are enabled using the same syn-
             tax as the eennhhaanncceedd ppoossttssccrriipptt option (see sseett tteerrmmiinnaall
             ppoossttssccrriipptt eennhhaanncceedd for details).  Font names for the
             basic PostScript fonts may be abbreviated to single let-
             ters.

             If ttiittllee is specified, it will be used as the title of the
             plot window.  It will also be used as the name of the
             server instance, and will override the optional numerical
             argument.

             Linewidths may be changed with sseett lliinneessttyyllee.



             3388..5599..5533..  PPnngg ((NNEEWW))


             Syntax:
                   set terminal png
                          {{no}transparent} {{no}interlace}
                          {tiny | small | medium | large | giant}
                          {font <face> {<pointsize>}}
                          {size <x>,<y>} {{no}crop}
                          {{no}enhanced}
                          {<color0> <color1> <color2> ...}

             PNG images are created using libgd, with optional support
             for TrueType and Adobe Type 1 fonts via libfreetype.










   GNUPLOT 4.0                                                      187


             Version 1.8 or greater of libgd is required.

             ttrraannssppaarreenntt instructs the driver to generate transparent
             PNGs.  The first color will be the transparent one.
             Default is nnoottrraannssppaarreenntt.

             iinntteerrllaaccee instructs the driver to generate interlaced
             PNGs.  Default is nnooiinntteerrllaaccee.

             Five basic fonts are supported directly by the gd library.
             These are ttiinnyy (5x8 pixels), ssmmaallll (6x12 pixels), mmeeddiiuumm,
             (7x13 Bold), llaarrggee (8x16) or ggiiaanntt (9x15 pixels). These
             fonts cannot be scaled or rotated (pure horizontal or ver-
             tical text only).

             If gnuplot was built with support for TrueType (*.ttf) or
             Adobe Type 1 (*.pfa) fonts, they may be selected using the
             'font <face> {<pointsize>}' option. <face> is either the
             full pathname to the font file, or a font face name that
             is assumed to be the first part of a filename in one of
             the directories listed in the GDFONTPATH environmental
             variable. That is, 'set term png font "Face"' will look
             for a font file named either <somedirectory>/Face.ttf or
             <somedirectory>/Face.pfa. Both TrueType and Adobe Type 1
             fonts are fully scalable and may be rotated through any
             angle.  If no font is specified, gnuplot checks the envi-
             ronmental variable GNUPLOT_DEFAULT_GDFONT to see if there
             is a preferred default font.

             eennhhaanncceedd enables the enhanced text processing features,
             (subscripts, superscripts and mixed fonts). See eennhhaanncceedd
             for more information.  The full enhanced mode syntax is
             supported by the PNG/JPEG driver itself, but some of these
             features are dependent on which version of the underlying
             libgd library is present, and which fonts are available.

             The size <x,y> is given in pixels---it defaults to
             640x480.  The number of pixels can be also modified by
             scaling with the sseett ssiizzee command.  ccrroopp trims blank space
             from the edges of the completed plot, resulting in a
             smaller final image size. Default is nnooccrroopp.

             Each color must be of the form 'xrrggbb', where x is the
             literal character 'x' and 'rrggbb' are the red, green and
             blue components in hex.  For example, 'x00ff00' is green.
             The background color is set first, then the border colors,
             then the X & Y axis colors, then the plotting colors.  The
             maximum number of colors that can be set is 256.

             Examples:
                   set terminal png medium size 640,480 \
                                    xffffff x000000 x404040 \
                                    xff0000 xffa500 x66cdaa xcdb5cd \










   GNUPLOT 4.0                                                      188


                                    xadd8e6 x0000ff xdda0dd x9500d3
             # defaults

             which uses white for the non-transparent background, black
             for borders, gray for the axes, and red, orange, medium
             aquamarine, thistle 3, light blue, blue, plum and dark
             violet for eight plotting colors.

                   set terminal png font arial 14 size 800,600

             which searches for a TrueType font with face name 'arial'
             in the directory specified by the environment variable
             GDFONTPATH and 14pt font size.

                   set terminal png transparent xffffff \
                                    x000000 x202020 x404040 x606060 \
                                    x808080 xA0A0A0 xC0C0C0 xE0E0E0

             which uses white for the transparent background, black for
             borders, dark gray for axes, and a gray-scale for the six
             plotting colors.




             3388..5599..5544..  PPnngg ((OOLLDD))


             The ppnngg terminal driver supports Portable Network Graph-
             ics.  This old version of the png driver requires the
             third-party libraries "libpng" and "zlib".  There is a
             newer png driver, with many more features, that is pre-
             ferred if you have libgd version 1.8 or newer.

             Syntax:
                   set terminal png {small | medium | large}
                                    {transparent|notransparent}
                                    {picsize <xsize> <ysize>}
                                    {monochrome | gray | color}
                                    {<color0> <color1> <color2> ...}

             ttrraannssppaarreenntt instructs the driver to generate transparent
             PNGs.  The first color will be the transparent one.

             The defaults are ssmmaallll (fontsize) and ccoolloorr.  Default size
             of the output is 640*480 pixel. This can be changed by the
             option ppiiccssiizzee.

             Each <color> must be of the form 'xrrggbb', where x is the
             literal character 'x' and 'rrggbb' are the red, green and
             blue components in hex.  For example, 'x00ff00' is green.
             The background color is set first, then the border color,
             then the X & Y axis color, then the plotting colors.  The










   GNUPLOT 4.0                                                      189


             maximum number of colors that can be set is currently 99.



             3388..5599..5555..  PPoossttssccrriipptt


             Several options may be set in the ppoossttssccrriipptt driver.

             Syntax:
                   set terminal postscript {<mode>} {enhanced | noen-
             hanced}
                                           {color | colour | mono-
             chrome}
                                           {blacktext | colortext |
             colourtext}
                                           {solid | dashed} {dashlength
             | dl <DL>}
                                           {linewidth | lw <LW>}
                                           {<duplexing>}
                                           {rounded | butt}
                                           {fontfile [add | delete]
             "<filename>"}
                                           {palfuncparam <sam-
             ples>{,<maxdeviation>}}
                                           {"<fontname>"} {<fontsize>}

             where <mode> is llaannddssccaappee, ppoorrttrraaiitt, eeppss or ddeeffaauulltt;
             eennhhaanncceedd enables enhanced text mode features (subscripts,
             superscripts and mixed fonts). See eennhhaanncceedd for more
             information.  Option ccoolloorr enables color; bbllaacckktteexxtt forces
             all text to be written in black even in color mode; ssoolliidd
             draws all plots with solid lines, overriding any dashed
             patterns; ddaasshhlleennggtthh or ddll scales the length of the
             dashed-line segments by <DL> (which is a floating-point
             number greater than zero); lliinneewwiiddtthh or llww scales all
             linewidths by <LW>; <duplexing> is ddeeffaauullttpplleexx, ssiimmpplleexx or
             dduupplleexx ("duplexing" in PostScript is the ability of the
             printer to print on both sides of the same page---don't
             set this if your printer can't do it); rroouunnddeedd sets line
             caps and line joins to be rounded; bbuutttt is the default,
             butt caps and mitered joins; ""<<ffoonnttnnaammee>>"" is the name of a
             valid PostScript font; and <<ffoonnttssiizzee>> is the size of the
             font in PostScript points.  In addition to the standard
             postscript fonts, an oblique version of the Symbol font,
             useful for mathematics, is defined. It is called "Symbol-
             Oblique".

             ddeeffaauulltt mode sets all options to their defaults: llaanndd--
             ssccaappee, mmoonnoocchhrroommee, ddaasshheedd, ddll 11..00, llww 11..00, ddeeffaauullttpplleexx,
             nnooeennhhaanncceedd, "Helvetica" and 14pt.  Default size of a Post-
             Script plot is 10 inches wide and 7 inches high.











   GNUPLOT 4.0                                                      190


             ppaallffuunnccppaarraamm is only available if compiled with ppmm33dd sup-
             port.  It controls how sseett ppaalleettttee ffuunnccttiioonnss are encoded
             as gradients in the output.  Analytic color component
             functions (set via sseett ppaalleettttee ffuunnccttiioonnss) are encoded as
             linear interpolated gradients in the postscript output:
             The color component functions are sampled at <samples>
             points and all points are removed from this gradient which
             can be removed without changing the resulting colors by
             more than <maxdeviation>.  For almost every useful palette
             you may savely leave the defaults of <samples>=2000 and
             <maxdeviation>=0.003 untouched.

             eeppss mode generates EPS (Encapsulated PostScript) output,
             which is just regular PostScript with some additional
             lines that allow the file to be imported into a variety of
             other applications.  (The added lines are PostScript com-
             ment lines, so the file may still be printed by itself.)
             To get EPS output, use the eeppss mode and make only one plot
             per file.  In eeppss mode the whole plot, including the
             fonts, is reduced to half of the default size.

             Fonts listed by ffoonnttffiillee or ffoonnttffiillee aadddd encapsulate the
             font definitions of the listed font from a postscript Type
             1 or TrueType font file directly into the gnuplot output
             postscript file. Thus, the enclosed font can be used in
             labels, titles, etc. See the section ppoossttssccrriipptt ffoonnttffiillee
             for more details.  With ffoonnttffiillee ddeelleettee a fontfile is
             deleted from the list of embedded files.

             Examples:
                   set terminal postscript default       # old post-
             script
                   set terminal postscript enhanced      # old enhpost
                   set terminal postscript landscape 22  # old psbig
                   set terminal postscript eps 14        # old epsf1
                   set terminal postscript eps 22        # old epsf2
                   set size 0.7,1.4; set term post portrait color
             "Times-Roman" 14
                   set term post "VAGRoundedBT_Regular" 14 fontfile
             "bvrr8a.pfa"

             Linewidths and pointsizes may be changed with sseett ssttyyllee
             lliinnee.

             The ppoossttssccrriipptt driver supports about 70 distinct point-
             types, selectable through the ppooiinnttttyyppee option on pplloott and
             sseett ssttyyllee lliinnee.

             Several possibly useful files about ggnnuupplloott's PostScript
             are included in the /docs/psdoc subdirectory of the ggnnuu--
             pplloott distribution and at the distribution sites.  These
             are "ps_symbols.gpi" (a ggnnuupplloott command file that, when
             executed, creates the file "ps_symbols.ps" which shows all










   GNUPLOT 4.0                                                      191


             the symbols available through the ppoossttssccrriipptt terminal),
             "ps_guide.ps" (a PostScript file that contains a summary
             of the enhanced syntax and a page showing what the octal
             codes produce with text and symbol fonts), "ps_file.doc"
             (a text file that contains a discussion of the organiza-
             tion of a PostScript file written by ggnnuupplloott), and
             "ps_fontfile_doc.tex" (a LaTeX file which contains a short
             documentation concerning the encapsulation of LaTeX fonts
             with a glyph table of the math fonts).

             A PostScript file is editable, so once ggnnuupplloott has created
             one, you are free to modify it to your heart's desire.
             See the eeddiittiinngg ppoossttssccrriipptt section for some hints.




                  3388..5599..5555..11..  EEnnhhaanncceedd ppoossttssccrriipptt


                  Several terminal types support an enhanced text mode
                  in which additional formatting information is embed-
                  ded in the text string.






     +--------------------------------------------------------------+
     |Control     Examples      Explanation                         |
     +--------------------------------------------------------------+
     |   ^           a^x        superscript                         |
     |   _           a_x        subscript                           |
     |   @       @x or a@^b_c   phantom box (occupies no width)     |
     |   &         &{space}     inserts space of specified length   |
     |   ~         ~a{.8-}      overprints '-' on 'a', raised by .8 |
     |                          times the current fontsize          |
     +--------------------------------------------------------------+



   Braces can be used to place multiple-character text where a single
   character is expected (e.g., 2^{10}).  To change the font and/or
   size, use the full form:  {/[fontname][=fontsize | *fontscale]
   text}.  Thus {/Symbol=20 G} is a 20-point GAMMA and {/*0.75 K} is a
   K at three-quarters of whatever fontsize is currently in effect.
   (The '/' character MUST be the first character after the '{'.)

   If the encoding vector has been changed by sseett eennccooddiinngg, the default
   encoding vector can be used instead by following the slash with a
   dash.  This is unnecessary if you use the Symbol font, how-
   ever---since /Symbol uses its own encoding vector, ggnnuupplloott will not










   GNUPLOT 4.0                                                      192


   apply any other encoding vector to it.

   The phantom box is useful for a@^b_c to align superscripts and sub-
   scripts but does not work well for overwriting an accent on a let-
   ter.  (To do the latter, it is much better to use 'set encoding
   iso_8859_1' to change to the ISO Latin-1 encoding vector, which con-
   tains a large variety of letters with accents or other diacritical
   marks.)  Since the box is non-spacing, it is sensible to put the
   shorter of the subscript or superscript in the box (that is, after
   the @).

   Space equal in length to a string can be inserted using the '&'
   character.  Thus
           'abc&{def}ghi'
   would produce
           'abc   ghi'.

   The '~' character causes the next character or bracketed text to be
   overprinted by the following character or bracketed text.  The sec-
   ond text will be horizontally centered on the first.  Thus '~a/'
   will result in an 'a' with a slash through it.  You can also shift
   the second text vertically by preceding the second text with a num-
   ber, which will define the fraction of the current fontsize by which
   the text will be raised or lowered.  In this case the number and
   text must be enclosed in brackets because more than one character is
   necessary.  If the overprinted text begins with a number, put a
   space between the vertical offset and the text ('~{abc}{.5 000}');
   otherwise no space is needed ('~{abc}{.5---}').  You can change the
   font for one or both strings ('~a{.5 /*.2 o}'---an 'a' with a one-
   fifth-size 'o' on top---and the space between the number and the
   slash is necessary), but you can't change it after the beginning of
   the string.  Neither can you use any other special syntax within
   either string.  You can, of course, use control characters by escap-
   ing them (see below), such as '~a{\^}'

   You can access special symbols numerically by specifying \character-
   code (in octal), e.g., {/Symbol \245} is the symbol for infinity.

   You can escape control characters using \, e.g.,  \\, \{, and so on.

   But be aware that strings in double-quotes are parsed differently
   than those enclosed in single-quotes.  The major difference is that
   backslashes may need to be doubled when in double-quoted strings.

   Examples (these are hard to describe in words---try them!):
         set xlabel 'Time (10^6 {/Symbol m}s)'
         set title '{/Symbol=18 \362@_{/=9.6 0}^{/=12 x}} \
                    {/Helvetica e^{-{/Symbol m}^2/2} d}{/Symbol m}'

   The file "ps_guide.ps" in the /docs/psdoc subdirectory of the ggnnuu--
   pplloott source distribution contains more examples of the enhanced syn-
   tax.











   GNUPLOT 4.0                                                      193


                  3388..5599..5555..22..  EEddiittiinngg ppoossttssccrriipptt


                  The PostScript language is a very complex lan-
                  guage---far too complex to describe in any detail in
                  this document.  Nevertheless there are some things in
                  a PostScript file written by ggnnuupplloott that can be
                  changed without risk of introducing fatal errors into
                  the file.

                  For example, the PostScript statement "/Color true
                  def" (written into the file in response to the com-
                  mand sseett tteerrmmiinnaall ppoossttssccrriipptt ccoolloorr), may be altered
                  in an obvious way to generate a black-and-white ver-
                  sion of a plot.  Similarly line colors, text colors,
                  line weights and symbol sizes can also be altered in
                  straight-forward ways.  Text (titles and labels) can
                  be edited to correct misspellings or to change fonts.
                  Anything can be repositioned, and of course anything
                  can be added or deleted, but modifications such as
                  these may require deeper knowledge of the PostScript
                  language.

                  The organization of a PostScript file written by ggnnuu--
                  pplloott is discussed in the text file "ps_file.doc" in
                  the docs/ps subdirectory of the gnuplot source dis-
                  tribution.



                  3388..5599..5555..33..  PPoossttssccrriipptt ffoonnttffiillee


                  The ffoonnttffiillee or ffoonnttffiillee aadddd option takes one file
                  name as argument and encapsulates this file into the
                  postscript output in order to make this font avail-
                  able for text elements (labels, tic marks, titles,
                  etc.).  The ffoonnttffiillee ddeelleettee option also takes one
                  file name as argument. It deletes this file name from
                  the list of encapsulated files.

                  The postscript terminal understands some font file
                  formats: Type 1 fonts in ASCII file format (extension
                  ".pfa"), Type 1 fonts in binary file format (exten-
                  sion ".pfb"), and TrueType fonts (extension ".ttf").
                  Pfa files are understood directly, pfb and ttf files
                  are converted on the fly if appropriate conversion
                  tools are installed (see below). You have to specify
                  the full filename with the extension. Each ffoonnttffiillee
                  option takes exact one font file name. This option
                  can be used multiple times in order to include more
                  than one font file.











   GNUPLOT 4.0                                                      194


                  The font file is searched in the working directory
                  and in all directories listed in the fontpath which
                  is determined by sseett ffoonnttppaatthh.  In addition, the
                  fontpath can be set using the environment variable
                  GNUPLOT_FONTPATH. If this is not set a system depen-
                  dent default search list is used. See sseett ffoonnttppaatthh
                  for more details.

                  For using the encapsulated font file you have to
                  specify the font name (which normally is not the same
                  as the file name). When embedding a font file by
                  using the ffoonnttffiillee option in interactive mode, the
                  font name is printed on the screen. E.g.
                     Font file 'p052004l.pfb' contains the font 'URW-
                  PalladioL-Bold'. Location:
                     /usr/lib/X11/fonts/URW/p052004l.pfb

                  When using pfa or pfb fonts, you can also find it out
                  by looking into the font file. There is a line simi-
                  lar to "/FontName /URWPalladioL-Bold def".  The mid-
                  dle string without the slash is the fontname, here
                  "URWPalladioL-Bold".  For TrueType fonts, this is not
                  so easy since the font name is stored in a binary
                  format. In addition, they often have spaces in the
                  font names which is not supported by Type 1 fonts (in
                  which a TrueType is converted on the fly). The font
                  names are changed in order to eliminate the spaces in
                  the fontnames. The easiest way to find out which font
                  name is generated for use with gnuplot, start gnuplot
                  in interactive mode and type in "set terminal post-
                  script fontfile '<filename.ttf>'".

                  For converting font files to pfa format the conver-
                  sion tool has to read the font from a file and write
                  it to standard output.  For pfb files "pfbtops" is a
                  tool which can do this. If this program is installed
                  on your system the on the fly conversion should work.
                  Just try to encapsulate a pfb file. If the compiled
                  in program call does not work correctly you can spec-
                  ify how this program is called by defining the envi-
                  ronment variable GNUPLOT_PFBTOPFA e.g. to "pfbtops
                  %s". The %%ss will be repeated by the font file name
                  and thus has to exist in the string.  If you don't
                  want to do the conversion on the fly but get a pfa
                  file of the font you can use the tool "pfb2pfa" which
                  is written in simple c and should compile with any c
                  compiler.  It is available from many ftp servers,
                  e.g.
                            ftp://ftp.dante.de/tex-archive/fonts/utili-
                  ties/ps2mf/
                  In fact, "pfbtopfa" and "pfb2ps" do the same job.
                  "pfbtopfa" puts the resulting pfa code into a file,
                  whereas "pfbtops" writes it to standard output.










   GNUPLOT 4.0                                                      195


                  TrueType fonts are converted into Type 1 pfa format,
                  e.g.  by using the tool "ttf2pt1" which is available
                  from
                            http://ttf2pt1.sourceforge.net/
                  If the builtin conversion does not work, the conver-
                  sion command can be changed by the environment vari-
                  able GNUPLOT_TTFTOPFA. For usage with ttf2pt1 it may
                  be set to "ttf2pt1 -a -e -W 0 %s - ". Here again, %%ss
                  stands for the file name.

                  For special purposes you also can use a pipe (if
                  available for your operating system). Therefore you
                  start the file name definition with the character "<"
                  and append a program call. This program has to write
                  pfa data to standard output. Thus, a pfa file may be
                  accessed by sseett ffoonnttffiillee ""<< ccaatt ggaarraammoonndd..ppffaa"".

                  For example, including Type 1 font files can be used
                  for including the postscript output in LaTeX docu-
                  ments. The "european computer modern" font (which is
                  a variant of the "computer modern" font) is available
                  in pfb format from any CTAN server, e.g.
                            ftp://ftp.dante.de/tex-archive/fonts/ps-
                  type1/cm-super/
                  For example, the file "sfrm1000.pfb" contains the
                  normal upright fonts with serifs in the design size
                  10pt (font name "SFRM1000").  The computer modern
                  fonts, which are still necessary for mathematics, are
                  available from
                            ftp://ftp.dante.de/tex-archive/fonts/cm/ps-
                  type1/bluesky
                  With these you can use any character available in
                  TeX. However, the computer modern fonts have a
                  strange encoding. (This is why you should not use
                  cmr10.pfb for text, but sfrm1000.pfb instead.)  The
                  usage of TeX fonts is shown in one of the demos.  The
                  file "ps_fontfile_doc.tex" in the /docs/psdoc subdi-
                  rectory of the ggnnuupplloott source distribution contains a
                  table with glyphs of the TeX mathfonts.

                  If the font "CMEX10" is embedded (file "cmex10.pfb")
                  gnuplot defines the additional font "CMEX10-Base-
                  line". It is shifted vertically in order to fit bet-
                  ter to the other glyphs (CMEX10 has its baseline at
                  the top of the symbols).



             3388..5599..5566..  PPssllaatteexx aanndd ppsstteexx


             The ppssllaatteexx and ppsstteexx drivers generate output for further
             processing by LaTeX and TeX, respectively.  Figures










   GNUPLOT 4.0                                                      196


             generated by ppsstteexx can be included in any plain-based for-
             mat (including LaTeX).

             Syntax:
                   set terminal [pslatex | pstex] {<color>} {<dashed>}
             {<rotate>}
                                                  {auxfile}
             {<font_size>}

             <color> is either ccoolloorr or mmoonnoocchhrroommee.  <dashed> is either
             ddaasshheedd or ssoolliidd.  <rotate> is either rroottaattee or nnoorroottaattee
             and determines if the y-axis label is rotated.
             <font_size> is the size (in pts) of the desired font.

             If aauuxxffiillee is specified, it directs the driver to put the
             PostScript commands into an auxiliary file instead of
             directly into the LaTeX file.  This is useful if your pic-
             tures are large enough that dvips cannot handle them.  The
             name of the auxiliary PostScript file is derived from the
             name of the TeX file given on the sseett oouuttppuutt command; it
             is determined by replacing the trailing ..tteexx (actually
             just the final extent in the file name) with ..ppss in the
             output file name, or, if the TeX file has no extension,
             ..ppss is appended.  Remember to close the oouuttppuutt ffiillee before
             leaving ggnnuupplloott.  The ..ppss is included into the ..tteexx file
             by a \special{psfile=...} command.  If you would rather
             prefer \includegraphics{...}, then use the eeppssllaatteexx termi-
             nal.

             All drivers for LaTeX offer a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.

             Examples:
                   set term pslatex monochrome dashed rotate       #
             set to defaults
             To write the PostScript commands into the file "foo.ps":
                   set term pslatex auxfile
                   set output "foo.tex"; plot ...; set output
             About label positioning: Use gnuplot defaults (mostly sen-
             sible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'










   GNUPLOT 4.0                                                      197


             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'

             Linewidths and pointsizes may be changed with sseett ssttyyllee
             lliinnee.



             3388..5599..5577..  PPssttrriicckkss


             The ppssttrriicckkss driver is intended for use with the
             "pstricks.sty" macro package for LaTeX.  It is an alterna-
             tive to the eeeeppiicc and llaatteexx drivers.  You need
             "pstricks.sty", and, of course, a printer that understands
             PostScript, or a converter such as Ghostscript.

             PSTricks is available via anonymous ftp from the /pub
             directory at Princeton.edu.  This driver definitely does
             not come close to using the full capability of the
             PSTricks package.

             Syntax:
                   set terminal pstricks {hacktext | nohacktext} {unit
             | nounit}

             The first option invokes an ugly hack that gives nicer
             numbers; the second has to do with plot scaling.  The
             defaults are hhaacckktteexxtt and nnoouunniitt.



             3388..5599..5588..  QQmmss


             The qqmmss terminal driver supports the QMS/QUIC Laser
             printer, the Talaris 1200 and others.  It has no options.



             3388..5599..5599..  RReeggiiss


             The rreeggiiss terminal device generates output in the REGIS
             graphics language.  It has the option of using 4 (the
             default) or 16 colors.

             Syntax:
                   set terminal regis {4 | 16}













   GNUPLOT 4.0                                                      198


             3388..5599..6600..  RRggiipp


             The rrggiipp and uunniipplleexx terminal drivers support RGIP
             metafiles.  They can combine several graphs on a single
             page, but only one page is allowed in a given output file.

             Syntax:
                   set terminal rgip | uniplex {portrait | landscape}
                                               {[<horiz>,<vert>]}
             {<fontsize>}

             permissible values for the font size are in the range
             1--8, with the default being 1.  The default layout is
             landscape.  Graphs are placed on the page in a hhoorriizzxvveerrtt
             grid, which defaults to [1,1].

             Example:
                   set terminal uniplex portrait [2,3]

             puts six graphs on a page in three rows of two in portrait
             orientation.



             3388..5599..6611..  SSuunn


             The ssuunn terminal driver supports the SunView window sys-
             tem.  It has no options.



             3388..5599..6622..  SSvvgg


             This terminal produces files in the W3C Scalable Vector
             Graphics format.

             Syntax:
                   set terminal svg {size <x> <y> {|fixed|dynamic}}
                                    {fname "<font>"} {fsize <fontsize>}
                                    {{no}enhanced} {fontfile <file-
             name>}

             where <x> and <y> are the size of the SVG plot to gener-
             ate, ddyynnaammiicc allows a svg-Viewer to resize plot, whereas
             the default setting, ffiixxeedd, will request an absolute size.

             <font> is the name of the default font to use (default
             Arial) and <fontsize> is the font size (in points, default
             12). Gnuplot does not currently provide a mechanism for
             embedding fonts in the output file, so svg viewing










   GNUPLOT 4.0                                                      199


             programs may substitute other fonts when the file is dis-
             played.

             The svg terminal supports an enhanced text mode, which
             allows font and other formatting commands to be embedded
             in labels and other text strings. The enhanced text mode
             syntax is shared with other gnuplot terminal types. See
             eennhhaanncceedd for more details.

             SVG allows you to embed fonts directly into an SVG docu-
             ment, or to provide a hypertext link to the desired font.
             The ffoonnttffiillee option specifies a local file which is copied
             into the <defs> section of the resulting SVG output file.
             This file may either itself contain a font, or may contain
             the records necessary to create a hypertext reference to
             the desired font. Gnuplot will look for the requested file
             using the directory list in the GNUPLOT_FONTPATH environ-
             mental variable.



             3388..5599..6633..  SSvvggaa


             The ssvvggaa terminal driver supports PCs with SVGA graphics.
             It can only be used if it is compiled with DJGPP.  Its
             only option is the font.

             Syntax:
                   set terminal svga {"<fontname>"}



             3388..5599..6644..  TTaabbllee


             Instead of producing a graph, the ttaabbllee terminal prints
             out the points on which a graph would be based, i.e., the
             results of processing the pplloott or sspplloott command, in a mul-
             ticolumn ASCII table of X Y {Z} R values.  The character R
             takes on one of three values: "i" if the point is in the
             active range, "o" if it is out-of-range, or "u" if it is
             undefined.  The data format is determined by the format of
             the axis labels (see sseett ffoorrmmaatt), and the columns are sep-
             arated by single spaces.

             For those times when you want the numbers, you can display
             them on the screen or save them to a file.  This can be
             useful if you want to generate contours and then save them
             for further use, perhaps for plotting with pplloott;  see sseett
             ccoonnttoouurr for an example.  The same method can be used to
             save interpolated data (see sseett ssaammpplleess and sseett ddggrriidd33dd).











   GNUPLOT 4.0                                                      200


             3388..5599..6655..  TTeekk4400


             This family of terminal drivers supports a variety of VT-
             like terminals.  tteekk4400xxxx supports Tektronix 4010 and oth-
             ers as well as most TEK emulators; vvtttteekk supports VT-like
             tek40xx terminal emulators; kkcc--tteekk4400xxxx supports MS-DOS
             Kermit Tek4010 terminal emulators in color: kkmm--tteekk4400xxxx
             supports them in monochrome; sseellaannaarr supports Selanar
             graphics; and bbiittggrraapphh supports BBN Bitgraph terminals.
             None have any options.



             3388..5599..6666..  TTeekk441100xx


             The tteekk441100xx terminal driver supports the 410x and 420x
             family of Tektronix terminals.  It has no options.



             3388..5599..6677..  TTeexxddrraaww


             The tteexxddrraaww terminal driver supports the LaTeX texdraw
             environment.  It is intended for use with "texdraw.sty"
             and "texdraw.tex" in the texdraw package.

             Points, among other things, are drawn using the LaTeX com-
             mands "\Diamond" and "\Box".  These commands no longer
             belong to the LaTeX2e core; they are included in the
             latexsym package, which is part of the base distribution
             and thus part of any LaTeX implementation.  Please do not
             forget to use this package.

             It has no options.



             3388..5599..6688..  TTggiiff


             Tgif is an X11-based drawing tool---it has nothing to do
             with GIF.

             The ttggiiff driver supports different pointsizes (with sseett
             ppooiinnttssiizzee), different label fonts and font sizes (e.g. sseett
             llaabbeell ""HHaalllloo"" aatt xx,,yy ffoonntt ""HHeellvveettiiccaa,,3344"") and multiple
             graphs on the page.  The proportions of the axes are not
             changed.

             Syntax:










   GNUPLOT 4.0                                                      201


                   set terminal tgif {portrait | landscape} {<[x,y]>}
                                     {solid | dashed}
                                     {"<fontname>"} {<fontsize>}

             where <[x,y]> specifies the number of graphs in the x and
             y directions on the page, "<fontname>" is the name of a
             valid PostScript font, and <fontsize> specifies the size
             of the PostScript font.  Defaults are ppoorrttrraaiitt, [[11,,11]],
             ddaasshheedd, ""HHeellvveettiiccaa"", and 1188.

             The ssoolliidd option is usually prefered if lines are colored,
             as they often are in the editor.  Hardcopy will be black-
             and-white, so ddaasshheedd should be chosen for that.

             Multiplot is implemented in two different ways.

             The first multiplot implementation is the standard gnuplot
             multiplot feature:

                   set terminal tgif
                   set output "file.obj"
                   set multiplot
                   set origin x01,y01
                   set size  xs,ys
                   plot ...
                        ...
                   set origin x02,y02
                   plot ...
                   set nomultiplot

             See sseett mmuullttiipplloott for further information.

             The second version is the [x,y] option for the driver
             itself.  The advantage of this implementation is that
             everything is scaled and placed automatically without the
             need for setting origins and sizes; the graphs keep their
             natural x/y proportions of 3/2 (or whatever is fixed by
             sseett ssiizzee).

             If both multiplot methods are selected, the standard
             method is chosen and a warning message is given.

             Examples of single plots (or standard multiplot):
                   set terminal tgif                  # defaults
                   set terminal tgif "Times-Roman" 24
                   set terminal tgif landscape
                   set terminal tgif landscape solid

             Examples using the built-in multiplot mechanism:
                   set terminal tgif portrait [2,4]  # portrait; 2
             plots in the x-
                                                     # and 4 in the y-
             direction










   GNUPLOT 4.0                                                      202


                   set terminal tgif [1,2]           # portrait; 1 plot
             in the x-
                                                     # and 2 in the y-
             direction
                   set terminal tgif landscape [3,3] # landscape; 3
             plots in both
                                                     # directions



             3388..5599..6699..  TTkkccaannvvaass


             This terminal driver generates Tk canvas widget commands
             based on Tcl/Tk (default) or Perl.  To use it, rebuild
             ggnnuupplloott (after uncommenting or inserting the appropriate
             line in "term.h"), then

              gnuplot> set term tkcanvas {perltk} {interactive}
              gnuplot> set output 'plot.file'

             After invoking "wish", execute the following sequence of
             Tcl/Tk commands:

              % source plot.file
              % canvas .c
              % pack .c
              % gnuplot .c

             Or, for Perl/Tk use a program like this:

              use Tk;
              my $top = MainWindow->new;
              my $c = $top->Canvas->pack;
              my $gnuplot = do "plot.pl";
              $gnuplot->($c);
              MainLoop;

             The code generated by ggnnuupplloott creates a procedure called
             "gnuplot" that takes the name of a canvas as its argument.
             When the procedure is called, it clears the canvas, finds
             the size of the canvas and draws the plot in it, scaled to
             fit.

             For 2-dimensional plotting (pplloott) two additional proce-
             dures are defined: "gnuplot_plotarea" will return a list
             containing the borders of the plotting area "xleft,
             xright, ytop, ybot" in canvas screen coordinates, while
             the ranges of the two axes "x1min, x1max, y1min, y1max,
             x2min, x2max, y2min, y2max" in plot coordinates can be
             obtained calling "gnuplot_axisranges".  If the "interac-
             tive" option is specified, mouse clicking on a line seg-
             ment will print the coordinates of its midpoint to stdout.










   GNUPLOT 4.0                                                      203


             Advanced actions can happen instead if the user supplies a
             procedure named "user_gnuplot_coordinates", which takes
             the following arguments: "win id x1s y1s x2s y2s x1e y1e
             x2e y2e x1m y1m x2m y2m", the name of the canvas and the
             id of the line segment followed by the coordinates of its
             start and end point in the two possible axis ranges; the
             coordinates of the midpoint are only filled for logarith-
             mic axes.

             The current version of ttkkccaannvvaass supports neither mmuullttiipplloott
             nor rreepplloott.



             3388..5599..7700..  TTppiicc


             The ttppiicc terminal driver supports the LaTeX picture envi-
             ronment with tpic \specials.  It is an alternative to the
             llaatteexx and eeeeppiicc terminal drivers.  Options are the point
             size, line width, and dot-dash interval.

             Syntax:
                   set terminal tpic <pointsize> <linewidth> <interval>

             where ppooiinnttssiizzee and lliinneewwiiddtthh are integers in milli-inches
             and iinntteerrvvaall is a float in inches.  If a non-positive
             value is specified, the default is chosen: pointsize = 40,
             linewidth = 6, interval = 0.1.

             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally by LaTeX. --- If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.

             Examples: About label positioning: Use gnuplot defaults
             (mostly sensible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'












   GNUPLOT 4.0                                                      204


             3388..5599..7711..  UUnniixxppcc


             The uunniixxppcc terminal driver supports AT&T 3b1 and AT&T 7300
             Unix PC.  It has no options.



             3388..5599..7722..  UUnniixxpplloott


             The uunniixxpplloott terminal driver generates output in the Unix
             "plot" graphics language.  It has no options.

             This terminal cannot be compiled if the GNU version of
             plot is to be used; in that case, use the ggnnuuggrraapphh termi-
             nal instead.



             3388..5599..7733..  AAttaarrii SSTT ((vviiaa VVDDII))


             The vvddii terminal is the same as the aattaarrii terminal, except
             that it sends output to the screen via the VDI and not
             into AES-Windows.

             The vvddii terminal has options to set the character size and
             the screen colors.

             Syntax:
                   set terminal vdi {<fontsize>} {<col0> <col1> ...
             <col15>}

             The character size must appear if any colors are to be
             specified.  Each of the (up to 16) colors is given as a
             three-digit hex number, where the digits represent RED,
             GREEN and BLUE (in that order).  The range of 0--15 is
             scaled to whatever color range the screen actually has.
             On a normal ST screen, odd and even intensities are the
             same.

             Examples:
                   set terminal vdi 4    # use small (6x6) font
                   set terminal vdi 6 0  # set monochrome screen to
             white on black
                   set terminal vdi 13 0 fff f00 f0 f ff f0f
                              # set first seven colors to black, white,
             red, green,
                              # blue, cyan, and purple and use large
             font (8x16).

             Additionally, if an environment variable GNUCOLORS exists,










   GNUPLOT 4.0                                                      205


             its contents are interpreted as an options string, but an
             explicit terminal option takes precedence.



             3388..5599..7744..  VVggaaggll


             The vvggaaggll driver is a fast linux console driver with full
             mouse and pm3d support.  It looks at the environment vari-
             able SVGALIB_DEFAULT_MODE for the default mode; if not
             set, it uses a 256 color mode with the highest available
             resolution.

             Syntax:
                set terminal vgagl \
                             background [red] [[green] [blue]] \
                             [uniform | interpolate] \
                             [mode]

             The color mode can also be given with the mode option.
             Both Symbolic names as G1024x768x256 and integers are
             allowed. The bbaacckkggrroouunndd option takes either one or three
             integers in the range [0, 255]. If only one integers is
             supplied, it is taken as gray value for the background.
             If three integers are present, the background gets the
             corresponding color.  The (mutually exclusive) options
             iinntteerrppoollaattee and uunniiffoorrmm control if color interpolation is
             done while drawing triangles (on by default).

             To get high resolution modes, you will probably have to
             modify the configuration file of libvga, usually
             /etc/vga/libvga.conf.  Using the VESA fb is a good choice,
             but this needs to be compiled in the kernel.

             The vgagl driver uses the first *available* vga mode from
             the following list:
              - the driver which was supplied when setting vgagl, e.g.
             `set term vgagl
                G1024x768x256` would first check, if the G1024x768x256
             mode is available.
              - the environment variable SVGALIB_DEFAULT_MODE
              - G1024x768x256
              - G800x600x256
              - G640x480x256
              - G320x200x256
              - G1280x1024x256
              - G1152x864x256
              - G1360x768x256
              - G1600x1200x256













   GNUPLOT 4.0                                                      206


             3388..5599..7755..  VVWWSS


             The VVWWSS terminal driver supports the VAX Windowing System.
             It has no options.  It will sense the display type (mono-
             chrome, gray scale, or color.)  All line styles are plot-
             ted as solid lines.



             3388..5599..7766..  VVxx338844


             The vvxx338844 terminal driver supports the Vectrix 384 and
             Tandy color printers.  It has no options.



             3388..5599..7777..  WWiinnddoowwss


             Three options may be set in the wwiinnddoowwss terminal driver.

             Syntax:
                   set terminal windows {<color>} {"<fontname>"}
             {<fontsize>}

             where <<ccoolloorr>> is either ccoolloorr or mmoonnoocchhrroommee, ""<<ffoonnttnnaammee>>""
             is the name of a valid Windows font, and <<ffoonnttssiizzee>> is the
             size of the font in points.

             Other options may be set with the graph-menu, the initial-
             ization file, and sseett lliinneessttyyllee.  Note that there is one
             restriction imposed by the classic Windows GDI interface:
             modifiable linewidth only works with solid lines, not with
             dotted or dashed ones.

             The Windows version normally terminates immediately as
             soon as the end of any files given as command line argu-
             ments is reached (i.e. in non-interactive mode), unless
             you specify -- as the last command line option.  It will
             also not show the text-window at all, in this mode, only
             the plot.  By giving the optional argument --ppeerrssiisstt (same
             as for gnuplot under x11; former Windows-only options
             //nnooeenndd or --nnooeenndd are still accepted as well), will not
             close gnuplot. Contrary to gnuplot on other operating sys-
             tems, gnuplot's interactive command line is accessible
             after the -persist option.















   GNUPLOT 4.0                                                      207


                  3388..5599..7777..11..  GGrraapphh--mmeennuu


                  The ggnnuupplloott ggrraapphh window has the following options on
                  a pop-up menu accessed by pressing the right mouse
                  button or selecting OOppttiioonnss from the system menu:

                  BBrriinngg ttoo TToopp when checked brings the graph window to
                  the top after every plot.

                  CCoolloorr when checked enables color linestyles.  When
                  unchecked it forces monochrome linestyles.

                  CCooppyy ttoo CClliippbbooaarrdd copies a bitmap and a Metafile pic-
                  ture.

                  BBaacckkggrroouunndd...... sets the window background color.

                  CChhoooossee FFoonntt...... selects the font used in the graphics
                  window.

                  LLiinnee SSttyylleess...... allows customization of the line col-
                  ors and styles.

                  PPrriinntt...... prints the graphics windows using a Windows
                  printer driver and allows selection of the printer
                  and scaling of the output.  The output produced by
                  PPrriinntt is not as good as that from ggnnuupplloott's own
                  printer drivers.

                  UUppddaattee wwggnnuupplloott..iinnii saves the current window loca-
                  tions, window sizes, text window font, text window
                  font size, graph window font, graph window font size,
                  background color and linestyles to the initialization
                  file WWGGNNUUPPLLOOTT..IINNII.



                  3388..5599..7777..22..  PPrriinnttiinngg


                  In order of preference, graphs may be be printed in
                  the following ways.

                  11.. Use the ggnnuupplloott command sseett tteerrmmiinnaall to select a
                  printer and sseett oouuttppuutt to redirect output to a file.

                  22.. Select the PPrriinntt...... command from the ggnnuupplloott ggrraapphh
                  window.  An extra command ssccrreeeenndduummpp does this from
                  the text window.

                  33.. If sseett oouuttppuutt ""PPRRNN"" is used, output will go to a
                  temporary file.  When you exit from ggnnuupplloott or when










   GNUPLOT 4.0                                                      208


                  you change the output with another sseett oouuttppuutt com-
                  mand, a dialog box will appear for you to select a
                  printer port.  If you choose OK, the output will be
                  printed on the selected port, passing unmodified
                  through the print manager.  It is possible to acci-
                  dentally (or deliberately) send printer output meant
                  for one printer to an incompatible printer.



                  3388..5599..7777..33..  TTeexxtt--mmeennuu


                  The ggnnuupplloott tteexxtt window has the following options on
                  a pop-up menu accessed by pressing the right mouse
                  button or selecting OOppttiioonnss from the system menu:

                  CCooppyy ttoo CClliippbbooaarrdd copies marked text to the clip-
                  board.

                  PPaassttee copies text from the clipboard as if typed by
                  the user.

                  CChhoooossee FFoonntt...... selects the font used in the text win-
                  dow.

                  SSyysstteemm CCoolloorrss when selected makes the text window
                  honor the System Colors set using the Control Panel.
                  When unselected, text is black or blue on a white
                  background.

                  UUppddaattee wwggnnuupplloott..iinnii saves the current text window
                  location, text window size, text window font and text
                  window font size to the initialisation file WWGGNNUU--
                  PPLLOOTT..IINNII.

                  MMEENNUU BBAARR

                  If the menu file WWGGNNUUPPLLOOTT..MMNNUU is found in the same
                  directory as WGNUPLOT.EXE, then the menu specified in
                  WWGGNNUUPPLLOOTT..MMNNUU will be loaded.  Menu commands:

                  [Menu] starts a new menu with the name on the follow-
                  ing line.

                  [EndMenu] ends the current menu.

                  [--] inserts a horizontal menu separator.

                  [|] inserts a vertical menu separator.

                  [Button] puts the next macro on a push button instead
                  of a menu.










   GNUPLOT 4.0                                                      209


                  Macros take two lines with the macro name (menu
                  entry) on the first line and the macro on the second
                  line.  Leading spaces are ignored.  Macro commands:

                  [INPUT] --- Input string with prompt terminated by
                  [EOS] or {ENTER}

                  [EOS] --- End Of String terminator.  Generates no
                  output.

                  [OPEN] --- Get name of file to open from list box,
                  with title of list box terminated by [EOS], followed
                  by default filename terminated by [EOS] or {ENTER}.
                  This uses COMMDLG.DLL from Windows 3.1.

                  [SAVE] --- Get name of file to save.  Similar to
                  [OPEN]

                  Macro character substitutions:

                  {ENTER} --- Carriage Return '\r'

                  {TAB} --- Tab '\011'

                  {ESC} --- Escape '\033'

                  {^A} --- '\001'

                  ...

                  {^_} --- '\031'

                  Macros are limited to 256 characters after expansion.



                  3388..5599..7777..44..  WWggnnuupplloott..iinnii


                  Windows ggnnuupplloott will read some of its options from
                  the [[WWGGNNUUPPLLOOTT]] section of WWGGNNUUPPLLOOTT..IINNII in the Windows
                  directory.  A sample WWGGNNUUPPLLOOTT..IINNII file:

                        [WGNUPLOT]
                        TextOrigin=0 0
                        TextSize=640 150
                        TextFont=Terminal,9
                        GraphOrigin=0 150
                        GraphSize=640 330
                        GraphFont=Arial,10
                        GraphColor=1
                        GraphToTop=1
                        GraphBackground=255 255 255










   GNUPLOT 4.0                                                      210


                        Border=0 0 0 0 0
                        Axis=192 192 192 2 2
                        Line1=0 0 255 0 0
                        Line2=0 255 0 0 1
                        Line3=255 0 0 0 2
                        Line4=255 0 255 0 3
                        Line5=0 0 128 0 4

                  The GGrraapphhFFoonntt entry specifies the font name and size
                  in points.  The five numbers given in the BBoorrddeerr,
                  AAxxiiss and LLiinnee entries are the RReedd intensity (0--255),
                  GGrreeeenn intensity, BBlluuee intensity, CCoolloorr LLiinneessttyyllee and
                  MMoonnoo LLiinneessttyyllee.  LLiinneessttyylleess are 0=SOLID, 1=DASH,
                  2=DOT, 3=DASHDOT, 4=DASHDOTDOT.  In the sample WWGGNNUU--
                  PPLLOOTT..IINNII file above, Line 2 is a green solid line in
                  color mode, or a dashed line in monochrome mode.  The
                  default line width is 1 pixel.  If LLiinneessttyyllee is nega-
                  tive, it specifies the width of a SOLID line in pix-
                  els.  Line1 and any linestyle used with the ppooiinnttss
                  style must be SOLID with unit width.



                  3388..5599..7777..55..  WWiinnddoowwss33..00


                  Windows 3.1 is preferred, but WGNUPLOT will run under
                  Windows 3.0 with the following restrictions: 11.. COM-
                  MDLG.DLL and SHELL.DLL (available with Windows 3.1 or
                  Borland C++ 3.1) must be in the windows directory.

                  22.. WGNUPLOT.HLP produced by Borland C++ 3.1 is in
                  Windows 3.1 format.  You need to use the WINHELP.EXE
                  supplied with Borland C++ 3.1.

                  33.. It will not run in real mode due to lack of mem-
                  ory.

                  44.. TrueType fonts are not available in the graph win-
                  dow.

                  55.. Drag-drop does not work.



             3388..5599..7788..  XX1111


             ggnnuupplloott provides the xx1111 terminal type for use with X
             servers.  This terminal type is set automatically at
             startup if the DDIISSPPLLAAYY environment variable is set, if the
             TTEERRMM environment variable is set to xxtteerrmm, or if the --ddiiss--
             ppllaayy command line option is used.










   GNUPLOT 4.0                                                      211


             Syntax:
                set terminal x11 [reset] <n> [[no]enhanced] [font
             <fontspec>]
                                 [title "<string>"] [[no]persist]
             [[no]raise] [close]

             Multiple plot windows are supported: sseett tteerrmmiinnaall xx1111 <<nn>>
             directs the output to plot window number n.  If n>0, the
             terminal number will be appended to the window title
             (unless a title has been supplied manually) and the icon
             will be labeled ggpplltt <<nn>>.  The active window may be dis-
             tinguished by a change in cursor (from default to
             crosshair.)

             The x11 terminal support enhanced text mode (see
             eennhhaanncceedd), subject to the available fonts. In order for
             font size commands embedded in text to have any effect,
             the default x11 font must be scalable. Thus the first
             example below will work as expected, but the second will
             not.

                set term x11 enhanced font "arial,15"
                set title '{\=20 Big} Medium {\=5 Small}'

                set term x11 enhanced font "terminal-14"
                set title '{\=20 Big} Medium {\=5 Small}'

             Plot windows remain open even when the ggnnuupplloott driver is
             changed to a different device.  A plot window can be
             closed by pressing the letter q while that window has
             input focus, or by choosing cclloossee from a window manager
             menu.  All plot windows can be closed by specifying rreesseett,
             which actually terminates the subprocess which maintains
             the windows (unless --ppeerrssiisstt was specified).  The cclloossee
             command can be used to close individual plot windows by
             number.  However, after a rreesseett, those plot windows left
             due to persist cannot be closed with the command cclloossee.  A
             cclloossee without a number closes the current active plot win-
             dow.

             The gnuplot outboard driver, gnuplot_x11, is searched in a
             default place chosen when the program is compiled.  You
             can override that by defining the environment variable
             GNUPLOT_DRIVER_DIR to point to a different location.

             Plot windows will automatically be closed at the end of
             the session unless the --ppeerrssiisstt option was given.

             The options ppeerrssiisstt and rraaiissee are unset by default, which
             means that the defaults (persist == no and raise == yes)
             or the command line options -persist / -raise or the Xre-
             sources are taken.  If [no]persist or [no]raise are speci-
             fied, they will override command line options and










   GNUPLOT 4.0                                                      212


             Xresources.  Setting one of these options takes place
             immediately, so the behaviour of an already running driver
             can be modified.

             The option ttiittllee ""<<ttiittllee nnaammee>>"" will supply the title name
             of the window for the current plot window or plot window
             <n> if a number is given.  Where (or if) this title is
             shown depends on your X window manager.

             The size or aspect ratio of a plot may be changed by
             resizing the ggnnuupplloott window.

             Linewidths and pointsizes may be changed from within ggnnuu--
             pplloott with sseett lliinneessttyyllee.

             For terminal type xx1111, ggnnuupplloott accepts (when initialized)
             the standard X Toolkit options and resources such as geom-
             etry, font, and name from the command line arguments or a
             configuration file.  See the X(1) man page (or its equiva-
             lent) for a description of such options.

             A number of other ggnnuupplloott options are available for the
             xx1111 terminal.  These may be specified either as command-
             line options when ggnnuupplloott is invoked or as resources in
             the configuration file ".Xdefaults".  They are set upon
             initialization and cannot be altered during a ggnnuupplloott ses-
             sion.  (except ppeerrssiisstt and rraaiissee)




                  3388..5599..7788..11..  XX1111__ffoonnttss


                  Upon initial startup, the default font is taken from
                  the X11 resources as set in the system or user .Xde-
                  faults file or on the command line.

                  Example:
                        gnuplot*font: lucidasans-bold-12
                  A new default font may be specified to the x11 driver
                  from inside gnuplot using
                       `set term x11 font "<fontspec>"`
                  The driver first queries the X-server for a font of
                  the exact name given, for example sseett tteerrmm xx1111 ffoonntt
                  ""lluucciiddaassaannss--1100"". If this query fails, then it tries
                  to interpret <fontspec> as
                  "<font>,<size>,<slant>,<weight>" and to construct a
                  full X11 font name of the form
                        -*-<font>-<weight>-<s>-*-*-<size>-*-*-*-*-*-<encod-
                  ing>

                   <font> is the base name of the font (e.g. Times or










   GNUPLOT 4.0                                                      213


                  Symbol)
                   <size> is the point size (defaults to 12 if not
                  specified)
                   <s> is `i` if <slant>=="italic" `o` if
                  <slant>=="oblique" `r` otherwise
                   <weight> is `medium` or `bold` if explicitly
                  requested, otherwise `*`
                   <encoding> is set based on the current character set
                  (see help for `set encoding`).
                  So sseett tteerrmm xx1111 ffoonntt ""aarriiaall,,1155,,iittaalliicc"" will be trans-
                  lated to -*-arial-*-i-*-*-15-*-*-*-*-*-iso8859-1
                  (assuming default encoding).  The <size>, <slant>,
                  and <weight> specifications are all optional.  If you
                  do not specify <slant> or <weight> then you will get
                  whatever font variant the font server offers first.
                  The driver also recognizes some common PostScript
                  font names and replaces them with possible X11 or
                  TrueType equivalents.  This same sequence is used to
                  process font requests from sseett llaabbeell.



                  3388..5599..7788..22..  CCoommmmaanndd--lliinnee__ooppttiioonnss


                  In addition to the X Toolkit options, the following
                  options may be specified on the command line when
                  starting ggnnuupplloott or as resources in your ".Xdefaults"
                  file (note that rraaiissee and ppeerrssiisstt can be overridden
                  later by sseett tteerrmm xx1111 [[nnoo]]rraaiissee [[nnoo]]ppeerrssiisstt)):



   +-----------------------------------------------------------------------------+
   |  `-mono`      forces monochrome rendering on color displays.                |
   |  `-gray`      requests grayscale rendering on grayscale or color displays.  |
   |               (Grayscale displays receive monochrome rendering by default.) |
   |  `-clear`     requests that the window be cleared momentarily before a      |
   |               new plot is displayed.                                        |
   |  `-tvtwm`     requests that geometry specifications for position of the     |
   |               window be made relative to the currently displayed portion    |
   |               of the virtual root.                                          |
   |  `-raise`     raises plot window after each plot                            |
   | `-noraise`    does not raise plot window after each plot                    |
   |`-novevents`   does not process mouse and key events                         |
   | `-persist`    plot windows survive after main gnuplot program exits         |
   +-----------------------------------------------------------------------------+


   The options are shown above in their command-line syntax.  When
   entered as resources in ".Xdefaults", they require a different syn-
   tax.











   GNUPLOT 4.0                                                      214


   Example:
         gnuplot*gray: on

   ggnnuupplloott also provides a command line option (--ppooiinnttssiizzee <<vv>>) and a
   resource, ggnnuupplloott**ppooiinnttssiizzee:: <<vv>>, to control the size of points
   plotted with the ppooiinnttss plotting style.  The value vv is a real num-
   ber (greater than 0 and less than or equal to ten) used as a scaling
   factor for point sizes.  For example, --ppooiinnttssiizzee 22 uses points twice
   the default size, and --ppooiinnttssiizzee 00..55 uses points half the normal
   size.

   The --nnooeevveennttss switch disables all mouse and key event processing
   (except for qq and <<ssppaaccee>> for closing the window). This is useful
   for programs which use the x11 driver independent of the gnuplot
   main program.



                  3388..5599..7788..33..  MMoonnoocchhrroommee__ooppttiioonnss


                  For monochrome displays, ggnnuupplloott does not honor fore-
                  ground or background colors.  The default is black-
                  on-white.  --rrvv or ggnnuupplloott**rreevveerrsseeVViiddeeoo:: oonn requests
                  white-on-black.




                  3388..5599..7788..44..  CCoolloorr__rreessoouurrcceess


                  For color displays, ggnnuupplloott honors the following
                  resources (shown here with their default values) or
                  the greyscale resources.  The values may be color
                  names as listed in the X11 rgb.txt file on your sys-
                  tem, hexadecimal RGB color specifications (see X11
                  documentation), or a color name followed by a comma
                  and an iinntteennssiittyy value from 0 to 1.  For example,
                  bblluuee,, 00..55 means a half intensity blue.























   GNUPLOT 4.0                                                      215


                    +--------------------------------+
                    |    gnuplot*background: white   |
                    |    gnuplot*textColor: black    |
                    |    gnuplot*borderColor: black  |
                    |    gnuplot*axisColor: black    |
                    |    gnuplot*line1Color: red     |
                    |    gnuplot*line2Color: green   |
                    |    gnuplot*line3Color: blue    |
                    |    gnuplot*line4Color: magenta |
                    |    gnuplot*line5Color: cyan    |
                    |    gnuplot*line6Color: sienna  |
                    |    gnuplot*line7Color: orange  |
                    |    gnuplot*line8Color: coral   |
                    +--------------------------------+



   The command-line syntax for these is simple only for background,
   which maps directly to the usual X11 toolkit option "-bg".  All oth-
   ers can only be set on the command line by use of the generic "-xrm"
   resource override option

   Examples:

         gnuplot -background coral
   to change the background color.

         gnuplot -xrm 'gnuplot*line1Color:blue'
   to override the first linetype color.




                  3388..5599..7788..55..  GGrraayyssccaallee__rreessoouurrcceess


                  When --ggrraayy is selected, ggnnuupplloott honors the following
                  resources for grayscale or color displays (shown here
                  with their default values).  Note that the default
                  background is black.























   GNUPLOT 4.0                                                      216


                     +-------------------------------+
                     |    gnuplot*background: black  |
                     |    gnuplot*textGray: white    |
                     |    gnuplot*borderGray: gray50 |
                     |    gnuplot*axisGray: gray50   |
                     |    gnuplot*line1Gray: gray100 |
                     |    gnuplot*line2Gray: gray60  |
                     |    gnuplot*line3Gray: gray80  |
                     |    gnuplot*line4Gray: gray40  |
                     |    gnuplot*line5Gray: gray90  |
                     |    gnuplot*line6Gray: gray50  |
                     |    gnuplot*line7Gray: gray70  |
                     |    gnuplot*line8Gray: gray30  |
                     +-------------------------------+






                  3388..5599..7788..66..  LLiinnee__rreessoouurrcceess


                  ggnnuupplloott honors the following resources for setting
                  the width (in pixels) of plot lines (shown here with
                  their default values.)  0 or 1 means a minimal width
                  line of 1 pixel width.  A value of 2 or 3 may improve
                  the appearance of some plots.



                       +---------------------------+
                       |    gnuplot*borderWidth: 2 |
                       |    gnuplot*axisWidth: 0   |
                       |    gnuplot*line1Width: 0  |
                       |    gnuplot*line2Width: 0  |
                       |    gnuplot*line3Width: 0  |
                       |    gnuplot*line4Width: 0  |
                       |    gnuplot*line5Width: 0  |
                       |    gnuplot*line6Width: 0  |
                       |    gnuplot*line7Width: 0  |
                       |    gnuplot*line8Width: 0  |
                       +---------------------------+



   ggnnuupplloott honors the following resources for setting the dash style
   used for plotting lines.  0 means a solid line.  A two-digit number
   jjkk (jj and kk are >= 1  and <= 9) means a dashed line with a repeated
   pattern of jj pixels on followed by kk pixels off.  For example, '16'
   is a "dotted" line with one pixel on followed by six pixels off.
   More elaborate on/off patterns can be specified with a four-digit
   value.  For example, '4441' is four on, four off, four on, one off.










   GNUPLOT 4.0                                                      217


   The default values shown below are for monochrome displays or mono-
   chrome rendering on color or grayscale displays.  For color dis-
   plays, the default for each is 0 (solid line) except for aaxxiissDDaasshheess
   which defaults to a '16' dotted line.



                     +------------------------------+
                     |    gnuplot*borderDashes: 0   |
                     |    gnuplot*axisDashes: 16    |
                     |    gnuplot*line1Dashes: 0    |
                     |    gnuplot*line2Dashes: 42   |
                     |    gnuplot*line3Dashes: 13   |
                     |    gnuplot*line4Dashes: 44   |
                     |    gnuplot*line5Dashes: 15   |
                     |    gnuplot*line6Dashes: 4441 |
                     |    gnuplot*line7Dashes: 42   |
                     |    gnuplot*line8Dashes: 13   |
                     +------------------------------+






                  3388..5599..7788..77..  XX1111 ppmm33dd__rreessoouurrcceess


                  Choosing the appropriate visual class and number of
                  colors is a crucial point in X11 applications and a
                  bit awkward, since X11 supports six visual types in
                  different depths.

                  By default ggnnuupplloott uses the default visual of the
                  screen. The number of colors which can be allocated
                  depends on the visual class chosen. On a visual class
                  with a depth > 12bit, gnuplot starts with a maximal
                  number of 0x200 colors.  On a visual class with a
                  depth > 8bit (but <= 12 bit) the maximal number of
                  colors is 0x100, on <= 8bit displays the maximum num-
                  ber of colors is 240 (16 are left for line colors).

                  Gnuplot first starts to allocate the maximal number
                  of colors as stated above.  If this fails, the number
                  of colors is reduced by the factor 2 until gnuplot
                  gets all colors which are requested. If dividing mmaaxx--
                  ccoolloorrss by 2 repeatedly results in a number which is
                  smaller than mmiinnccoolloorrss ggnnuupplloott tries to install a
                  private colormap. In this case the window manager is
                  responsible for swapping colormaps when the pointer
                  is moved in and out the x11 driver's window.

                  The default for mmiinnccoolloorrss is maxcolors /










   GNUPLOT 4.0                                                      218


                  (num_colormaps > 1 ? 2 : 8), where num_colormaps is
                  the number of colormaps which are currently used by
                  gnuplot (usually 1, if only one x11 window is open).

                  Some systems support multiple (different) visual
                  classes together on one screen. On these systems it
                  might be necessary to force gnuplot to use a specific
                  visual class, e.g. the default visual might be 8bit
                  PseudoColor but the screen would also support 24bit
                  TrueColor which would be the preferred choice.

                  The information about an Xserver's capabilities can
                  be obtained with the program xxddppyyiinnffoo.  For the
                  visual names below you can choose one of StaticGray,
                  GrayScale, StaticColor, PseudoColor, TrueColor,
                  DirectColor.  If an Xserver supports a requested
                  visual type at different depths, ggnnuupplloott chooses the
                  visual class with the highest depth (deepest).  If
                  the requested visual class matches the default visual
                  and multiple classes of this type are supported, the
                  default visual is preferred.

                  Example: on an 8bit PseudoColor visual you can force
                  a private color map by specifying ggnnuupplloott**mmaaxxccoolloorrss::
                  224400 and ggnnuupplloott**mmiinnccoolloorrss:: 224400.




                +-----------------------------------------+
                |    gnuplot*maxcolors:  <integer number> |
                |    gnuplot*mincolors:  <integer number> |
                |    gnuplot*visual:     <visual name>    |
                +-----------------------------------------+





             3388..5599..7799..  XXlliibb


             The xxlliibb terminal driver supports the X11 Windows System.
             It generates gnuplot_x11 commands, but sends them to the
             output file specified by sseett oouuttppuutt ''<<ffiilleennaammee>>''. sseett tteerrmm
             xx1111 is equivalent to sseett tteerrmmiinnaall xxlliibb;; sseett oouuttppuutt ""||ggnnuu--
             pplloott__xx1111 --nnooeevveennttss"".  xxlliibb takes the same set of options
             as xx1111.















   GNUPLOT 4.0                                                      219


        3388..6600..  TTiiccss


        The sseett ttiiccss command can be used to change the tics to be drawn
        outwards.

        Syntax:
              set tics {<direction>}
              show tics

        where <direction> may be iinn (the default) or oouutt.

        See also sseett xxttiiccss for more control of major (labelled) tic
        marks and sseett mmxxttiiccss for control of minor tic marks.



        3388..6611..  TTiiccsslleevveell


        Using sspplloott, one can adjust the relative height of the vertical
        (Z) axis using sseett ttiiccsslleevveell.  The numeric argument provided
        specifies the location of the bottom of the scale (as a frac-
        tion of the z-range) above the xy-plane.  The default value is
        0.5.  Negative values are permitted, but tic labels on the
        three axes may overlap.

        To place the xy-plane at a position 'pos' on the z-axis, ttiicc--
        sslleevveell should be set equal to  (pos - zmin) / (zmin - zmax).

        Syntax:
              set ticslevel {<level>}
              show tics

        See also sseett vviieeww.



        3388..6622..  TTiiccssccaallee


        The size of the tic marks can be adjusted with sseett ttiiccssccaallee.

        Syntax:
              set ticscale {<major> {<minor>}}
              show tics

        If <minor> is not specified, it is 0.5*<major>.  The default
        size is 1.0 for major tics and 0.5 for minor tics.  Note that
        it is possible to have the tic marks pointing outward by speci-
        fying a negative size.












   GNUPLOT 4.0                                                      220


        3388..6633..  TTiimmeessttaammpp


        The command sseett ttiimmeessttaammpp places the time and date of the plot
        in the left margin.

        Syntax:
              set timestamp {"<format>"} {top|bottom} {{no}rotate}
                            {<xoff>}{,<yoff>} {"<font>"}
              unset timestamp
              show timestamp

        The format string allows you to choose the format used to write
        the date and time.  Its default value is what asctime() uses:
        "%a %b %d %H:%M:%S %Y" (weekday, month name, day of the month,
        hours, minutes, seconds, four-digit year).  With ttoopp or bboottttoomm
        you can place the timestamp at the top or bottom of the left
        margin (default: bottom).  rroottaattee lets you write the timestamp
        vertically, if your terminal supports vertical text.  The con-
        stants <xoff> and <yoff> are offsets from the default position
        given in character screen coordinates.  <font> is used to spec-
        ify the font with which the time is to be written.

        The abbreviation ttiimmee may be used in place of ttiimmeessttaammpp.

        Example:
              set timestamp "%d/%m/%y %H:%M" 80,-2 "Helvetica"

        See sseett ttiimmeeffmmtt for more information about time format strings.



        3388..6644..  TTiimmeeffmmtt


        This command applies to timeseries where data are composed of
        dates/times.  It has no meaning unless the command sseett xxddaattaa
        ttiimmee is given also.

        Syntax:
              set timefmt "<format string>"
              show timefmt

        The string argument tells ggnnuupplloott how to read timedata from the
        datafile.  The valid formats are:


















   GNUPLOT 4.0                                                      221


     +---------------------------------------------------------------+
     |Format   Explanation                                           |
     +---------------------------------------------------------------+
     |  %d     day of the month, 1--31                               |
     |  %m     month of the year, 1--12                              |
     |  %y     year, 0--99                                           |
     |  %Y     year, 4-digit                                         |
     |  %j     day of the year, 1--365                               |
     |  %H     hour, 0--24                                           |
     |  %M     minute, 0--60                                         |
     |  %s     seconds since the Unix epoch (1970-01-01 00:00 UTC)   |
     |  %S     second, 0--60                                         |
     |  %b     three-character abbreviation of the name of the month |
     |  %B     name of the month                                     |
     +---------------------------------------------------------------+
     +---------------------------------------------------------------+


   Any character is allowed in the string, but must match exactly.  \t
   (tab) is recognized.  Backslash-octals (\nnn) are converted to char.
   If there is no separating character between the time/date elements,
   then %d, %m, %y, %H, %M and %S read two digits each, %Y reads four
   digits and %j reads three digits.  %b requires three characters, and
   %B requires as many as it needs.

   Spaces are treated slightly differently.  A space in the string
   stands for zero or more whitespace characters in the file.  That is,
   "%H %M" can be used to read "1220" and "12     20" as well as "12
   20".

   Each set of non-blank characters in the timedata counts as one col-
   umn in the uussiinngg nn::nn specification.  Thus 1111::1111  2255//1122//7766  2211..00 con-
   sists of three columns.  To avoid confusion, ggnnuupplloott requires that
   you provide a complete uussiinngg specification if your file contains
   timedata.

   Since ggnnuupplloott cannot read non-numerical text, if the date format
   includes the day or month in words, the format string must exclude
   this text.  But it can still be printed with the "%a", "%A", "%b",
   or "%B" specifier: see sseett ffoorrmmaatt for more details about these and
   other options for printing timedata.  (ggnnuupplloott will determine the
   proper month and weekday from the numerical values.)

   See also sseett xxddaattaa and TTiimmee//ddaattee for more information.

   Example:
         set timefmt "%d/%m/%Y\t%H:%M"
   tells ggnnuupplloott to read date and time separated by tab.  (But look
   closely at your data---what began as a tab may have been converted
   to spaces somewhere along the line; the format string must match
   what is actually in the file.)  See also time data demo.












   GNUPLOT 4.0                                                      222


        3388..6655..  TTiittllee


        The sseett ttiittllee command produces a plot title that is centered at
        the top of the plot.  sseett ttiittllee is a special case of sseett llaabbeell.

        Syntax:
              set title {"<title-text>"} {<xoff>}{,<yoff>}
        {"<font>{,<size>}"}
                        {{textcolor | tc} {lt <line_type> | default}}
              show title

        Specifying constants <xoff> or <yoff> as optional offsets for
        the title will move the title <xoff> or <yoff> character screen
        coordinates (not graph coordinates).  For example, "sseett ttiittllee
        ,,--11" will change only the y offset of the title, moving the
        title down by roughly the height of one character.

        <font> is used to specify the font with which the title is to
        be written; the units of the font <size> depend upon which ter-
        minal is used.

        tteexxttccoolloorr lltt <<nn>> sets the text color to that of line type <n>.

        sseett ttiittllee with no parameters clears the title.

        See ssyynnttaaxx for details about the processing of backslash
        sequences and the distinction between single- and double-
        quotes.



        3388..6666..  TTmmaarrggiinn


        The command sseett ttmmaarrggiinn sets the size of the top margin.
        Please see sseett mmaarrggiinn for details.



        3388..6677..  TTrraannggee


        The sseett ttrraannggee command sets the parametric range used to com-
        pute x and y values when in parametric or polar modes.  Please
        see sseett xxrraannggee for details.



        3388..6688..  UUrraannggee













   GNUPLOT 4.0                                                      223


        The sseett uurraannggee and sseett vvrraannggee commands set the parametric
        ranges used to compute x, y, and z values when in sspplloott para-
        metric mode.  Please see sseett xxrraannggee for details.



        3388..6699..  VVaarriiaabblleess


        The sshhooww vvaarriiaabblleess command lists all user-defined variables and
        their values.

        Syntax:
              show variables



        3388..7700..  VVeerrssiioonn


        The sshhooww vveerrssiioonn command lists the version of gnuplot being
        run, its last modification date, the copyright holders, and
        email addresses for the FAQ, the gnuplot-info mailing list, and
        reporting bugs--in short, the information listed on the screen
        when the program is invoked interactively.

        Syntax:
              show version {long}

        When the lloonngg option is given, it also lists the operating sys-
        tem, the compilation options used when ggnnuupplloott was installed,
        the location of the help file, and (again) the useful email
        addresses.



        3388..7711..  VViieeww


        The sseett vviieeww command sets the viewing angle for ssppllootts.  It
        controls how the 3-d coordinates of the plot are mapped into
        the 2-d screen space.  It provides controls for both rotation
        and scaling of the plotted data, but supports orthographic pro-
        jections only.  It supports both 3D projection or orthogonal 2D
        projection into a 2D plot-like map.

        Syntax:
              set view { <rot_x>{,{<rot_z>}{,{<scale>}{,<scale_z>}}} |
        map }
              show view

        where <rot_x> and <rot_z> control the rotation angles (in
        degrees) in a virtual 3-d coordinate system aligned with the










   GNUPLOT 4.0                                                      224


        screen such that initially (that is, before the rotations are
        performed) the screen horizontal axis is x, screen vertical
        axis is y, and the axis perpendicular to the screen is z.  The
        first rotation applied is <rot_x> around the x axis.  The sec-
        ond rotation applied is <rot_z> around the new z axis.

        Command sseett vviieeww mmaapp is used to represent the drawing as a map.
        It can be used for ccoonnttoouurr plots, or for color ppmm33dd maps. In
        the latter, take care that you properly use zzrraannggee and ccbbrraannggee
        for input data point filtering and color range scaling, respec-
        tively.

        <rot_x> is bounded to the [0:180] range with a default of 60
        degrees, while <rot_z> is bounded to the [0:360] range with a
        default of 30 degrees.  <scale> controls the scaling of the
        entire sspplloott, while <scale_z> scales the z axis only.  Both
        scales default to 1.0.

        Examples:
              set view 60, 30, 1, 1
              set view ,,0.5

        The first sets all the four default values.  The second changes
        only scale, to 0.5.

        See also sseett ttiiccsslleevveell.



        3388..7722..  VVrraannggee


        The sseett uurraannggee and sseett vvrraannggee commands set the parametric
        ranges used to compute x, y, and z values when in sspplloott para-
        metric mode.  Please see sseett xxrraannggee for details.



        3388..7733..  XX22ddaattaa


        The sseett xx22ddaattaa command sets data on the x2 (top) axis to time-
        series (dates/times).  Please see sseett xxddaattaa.



        3388..7744..  XX22ddttiiccss


        The sseett xx22ddttiiccss command changes tics on the x2 (top) axis to
        days of the week.  Please see sseett xxddttiiccss for details.












   GNUPLOT 4.0                                                      225


        3388..7755..  XX22llaabbeell


        The sseett xx22llaabbeell command sets the label for the x2 (top) axis.
        Please see sseett xxllaabbeell.



        3388..7766..  XX22mmttiiccss


        The sseett xx22mmttiiccss command changes tics on the x2 (top) axis to
        months of the year.  Please see sseett xxmmttiiccss for details.



        3388..7777..  XX22rraannggee


        The sseett xx22rraannggee command sets the horizontal range that will be
        displayed on the x2 (top) axis.  Please see sseett xxrraannggee for
        details.



        3388..7788..  XX22ttiiccss


        The sseett xx22ttiiccss command controls major (labelled) tics on the x2
        (top) axis.  Please see sseett xxttiiccss for details.



        3388..7799..  XX22zzeerrooaaxxiiss


        The sseett xx22zzeerrooaaxxiiss command draws a line at the origin of the x2
        (top) axis (y2 = 0).  For details, please see sseett zzeerrooaaxxiiss.



        3388..8800..  XXddaattaa


        This command sets the datatype on the x axis to time/date.  A
        similar command does the same thing for each of the other axes.

        Syntax:
              set xdata {time}
              show xdata

        The same syntax applies to yyddaattaa, zzddaattaa, xx22ddaattaa, yy22ddaattaa and
        ccbbddaattaa.










   GNUPLOT 4.0                                                      226


        The ttiimmee option signals that the datatype is indeed time/date.
        If the option is not specified, the datatype reverts to normal.

        See sseett ttiimmeeffmmtt to tell gnuplot how to read date or time data.
        The time/date is converted to seconds from start of the cen-
        tury.  There is currently only one timefmt, which implies that
        all the time/date columns must conform to this format.  Speci-
        fication of ranges should be supplied as quoted strings accord-
        ing to this format to avoid interpretation of the time/date as
        an expression.

        The function 'strftime' (type "man strftime" on unix to look it
        up) is used to print tic-mark labels.  ggnnuupplloott tries to figure
        out a reasonable format for this  unless the sseett ffoorrmmaatt xx
        ""ssttrriinngg"" has supplied something that does not look like a deci-
        mal format (more than one '%' or neither %f nor %g).

        See also TTiimmee//ddaattee for more information.



        3388..8811..  XXddttiiccss


        The sseett xxddttiiccss commands converts the x-axis tic marks to days
        of the week where 0=Sun and 6=Sat.  Overflows are converted
        modulo 7 to dates.  sseett nnooxxddttiiccss returns the labels to their
        default values.  Similar commands do the same things for the
        other axes.

        Syntax:
              set xdtics
              unset xdtics
              show xdtics

        The same syntax applies to yyddttiiccss, zzddttiiccss, xx22ddttiiccss, yy22ddttiiccss and
        ccbbddttiiccss.

        See also the sseett ffoorrmmaatt command.



        3388..8822..  XXllaabbeell


        The sseett xxllaabbeell command sets the x axis label.  Similar commands
        set labels on the other axes.

        Syntax:
              set xlabel {"<label>"} {<xoff>}{,<yoff>} {font
        "<font>{,<size>}"}
                         {{textcolor | tc} {lt <line_type> | default}}
              show xlabel










   GNUPLOT 4.0                                                      227


        The same syntax applies to xx22llaabbeell, yyllaabbeell, yy22llaabbeell, zzllaabbeell and
        ccbbllaabbeell.

        Specifying the constants <xoff> or <yoff> as optional offsets
        for a label will move it <xoff> or <yoff> character widths or
        heights.  For example, " sseett xxllaabbeell --11" will change only the x
        offset of the xlabel, moving the label roughly one character
        width to the left.   The size of a character depends on both
        the font and the terminal.

        <font> is used to specify the font in which the label is writ-
        ten; the units of the font <size> depend upon which terminal is
        used.

        tteexxttccoolloorr lltt <<nn>> sets the text color to that of line type <n>.

        To clear a label, put no options on the command line, e.g.,
        "sseett yy22llaabbeell".

        The default positions of the axis labels are as follows:

        xlabel:  The x-axis label is centered below the bottom axis.

        ylabel:  The position of the y-axis label depends on the termi-
        nal, and can be one of the following three positions:

        1. Horizontal text flushed left at the top left of the plot.
        Terminals that cannot rotate text will probably use this
        method.  If sseett xx22ttiiccss is also in use, the ylabel may overwrite
        the left-most x2tic label.  This may be remedied by adjusting
        the ylabel position or the left margin.

        2. Vertical text centered vertically at the left of the plot.
        Terminals that can rotate text will probably use this method.

        3. Horizontal text centered vertically at the left of the plot.
        The EEPIC, LaTeX and TPIC drivers use this method.  The EEPIC
        driver will produce a stack of characters so as not to over-
        write the plot. With other drivers (such as LaTeX and TPIC),
        the user probably has to insert line breaks using \\ to prevent
        the ylabel from overwriting the plot.

        zlabel: The z-axis label is centered along the z axis and
        placed in the space above the grid level.

        cblabel: The color box axis label is centered along the box and
        placed below or right according to horizontal or vertical color
        box gradient.

        y2label: The y2-axis label is placed to the right of the y2
        axis.  The position is terminal-dependent in the same manner as
        is the y-axis label.











   GNUPLOT 4.0                                                      228


        x2label: The x2-axis label is placed above the top axis but
        below the plot title.  It is also possible to create an x2-axis
        label by using new-line characters to make a multi-line plot
        title, e.g.,

              set title "This is the title\n\nThis is the x2label"

        Note that double quotes must be used.  The same font will be
        used for both lines, of course.

        If you are not satisfied with the default position of an axis
        label, use sseett llaabbeell instead--that command gives you much more
        control over where text is placed.

        Please see ssyynnttaaxx for further information about backslash pro-
        cessing and the difference between single- and double-quoted
        strings.



        3388..8833..  XXmmttiiccss


        The sseett xxmmttiiccss command converts the x-axis tic marks to months
        of the year where 1=Jan and 12=Dec.  Overflows are converted
        modulo 12 to months.  The tics are returned to their default
        labels by uunnsseett xxmmttiiccss.  Similar commands perform the same
        duties for the other axes.

        Syntax:
              set xmtics
              unset xmtics
              show xmtics

        The same syntax applies to xx22mmttiiccss, yymmttiiccss, yy22mmttiiccss, zzmmttiiccss and
        ccbbmmttiiccss.

        See also the sseett ffoorrmmaatt command.



        3388..8844..  XXrraannggee


        The sseett xxrraannggee command sets the horizontal range that will be
        displayed.  A similar command exists for each of the other
        axes, as well as for the polar radius r and the parametric
        variables t, u, and v.

        Syntax:
              set xrange { [{{<min>}:{<max>}}] {{no}reverse}
        {{no}writeback} }
                         | restore










   GNUPLOT 4.0                                                      229


              show xrange

        where <min> and <max> terms are constants, expressions or an
        asterisk to set autoscaling.  If the data are time/date, you
        must give the range as a quoted string according to the sseett
        ttiimmeeffmmtt format.  Any value omitted will not be changed.

        The same syntax applies to yyrraannggee, zzrraannggee, xx22rraannggee, yy22rraannggee,
        ccbbrraannggee, rrrraannggee, ttrraannggee, uurraannggee and vvrraannggee.

        The rreevveerrssee option reverses the direction of the axis, e.g.,
        sseett xxrraannggee [[00::11]] rreevveerrssee will produce an axis with 1 on the
        left and 0 on the right.  This is identical to the axis pro-
        duced by sseett xxrraannggee [[11::00]], of course.  rreevveerrssee is intended pri-
        marily for use with aauuttoossccaallee.

        The wwrriitteebbaacckk option essentially saves the range found by
        aauuttoossccaallee in the buffers that would be filled by sseett xxrraannggee.
        This is useful if you wish to plot several functions together
        but have the range determined by only some of them.  The wwrriittee--
        bbaacckk operation is performed during the pplloott execution, so it
        must be specified before that command.  To restore, the last
        saved horizontal range use sseett xxrraannggee rreessttoorree.  For example,

              set xrange [-10:10]
              set yrange [] writeback
              plot sin(x)
              set yrange restore
              replot x/2

        results in a yrange of [-1:1] as found only from the range of
        sin(x); the [-5:5] range of x/2 is ignored.  Executing sshhooww
        yyrraannggee after each command in the above example should help you
        understand what is going on.

        In 2-d, xxrraannggee and yyrraannggee determine the extent of the axes,
        ttrraannggee determines the range of the parametric variable in para-
        metric mode or the range of the angle in polar mode.  Similarly
        in parametric 3-d, xxrraannggee, yyrraannggee, and zzrraannggee govern the axes
        and uurraannggee and vvrraannggee govern the parametric variables.

        In polar mode, rrrraannggee determines the radial range plotted.
        <rmin> acts as an additive constant to the radius, whereas
        <rmax> acts as a clip to the radius---no point with radius
        greater than <rmax> will be plotted.  xxrraannggee and yyrraannggee are
        affected---the ranges can be set as if the graph was of
        r(t)-rmin, with rmin added to all the labels.

        Any range may be partially or totally autoscaled, although it
        may not make sense to autoscale a parametric variable unless it
        is plotted with data.

        Ranges may also be specified on the pplloott command line.  A range










   GNUPLOT 4.0                                                      230


        given on the plot line will be used for that single pplloott com-
        mand; a range given by a sseett command will be used for all sub-
        sequent plots that do not specify their own ranges.  The same
        holds true for sspplloott.

        Examples:

        To set the xrange to the default:
              set xrange [-10:10]

        To set the yrange to increase downwards:
              set yrange [10:-10]

        To change zmax to 10 without affecting zmin (which may still be
        autoscaled):
              set zrange [:10]

        To autoscale xmin while leaving xmax unchanged:
              set xrange [*:]



        3388..8855..  XXttiiccss


        Fine control of the major (labelled) tics on the x axis is pos-
        sible with the sseett xxttiiccss command.  The tics may be turned off
        with the uunnsseett xxttiiccss command, and may be turned on (the default
        state) with sseett xxttiiccss.  Similar commands control the major tics
        on the y, z, x2 and y2 axes.

        Syntax:
              set xtics {axis | border} {{no}mirror} {{no}rotate {by
        <ang>}}
                        {  autofreq
                         | <incr>
                         | <start>, <incr> {,<end>}
                         | ({"<label>"} <pos> {<level>}
        {,{"<label>"}...) }
                        { font "name{,<size>}" }
                        { textcolor <colorspec> }
              unset xtics
              show xtics

        The same syntax applies to yyttiiccss, zzttiiccss, xx22ttiiccss, yy22ttiiccss and
        ccbbttiiccss.

        aaxxiiss or bboorrddeerr tells ggnnuupplloott to put the tics (both the tics
        themselves and the accompanying labels) along the axis or the
        border, respectively.  If the axis is very close to the border,
        the aaxxiiss option will move the tic labels to outside the border.
        The relevant margin settings will usually be sized badly by the
        automatic layout algorithm in this case.










   GNUPLOT 4.0                                                      231


        mmiirrrroorr tells ggnnuupplloott to put unlabelled tics at the same posi-
        tions on the opposite border.  nnoommiirrrroorr does what you think it
        does.

        rroottaattee asks ggnnuupplloott to rotate the text through 90 degrees,
        which will be done if the terminal driver in use supports text
        rotation.  nnoorroottaattee cancels this. rroottaattee bbyy <<aanngg>> asks for
        rotation by <ang> degrees, supported by some terminal types.

        The defaults are bboorrddeerr mmiirrrroorr nnoorroottaattee for tics on the x and y
        axes, and bboorrddeerr nnoommiirrrroorr nnoorroottaattee for tics on the x2 and y2
        axes.  For the z axis, the {{aaxxiiss || bboorrddeerr}} option is not avail-
        able and the default is nnoommiirrrroorr.  If you do want to mirror the
        z-axis tics, you might want to create a bit more room for them
        with sseett bboorrddeerr.

        sseett xxttiiccss with no options restores the default border or axis
        if xtics are being displayed;  otherwise it has no effect.  Any
        previously specified tic frequency or position {and labels} are
        retained.

        Positions of the tics are calculated automatically by default
        or if the aauuttooffrreeqq option is given; otherwise they may be spec-
        ified in either of two forms:

        The implicit <start>, <incr>, <end> form specifies that a
        series of tics will be plotted on the axis between the values
        <start> and <end> with an increment of <incr>.  If <end> is not
        given, it is assumed to be infinity.  The increment may be neg-
        ative.  If neither <start> nor <end> is given, <start> is
        assumed to be negative infinity, <end> is assumed to be posi-
        tive infinity, and the tics will be drawn at integral multiples
        of <incr>.  If the axis is logarithmic, the increment will be
        used as a multiplicative factor.

        The sseett ggrriidd options 'front', 'back' and 'layerdefault' affect
        the drawing order of the xtics, too.

        Examples:

        Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
              set xtics 0,.5,10

        Make tics at ..., -10, -5, 0, 5, 10, ...
              set xtics 5

        Make tics at 1, 100, 1e4, 1e6, 1e8.
              set logscale x; set xtics 1,100,1e8

        The explicit ("<label>" <pos> <level>, ...) form allows arbi-
        trary tic positions or non-numeric tic labels.  In this form,
        the tics do not need to be listed in numerical order.  Each tic
        has a position, optionally with a label.  Note that the label










   GNUPLOT 4.0                                                      232


        is a string enclosed by quotes.  It may be a constant string,
        such as "hello", may contain formatting information for con-
        verting the position into its label, such as "%3f clients", or
        may be empty, "".  See sseett ffoorrmmaatt for more information.  If no
        string is given, the default label (numerical) is used.

        An explicit tic mark has a third parameter, the "level".  The
        default is level 0, a major tic.  A level of 1 generates a
        minor tic.  If the level is specified, then the label must also
        be supplied.

        Examples:
              set xtics ("low" 0, "medium" 50, "high" 100)
              set xtics (1,2,4,8,16,32,64,128,256,512,1024)
              set ytics ("bottom" 0, "" 10, "top" 20)
              set ytics ("bottom" 0, "" 10 1, "top" 20)

        In the second example, all tics are labelled.  In the third,
        only the end tics are labelled.  In the fourth, the unlabeled
        tic is a minor tic.

        However they are specified, tics will only be plotted when in
        range.

        Format (or omission) of the tic labels is controlled by sseett
        ffoorrmmaatt, unless the explicit text of a labels is included in the
        sseett xxttiiccss ((<label>)) form.

        Minor (unlabelled) tics can be added by the sseett mmxxttiiccss command.

        In case of timeseries data, position values must be given as
        quoted dates or times according to the format ttiimmeeffmmtt.  If the
        <start>, <incr>, <end> form is used, <start> and <end> must be
        given according to ttiimmeeffmmtt, but <incr> must be in seconds.
        Times will be written out according to the format given on sseett
        ffoorrmmaatt, however.

        Examples:
              set xdata time
              set timefmt "%d/%m"
              set format x "%b %d"
              set xrange ["01/12":"06/12"]
              set xtics "01/12", 172800, "05/12"

              set xdata time
              set timefmt "%d/%m"
              set format x "%b %d"
              set xrange ["01/12":"06/12"]
              set xtics ("01/12", "" "03/12", "05/12")
        Both of these will produce tics "Dec 1", "Dec 3", and "Dec 5",
        but in the second example the tic at "Dec 3" will be unla-
        belled.











   GNUPLOT 4.0                                                      233


        3388..8866..  XXzzeerrooaaxxiiss


        The sseett xxzzeerrooaaxxiiss command draws a line at y = 0.  For details,
        please see sseett zzeerrooaaxxiiss.



        3388..8877..  YY22ddaattaa


        The sseett yy22ddaattaa command sets y2 (right-hand) axis data to time-
        series (dates/times).  Please see sseett xxddaattaa.



        3388..8888..  YY22ddttiiccss


        The sseett yy22ddttiiccss command changes tics on the y2 (right-hand)
        axis to days of the week.  Please see sseett xxddttiiccss for details.



        3388..8899..  YY22llaabbeell


        The sseett yy22llaabbeell command sets the label for the y2 (right-hand)
        axis.  Please see sseett xxllaabbeell.



        3388..9900..  YY22mmttiiccss


        The sseett yy22mmttiiccss command changes tics on the y2 (right-hand)
        axis to months of the year.  Please see sseett xxmmttiiccss for details.



        3388..9911..  YY22rraannggee


        The sseett yy22rraannggee command sets the vertical range that will be
        displayed on the y2 (right-hand) axis.  Please see sseett xxrraannggee
        for details.



        3388..9922..  YY22ttiiccss













   GNUPLOT 4.0                                                      234


        The sseett yy22ttiiccss command controls major (labelled) tics on the y2
        (right-hand) axis.  Please see sseett xxttiiccss for details.



        3388..9933..  YY22zzeerrooaaxxiiss


        The sseett yy22zzeerrooaaxxiiss command draws a line at the origin of the y2
        (right-hand) axis (x2 = 0).  For details, please see sseett
        zzeerrooaaxxiiss.



        3388..9944..  YYddaattaa


        The sseett yyddaattaa commands sets y-axis data to timeseries
        (dates/times).  Please see sseett xxddaattaa.



        3388..9955..  YYddttiiccss


        The sseett yyddttiiccss command changes tics on the y axis to days of
        the week.  Please see sseett xxddttiiccss for details.



        3388..9966..  YYllaabbeell


        This command sets the label for the y axis.  Please see sseett
        xxllaabbeell.



        3388..9977..  YYmmttiiccss


        The sseett yymmttiiccss command changes tics on the y axis to months of
        the year.  Please see sseett xxmmttiiccss for details.



        3388..9988..  YYrraannggee


        The sseett yyrraannggee command sets the vertical range that will be
        displayed on the y axis.  Please see sseett xxrraannggee for details.












   GNUPLOT 4.0                                                      235


        3388..9999..  YYttiiccss


        The sseett yyttiiccss command controls major (labelled) tics on the y
        axis.  Please see sseett xxttiiccss for details.



        3388..110000..  YYzzeerrooaaxxiiss


        The sseett yyzzeerrooaaxxiiss command draws a line at x = 0.  For details,
        please see sseett zzeerrooaaxxiiss.



        3388..110011..  ZZddaattaa


        The sseett zzddaattaa command sets zaxis data to timeseries
        (dates/times).  Please see sseett xxddaattaa.



        3388..110022..  ZZddttiiccss


        The sseett zzddttiiccss command changes tics on the z axis to days of
        the week.  Please see sseett xxddttiiccss for details.



        3388..110033..  CCbbddaattaa


        Set color box axis data to timeseries (dates/times).  Please
        see sseett xxddaattaa.



        3388..110044..  CCbbddttiiccss


        The sseett ccbbddttiiccss command changes tics on the color box axis to
        days of the week. Please see sseett xxddttiiccss for details.



        3388..110055..  ZZeerroo


        The zzeerroo value is the default threshold for values approaching
        0.0.










   GNUPLOT 4.0                                                      236


        Syntax:
              set zero <expression>
              show zero

        ggnnuupplloott will not plot a point if its imaginary part is greater
        in magnitude than the zzeerroo threshold.  This threshold is also
        used in various other parts of ggnnuupplloott as a (crude) numerical-
        error threshold.  The default zzeerroo value is 1e-8.  zzeerroo values
        larger than 1e-3 (the reciprocal of the number of pixels in a
        typical bitmap display) should probably be avoided, but it is
        not unreasonable to set zzeerroo to 0.0.



        3388..110066..  ZZeerrooaaxxiiss


        The x axis may be drawn by sseett xxzzeerrooaaxxiiss and removed by uunnsseett
        xxzzeerrooaaxxiiss.  Similar commands behave similarly for the y, x2,
        and y2 axes.

        Syntax:
              set {x|x2|y|y2|}zeroaxis { {linestyle | ls <line_style>}
                                         | { linetype | lt <line_type>}
                                           { linewidth | lw
        <line_width>}}
              unset {x|x2|y|y2|}zeroaxis
              show {x|y|}zeroaxis


        By default, these options are off.  The selected zero axis is
        drawn with a line of type <line_type> and width <line_width>
        (if supported by the terminal driver currently in use), or a
        user-defined style <line_style>.

        If no linetype is specified, any zero axes selected will be
        drawn using the axis linetype (linetype 0).

        sseett zzeerrooaaxxiiss is equivalent to sseett xxzzeerrooaaxxiiss;; sseett yyzzeerrooaaxxiiss.
        sseett nnoozzeerrooaaxxiiss is equivalent to uunnsseett xxzzeerrooaaxxiiss;; uunnsseett yyzzee--
        rrooaaxxiiss.

        Examples:

        To simply have the y=0 axis drawn visibly:

               set xzeroaxis

        If you want a thick line in a different color or pattern,
        instead:

               set xzeroaxis linetype 3 linewidth 2.5











   GNUPLOT 4.0                                                      237


        3388..110077..  ZZllaabbeell


        This command sets the label for the z axis.  Please see sseett
        xxllaabbeell.



        3388..110088..  ZZmmttiiccss


        The sseett zzmmttiiccss command changes tics on the z axis to months of
        the year.  Please see sseett xxmmttiiccss for details.



        3388..110099..  ZZrraannggee


        The sseett zzrraannggee command sets the range that will be displayed on
        the z axis.  The zrange is used only by sspplloott and is ignored by
        pplloott.  Please see sseett xxrraannggee for details.



        3388..111100..  ZZttiiccss


        The sseett zzttiiccss command controls major (labelled) tics on the z
        axis.  Please see sseett xxttiiccss for details.



        3388..111111..  CCbbllaabbeell


        This command sets the label for the color box axis.  Please see
        sseett xxllaabbeell.



        3388..111122..  CCbbmmttiiccss


        The sseett ccbbmmttiiccss command changes tics on the color box axis to
        months of the year. Please see sseett xxmmttiiccss for details.



        3388..111133..  CCbbrraannggee













   GNUPLOT 4.0                                                      238


        The sseett ccbbrraannggee command sets the range of z-values which are
        colored by ppmm33dd mode of sspplloott. If the cb-axis is autoscaled,
        then the ppmm33dd / ppaalleettttee range is taken from zzrraannggee.

        Please see sseett xxrraannggee for details on sseett ccbbrraannggee syntax.



        3388..111144..  CCbbttiiccss


        The sseett ccbbttiiccss command controls major (labelled) tics on the
        color box axis.  Please see sseett xxttiiccss for details.



   3399..  SShheellll


   The sshheellll command spawns an interactive shell.  To return to ggnnuu--
   pplloott, type llooggoouutt if using VMS, eexxiitt or the END-OF-FILE character if
   using Unix, eennddccllii if using AmigaOS, or eexxiitt if using MS-DOS or
   OS/2.

   There are two ways of spawning a shell command: using ssyysstteemm command
   or via !! ($ if using VMS). The former command takes a string as a
   parameter and thus it can be used anywhere among other gnuplot com-
   mands, while the latter syntax requires to be the only command on
   the line. Control will return immediately to ggnnuupplloott after this com-
   mand is executed.  For example, in AmigaOS, MS-DOS or OS/2,

         ! dir
   or
         system "dir"


   prints a directory listing and then returns to ggnnuupplloott.


   Other examples of the former syntax:
          system "date"; set time; plot "a.dat"
          print=1; if (print) replot; set out; system "lpr x.ps"

   On an Atari, the !! command first checks whether a shell is already
   loaded and uses it, if available.  This is practical if ggnnuupplloott is
   run from gguullaamm, for example.



   4400..  SSpplloott













   GNUPLOT 4.0                                                      239


   sspplloott is the command for drawing 3-d plots (well, actually projec-
   tions on a 2-d surface, but you knew that).  It can create a plot
   from functions or a data file in a manner very similar to the pplloott
   command.

   See pplloott for features common to the pplloott command; only differences
   are discussed in detail here.  Note specifically that the bbiinnaarryy and
   mmaattrriixx options (discussed under "datafile-modifiers") are not avail-
   able for pplloott, and pplloott's aaxxeess option is not available for sspplloott.

   Syntax:
         splot {<ranges>}
               <function> | "<datafile>" {datafile-modifiers}}
               {<title-spec>} {with <style>}
               {, {definitions,} <function> ...}

   where either a <function> or the name of a data file enclosed in
   quotes is supplied.  The function can be a mathematical expression,
   or a triple of mathematical expressions in parametric mode.

   By default sspplloott draws the xy plane completely below the plotted
   data.  The offset between the lowest ztic and the xy plane can be
   changed by sseett ttiiccsslleevveell.  The orientation of a sspplloott projection is
   controlled by sseett vviieeww.  See sseett vviieeww and sseett ttiiccsslleevveell for more
   information.

   The syntax for setting ranges on the sspplloott command is the same as
   for pplloott.  In non-parametric mode, the order in which ranges must be
   given is xxrraannggee, yyrraannggee, and zzrraannggee.  In parametric mode, the order
   is uurraannggee, vvrraannggee, xxrraannggee, yyrraannggee, and zzrraannggee.

   The ttiittllee option is the same as in pplloott.  The operation of wwiitthh is
   also the same as in pplloott, except that the plotting styles available
   to sspplloott are limited to lliinneess, ppooiinnttss, lliinneessppooiinnttss, ddoottss, and
   iimmppuullsseess;  the error-bar capabilities of pplloott are not available for
   sspplloott.

   The ddaattaaffiillee options have more differences.

   See also sshhooww pplloott.




        4400..11..  DDaattaa--ffiillee


        As for pplloott, discrete data contained in a file can be displayed
        by specifying the name of the data file, enclosed in quotes,
        on the sspplloott command line.

        Syntax:
              splot '<file_name>' {binary | matrix}










   GNUPLOT 4.0                                                      240


                                  {index <index list>}
                                  {every <every list>}
                                  {using <using list>}

        The special filenames """" and ""--"" are permitted, as in pplloott.

        In brief, bbiinnaarryy and mmaattrriixx indicate that the data are in a
        special form, iinnddeexx selects which data sets in a multi-data-set
        file are to be plotted, eevveerryy specifies which datalines (sub-
        sets) within a single data set are to be plotted, and uussiinngg
        determines how the columns within a single record are to be
        interpreted.

        The options iinnddeexx and eevveerryy behave the same way as with pplloott;
        uussiinngg does so also, except that the uussiinngg list must provide
        three entries instead of two.

        The pplloott options tthhrruu and ssmmooootthh are not available for sspplloott,
        but ccnnttrrppaarraamm and ddggrriidd33dd provide limited smoothing capabili-
        ties.

        Data file organization is essentially the same as for pplloott,
        except that each point is an (x,y,z) triple.  If only a single
        value is provided, it will be used for z, the datablock number
        will be used for y, and the index of the data point in the dat-
        ablock will be used for x.  If two or four values are provided,
        ggnnuupplloott uses the last value for calculating the color in pm3d
        plots.  Three values are interpreted as an (x,y,z) triple.
        Additional values are generally used as errors, which can be
        used by ffiitt.

        Single blank records separate datablocks in a sspplloott datafile;
        sspplloott treats datablocks as the equivalent of function y-iso-
        lines.  No line will join points separated by a blank record.
        If all datablocks contain the same number of points, ggnnuupplloott
        will draw cross-isolines between datablocks, connecting corre-
        sponding points.  This is termed "grid data", and is required
        for drawing a surface, for contouring (sseett ccoonnttoouurr) and hidden-
        line removal (sseett hhiiddddeenn33dd). See also sspplloott ggrriidd__ddaattaa.

        It is no longer necessary to specify ppaarraammeettrriicc mode for three-
        column ssppllootts.




             4400..11..11..  BBiinnaarryy


             sspplloott can read binary files written with a specific format
             (and on a system with a compatible binary file representa-
             tion.)











   GNUPLOT 4.0                                                      241


             In previous versions, ggnnuupplloott dynamically detected binary
             data files.  It is now necessary to specify the keyword
             bbiinnaarryy directly after the filename.

             Single precision floats are stored in a binary file as
             follows:

                   <N+1>  <y0>   <y1>   <y2>  ...  <yN>
                    <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
                    <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
                     :      :      :      :   ...    :

             which are converted into triplets:
                   <x0> <y0> <z0,0>
                   <x0> <y1> <z0,1>
                   <x0> <y2> <z0,2>
                    :    :     :
                   <x0> <yN> <z0,N>

                   <x1> <y0> <z1,0>
                   <x1> <y1> <z1,1>
                    :    :     :

             These triplets are then converted into ggnnuupplloott iso-curves
             and then ggnnuupplloott proceeds in the usual manner to do the
             rest of the plotting.

             A collection of matrix and vector manipulation routines
             (in C) is provided in bbiinnaarryy..cc.  The routine to write
             binary data is

                   int
             fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,col-
             umn_title)

             An example of using these routines is provided in the file
             bbff__tteesstt..cc, which generates binary files for the demo file
             ddeemmoo//bbiinnaarryy..ddeemm.

             The iinnddeexx keyword is not supported, since the file format
             allows only one surface per file.  The eevveerryy and uussiinngg
             filters are supported.  uussiinngg operates as if the data were
             read in the above triplet form.  See also Binary File
             Splot Demo.



             4400..11..22..  EExxaammppllee ddaattaaffiillee


             A simple example of plotting a 3-d data file is

                   splot 'datafile.dat'










   GNUPLOT 4.0                                                      242


             where the file "datafile.dat" might contain:

                   # The valley of the Gnu.
                      0 0 10
                      0 1 10
                      0 2 10

                      1 0 10
                      1 1 5
                      1 2 10

                      2 0 10
                      2 1 1
                      2 2 10

                      3 0 10
                      3 1 0
                      3 2 10

             Note that "datafile.dat" defines a 4 by 3 grid ( 4 rows of
             3 points each ).  Rows (datablocks) are separated by blank
             records.

             Note also that the x value is held constant within each
             dataline.  If you instead keep y constant, and plot with
             hidden-line removal enabled, you will find that the sur-
             face is drawn 'inside-out'.

             Actually for grid data it is not necessary to keep the x
             values constant within a datablock, nor is it necessary to
             keep the same sequence of y values.  ggnnuupplloott requires only
             that the number of points be the same for each datablock.
             However since the surface mesh, from which contours are
             derived, connects sequentially corresponding points, the
             effect of an irregular grid on a surface plot is unpre-
             dictable and should be examined on a case-by-case basis.



             4400..11..33..  MMaattrriixx


             The mmaattrriixx flag indicates that the ASCII data are stored
             in matrix format.  The z-values are read in a row at a
             time, i. e.,
                   z11 z12 z13 z14 ...
                   z21 z22 z23 z24 ...
                   z31 z32 z33 z34 ...
             and so forth.  The row and column indices are used for the
             x- and y-values.

             A blank line or comment line ends the matrix, and starts a
             new surface mesh. You can select among the meshes inside a










   GNUPLOT 4.0                                                      243


             file by the iinnddeexx option to the sspplloott command, as usual.



        4400..22..  GGrriidd__ddaattaa


        The 3D routines are designed for points in a grid format, with
        one sample, datapoint, at each mesh intersection; the data-
        points may originate from either evaluating a function, see sseett
        iissoossaammpplleess, or reading a datafile, see sspplloott ddaattaaffiillee.  The
        term "isoline" is applied to the mesh lines for both functions
        and data.  Note that the mesh need not be rectangular in x and
        y, as it may be parameterized in u and v, see sseett iissoossaammpplleess.

        However, ggnnuupplloott does not require that format.  In the case of
        functions, 'samples' need not be equal to 'isosamples', i.e.,
        not every x-isoline sample need intersect a y-isoline. In the
        case of data files, if there are an equal number of scattered
        data points in each datablock, then "isolines" will connect the
        points in a datablock, and "cross-isolines" will connect the
        corresponding points in each datablock to generate a "surface".
        In either case, contour and hidden3d modes may give different
        plots than if the points were in the intended format.  Scat-
        tered data can be converted to a {different} grid format with
        sseett ddggrriidd33dd.

        The contour code tests for z intensity along a line between a
        point on a y-isoline and the corresponding point in the next y-
        isoline.  Thus a sspplloott contour of a surface with samples on the
        x-isolines that do not coincide with a y-isoline intersection
        will ignore such samples. Try:
               set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
               set style function lp
               set contour
               set isosamples 10,10; set samples 10,10;
               splot cos(x)*cos(y)
               set samples 4,10; replot
               set samples 10,4; replot




        4400..33..  SSpplloott__oovveerrvviieeww


        sspplloott can display a surface as a collection of points, or by
        connecting those points.  As with pplloott, the points may be read
        from a data file or result from evaluation of a function at
        specified intervals, see sseett iissoossaammpplleess.  The surface may be
        approximated by connecting the points with straight line seg-
        ments, see sseett ssuurrffaaccee, in which case the surface can be made
        opaque with sseett hhiiddddeenn33dd..  The orientation from which the 3d










   GNUPLOT 4.0                                                      244


        surface is viewed can be changed with sseett vviieeww.

        Additionally, for points in a grid format, sspplloott can interpo-
        late points having a common amplitude (see sseett ccoonnttoouurr) and can
        then connect those new points to display contour lines, either
        directly with straight-line segments or smoothed lines (see sseett
        ccnnttrrppaarraamm).  Functions are already evaluated in a grid format,
        determined by sseett iissoossaammpplleess and sseett ssaammpplleess, while file data
        must either be in a grid format, as described in ddaattaa--ffiillee, or
        be used to generate a grid (see sseett ddggrriidd33dd).

        Contour lines may be displayed either on the surface or pro-
        jected onto the base.  The base projections of the contour
        lines may be written to a file, and then read with pplloott, to
        take advantage of pplloott's additional formatting capabilities.



   4411..  SSyysstteemm


   ssyysstteemm spawns shell to execute a command. Please type hheellpp sshheellll for
   more details.



   4422..  TTeesstt


   This command graphically tests or presents terminal and palette
   capabilities.

   Syntax:
         test {terminal | palette [rgb|rbg|grb|gbr|brg|bgr]}

   tteesstt or tteesstt tteerrmmiinnaall creates a display of line and point styles and
   other useful things appropriate for and supported by the tteerrmmiinnaall
   you are just using.

   tteesstt ppaalleettttee draws graphically profiles R(z),G(z),B(z), where
   0<=z<=1, as calculated by the current color ppaalleettttee. In other words,
   it is a beautiful plot you would have to do yourself with the result
   of sshhooww ppaalleettttee ppaalleettttee 225566 ffllooaatt.  The optional parameter, a permu-
   tation of letters rgb, determines the sequence of r,g,b profiles
   drawn one after the other --- try this yourself for sseett ppaalleettttee
   ggrraayy. The default sequence is rgb.



   4433..  UUnnsseett













   GNUPLOT 4.0                                                      245


   Options set using the sseett command may be returned to their default
   state by issuing the corresponding uunnsseett command.

   Example:
         set xtics mirror rotate by -45 0,10,100
         ...
         unset xtics




   4444..  UUppddaattee


   This command writes the current values of the fit parameters into
   the given file, formatted as an initial-value file (as described in
   the ffiittsection).  This is useful for saving the current values for
   later use or for restarting a converged or stopped fit.

   Syntax:
         update <filename> {<filename>}

   If a second filename is supplied, the updated values are written to
   this file, and the original parameter file is left unmodified.

   Otherwise, if the file already exists, ggnnuupplloott first renames it by
   appending ..oolldd and then opens a new file.  That is, "uuppddaattee ''ffrreedd''"
   behaves the same as "!!rreennaammee ffrreedd ffrreedd..oolldd;; uuppddaattee ''ffrreedd..oolldd''
   ''ffrreedd''".  [On DOS and other systems that use the twelve-character
   "filename.ext" naming convention, "ext" will be "oolldd" and "filename"
   will be related (hopefully recognizably) to the initial name.
   Renaming is not done at all on VMS systems, since they use file-ver-
   sioning.]

   Please see ffiitt for more information.




   4455..  GGrraapphhiiccaall UUsseerr IInntteerrffaacceess


   Several graphical user interfaces have been written for ggnnuupplloott and
   one for win32 is included in this distribution.  In addition, there
   is a Macintosh interface at
            ftp://ftp.ee.gatech.edu/pub/mac/gnuplot


   Also several X11 interfaces exist.  One of them is called xgfe. It
   uses the Qt library and can be found on
            http://www.flash.net/~dmishee/xgfe/xgfe.html

   In addition three Tcl/Tk located at the usual Tcl/Tk repositories










   GNUPLOT 4.0                                                      246


   exist.

   Bruce Ravel (ravel@phys.washington.edu) has written a new version of
   gnuplot-mode for GNU emacs and XEmacs. This version is based on the
   gnuplot.el file by Gershon Elber.  While the gnuplot CVS repository
   has its own copy the most recent version of this package is avail-
   able from
             http://feff.phys.washington.edu/~ravel/software/gnuplot-
   mode/





   4466..  BBuuggss


   Floating point exceptions (floating point number too large/small,
   divide by zero, etc.) may occasionally be generated by user defined
   functions.  Some of the demos in particular may cause numbers to
   exceed the floating point range.  Whether the system ignores such
   exceptions (in which case ggnnuupplloott labels the corresponding point as
   undefined) or aborts ggnnuupplloott depends on the compiler/runtime envi-
   ronment.

   The bessel functions do not work for complex arguments.

   The gamma function does not work for complex arguments.

   As of ggnnuupplloott version 3.7, all development has been done using ANSI
   C.  With current operating system, compiler, and library releases,
   the OS specific bugs documented in release 3.5, now relegated to
   oolldd__bbuuggss, may no longer be relevant.

   Bugs reported since the current release as well as older ones may be
   located via the official distribution site:
             http://www.gnuplot.info

   Please e-mail any bugs to bug-gnuplot mailing list (see SSeeeekkiinngg--
   aassssiissttaannccee).




   4477..  OOlldd__bbuuggss


   There is a bug in the stdio library for old Sun operating systems
   (SunOS Sys4-3.2).  The "%g" format for 'printf' sometimes incor-
   rectly prints numbers (e.g., 200000.0 as "2").  Thus, tic mark
   labels may be incorrect on a Sun4 version of ggnnuupplloott.  A work-around
   is to rescale the data or use the sseett ffoorrmmaatt command to change the
   tic mark format to "%7.0f" or some other appropriate format.  This










   GNUPLOT 4.0                                                      247


   appears to have been fixed in SunOS 4.0.

   Another bug: On a Sun3 under SunOS 4.0, and on Sun4's under Sys4-3.2
   and SunOS 4.0, the 'sscanf' routine incorrectly parses "00 12" with
   the format "%f %f" and reads 0 and 0 instead of 0 and 12.  This
   affects data input.  If the data file contains x coordinates that
   are zero but are specified like '00', '000', etc, then you will read
   the wrong y values.  Check any data files or upgrade the SunOS.  It
   appears to have been fixed in SunOS 4.1.1.

   Suns appear to overflow when calculating exp(-x) for large x, so
   ggnnuupplloott gets an undefined result.  One work-around is to make a
   user-defined function like e(x) = x<-500 ? 0 : exp(x).  This affects
   plots of Gaussians (exp(-x*x)) in particular, since x*x grows quite
   rapidly.

   Microsoft C 5.1 has a nasty bug associated with the %g format for
   'printf'.  When any of the formats "%.2g", "%.1g", "%.0g", "%.g" are
   used, 'printf' will incorrectly print numbers in the range 1e-4 to
   1e-1.  Numbers that should be printed in the %e format are incor-
   rectly printed in the %f format, with the wrong number of zeros
   after the decimal point.  To work around this problem, use the %e or
   %f formats explicitly.

   ggnnuupplloott, when compiled with Microsoft C, did not work correctly on
   two VGA displays that were tested.  The CGA, EGA and VGA drivers
   should probably be rewritten to use the Microsoft C graphics
   library.  ggnnuupplloott compiled with Borland C++ uses the Turbo C graph-
   ics drivers and does work correctly with VGA displays.

   VAX/VMS 4.7 C compiler release 2.4 also has a poorly implemented %g
   format for 'printf'.  The numbers are printed numerically correct,
   but may not be in the requested format.  The K&R second edition says
   that for the %g format, %e is used if the exponent is less than -4
   or greater than or equal to the precision.  The VAX uses %e format
   if the exponent is less than -1.  The VAX appears to take no notice
   of the precision when deciding whether to use %e or %f for numbers
   less than 1.  To work around this problem, use the %e or %f formats
   explicitly.  From the VAX C 2.4 release notes: e,E,f,F,g,G  Result
   will always contain a decimal  point.  For g and G, trailing zeros
   will not be removed from the result.

   VAX/VMS 5.2 C compiler release 3.0 has a slightly better implemented
   %g format than release 2.4, but not much.  Trailing decimal points
   are now removed, but trailing zeros are still not removed from %g
   numbers in exponential format.

   The two preceding problems are actually in the libraries rather than
   in the compilers.  Thus the problems will occur whether ggnnuupplloott is
   built using either the DEC compiler or some other one (e.g. the lat-
   est gcc).

   ULTRIX X11R3 has a bug that causes the X11 driver to display "every










   GNUPLOT 4.0                                                      248


   other" graph.  The bug seems to be fixed in DEC's release of X11R4
   so newer releases of ULTRIX don't seem to have the problem.  Solu-
   tions for older sites include upgrading the X11 libraries (from DEC
   or direct from MIT) or defining ULTRIX_KLUDGE when compiling the
   x11.trm file.  Note that the kludge is not an ideal fix, however.

   The constant HUGE was incorrectly defined in the NeXT OS 2.0 operat-
   ing system.  HUGE should be set to 1e38 in plot.h. This error has
   been corrected in the 2.1 version of NeXT OS.

   Some older models of HP plotters do not have a page eject command
   'PG'.  The current HPGL driver uses this command in HPGL_reset.
   This may need to be removed for these plotters.  The current PCL5
   driver uses HPGL/2 for text as well as graphics.  This should be
   modified to use scalable PCL fonts.

   On the Atari version, it is not possible to send output directly to
   the printer (using //ddeevv//llpp as output file), since CRs are added to
   LFs in binary output.  As a work-around, write the output to a file
   and copy it to the printer afterwards using a shell command.

   On AIX 4, the literal 'NaNq' in a datafile causes the special inter-
   nal value 'not-a-number' to be stored, rather than setting an inter-
   nal 'undefined' flag.  A workaround is to use sseett ddaattaaffiillee mmiissssiinngg
   ''NNaaNNqq''.






































   GNUPLOT 4.0                                                        i



                            TTaabbllee ooff CCoonntteennttss


   Gnuplot  . . . . . . . . . . . . . . . . . . . . . . . . . . . .   1
   Copyright  . . . . . . . . . . . . . . . . . . . . . . . . . . .   1
   Introduction . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   Seeking-assistance . . . . . . . . . . . . . . . . . . . . . . .   3
   What is New in Version 4.0 . . . . . . . . . . . . . . . . . . .   4
   Mouse and hotkey support in interactive terminals  . . . . . . .   4
   New terminal features  . . . . . . . . . . . . . . . . . . . . .   5
   New plot style `pm3d`  . . . . . . . . . . . . . . . . . . . . .   5
   New plot style `filledcurves`  . . . . . . . . . . . . . . . . .   6
   Filled boxes . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   New plot option smooth frequency . . . . . . . . . . . . . . . .   6
   Improved text options  . . . . . . . . . . . . . . . . . . . . .   6
   More text encodings  . . . . . . . . . . . . . . . . . . . . . .   7
   Arrows . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Data file format . . . . . . . . . . . . . . . . . . . . . . . .   7
   Other changes and additions  . . . . . . . . . . . . . . . . . .   7
   Accompanying documentation . . . . . . . . . . . . . . . . . . .   8
   Batch/Interactive Operation  . . . . . . . . . . . . . . . . . .   9
   Command-line-editing . . . . . . . . . . . . . . . . . . . . . .   9
   Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Coordinates  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Environment  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Expressions  . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   Functions  . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
   Random number generator  . . . . . . . . . . . . . . . . . . . .  16
   Operators  . . . . . . . . . . . . . . . . . . . . . . . . . . .  16
   Unary  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  17
   Binary . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  17
   Ternary  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18
   User-defined . . . . . . . . . . . . . . . . . . . . . . . . . .  19
   Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20
   Mouse input  . . . . . . . . . . . . . . . . . . . . . . . . . .  21
   Bind . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  21
   Mouse_variables  . . . . . . . . . . . . . . . . . . . . . . . .  23
   Plotting . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23
   Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
   Substitution . . . . . . . . . . . . . . . . . . . . . . . . . .  24
   Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25
   Time/Date data . . . . . . . . . . . . . . . . . . . . . . . . .  26
   Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
   Cd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
   Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
   Clear  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  29
   Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  29
   Fit  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
   Adjustable parameters  . . . . . . . . . . . . . . . . . . . . .  31
   Short introduction . . . . . . . . . . . . . . . . . . . . . . .  32
   Error estimates  . . . . . . . . . . . . . . . . . . . . . . . .  33
   Statistical overview . . . . . . . . . . . . . . . . . . . . . .  34










   GNUPLOT 4.0                                                       ii


   Practical guidelines . . . . . . . . . . . . . . . . . . . . . .  35
   Fit controlling  . . . . . . . . . . . . . . . . . . . . . . . .  37
   Control variables  . . . . . . . . . . . . . . . . . . . . . . .  37
   Environment variables  . . . . . . . . . . . . . . . . . . . . .  38
   Multi-branch . . . . . . . . . . . . . . . . . . . . . . . . . .  38
   Starting values  . . . . . . . . . . . . . . . . . . . . . . . .  39
   Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
   Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
   History  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
   If . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
   Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
   Pause  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
   Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
   Data-file  . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
   Every  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
   Example datafile . . . . . . . . . . . . . . . . . . . . . . . .  47
   Index  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
   Smooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  48
   Acsplines  . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
   Bezier . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
   Csplines . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
   Sbezier  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
   Unique . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
   Frequency  . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
   Special-filenames  . . . . . . . . . . . . . . . . . . . . . . .  50
   Thru . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  52
   Using  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  52
   Errorbars  . . . . . . . . . . . . . . . . . . . . . . . . . . .  55
   Errorlines . . . . . . . . . . . . . . . . . . . . . . . . . . .  56
   Parametric . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
   Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
   Title  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  59
   With . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  59
   Print  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  62
   Pwd  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  62
   Quit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  62
   Replot . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  63
   Reread . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  63
   Reset  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64
   Save . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64
   Set-show . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65
   Angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  66
   Arrow  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
   Autoscale  . . . . . . . . . . . . . . . . . . . . . . . . . . .  69
   Parametric mode  . . . . . . . . . . . . . . . . . . . . . . . .  70
   Polar mode . . . . . . . . . . . . . . . . . . . . . . . . . . .  71
   Bars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  71
   Bmargin  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  72
   Border . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  72
   Boxwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . .  74
   Clabel . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  75
   Clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  75
   Cntrparam  . . . . . . . . . . . . . . . . . . . . . . . . . . .  76










   =1 .if 0 .tl 'GNUPLOT 4.0''%'


   Color box  . . . . . . . . . . . . . . . . . . . . . . . . . . .  78
   Contour  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  79
   Data style . . . . . . . . . . . . . . . . . . . . . . . . . . .  80
   Datafile . . . . . . . . . . . . . . . . . . . . . . . . . . . .  80
   Set datafile missing . . . . . . . . . . . . . . . . . . . . . .  81
   Set datafile separator . . . . . . . . . . . . . . . . . . . . .  82
   Set datafile commentschars . . . . . . . . . . . . . . . . . . .  82
   Decimalsign  . . . . . . . . . . . . . . . . . . . . . . . . . .  83
   Dgrid3d  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  83
   Dummy  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  84
   Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . .  85
   Fit  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  86
   Fontpath . . . . . . . . . . . . . . . . . . . . . . . . . . . .  87
   Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  87
   Format specifiers  . . . . . . . . . . . . . . . . . . . . . . .  88
   Time/date specifiers . . . . . . . . . . . . . . . . . . . . . .  90
   Function style . . . . . . . . . . . . . . . . . . . . . . . . .  91
   Functions  . . . . . . . . . . . . . . . . . . . . . . . . . . .  91
   Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  91
   Hidden3d . . . . . . . . . . . . . . . . . . . . . . . . . . . .  92
   Historysize  . . . . . . . . . . . . . . . . . . . . . . . . . .  95
   Isosamples . . . . . . . . . . . . . . . . . . . . . . . . . . .  95
   Key  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  96
   Label  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  99
   Lmargin  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
   Loadpath . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
   Locale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
   Logscale . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
   Mapping  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
   Margin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
   Mouse  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
   X11_mouse  . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
   Multiplot  . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
   Mx2tics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
   Mxtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
   My2tics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
   Mytics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
   Mztics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
   Offsets  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
   Origin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
   Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
   Parametric . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
   Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
   Pm3d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
   Palette  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
   Rgbformulae  . . . . . . . . . . . . . . . . . . . . . . . . . . 119
   Defined  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
   Functions  . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
   File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
   Gamma-correction . . . . . . . . . . . . . . . . . . . . . . . . 123
   Postscript . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
   Pointsize  . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
   Polar  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125










   GNUPLOT 4.0                                                       iv


   Print  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
   Rmargin  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
   Rrange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
   Samples  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
   Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
   Style  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
   Set style arrow  . . . . . . . . . . . . . . . . . . . . . . . . 129
   Set style data . . . . . . . . . . . . . . . . . . . . . . . . . 130
   Set style fill . . . . . . . . . . . . . . . . . . . . . . . . . 131
   Set style function . . . . . . . . . . . . . . . . . . . . . . . 131
   Set style line . . . . . . . . . . . . . . . . . . . . . . . . . 132
   Plotting styles  . . . . . . . . . . . . . . . . . . . . . . . . 133
   Boxerrorbars . . . . . . . . . . . . . . . . . . . . . . . . . . 134
   Boxes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
   Filledcurves . . . . . . . . . . . . . . . . . . . . . . . . . . 136
   Boxxyerrorbars . . . . . . . . . . . . . . . . . . . . . . . . . 137
   Candlesticks . . . . . . . . . . . . . . . . . . . . . . . . . . 137
   Dots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
   Financebars  . . . . . . . . . . . . . . . . . . . . . . . . . . 138
   Fsteps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
   Histeps  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
   Impulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
   Lines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
   Linespoints  . . . . . . . . . . . . . . . . . . . . . . . . . . 140
   Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
   Steps  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
   Vectors  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
   Xerrorbars . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
   Xyerrorbars  . . . . . . . . . . . . . . . . . . . . . . . . . . 141
   Yerrorbars . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
   Xerrorlines  . . . . . . . . . . . . . . . . . . . . . . . . . . 142
   Xyerrorlines . . . . . . . . . . . . . . . . . . . . . . . . . . 142
   Yerrorlines  . . . . . . . . . . . . . . . . . . . . . . . . . . 142
   Surface  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
   Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
   Aed767 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
   Aifm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
   Amiga  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
   Apollo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
   Aqua . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
   Atari ST (via AES) . . . . . . . . . . . . . . . . . . . . . . . 146
   Be . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
   Command-line_options . . . . . . . . . . . . . . . . . . . . . . 147
   Monochrome_options . . . . . . . . . . . . . . . . . . . . . . . 148
   Color_resources  . . . . . . . . . . . . . . . . . . . . . . . . 148
   Grayscale_resources  . . . . . . . . . . . . . . . . . . . . . . 149
   Line_resources . . . . . . . . . . . . . . . . . . . . . . . . . 150
   Cgi  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
   Cgm  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
   Font . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
   Linewidth  . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
   Rotate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
   Solid  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155










   GNUPLOT 4.0                                                        v


   Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
   Width  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
   Nofontlist . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
   Corel  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
   Debug  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
   Dospc  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
   Dumb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
   Dxf  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
   Dxy800a  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
   Eepic  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
   Emf  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
   Emxvga . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
   Epslatex . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
   Epson-180dpi . . . . . . . . . . . . . . . . . . . . . . . . . . 161
   Excl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
   Fig  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
   Ggi  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
   Gif  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
   Gnugraph(GNU plotutils)  . . . . . . . . . . . . . . . . . . . . 166
   Gpic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
   Gpr  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
   Grass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
   Hercules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
   Hp2623a  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
   Hp2648 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
   Hp500c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
   Hpgl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
   Hpljii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
   Hppj . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
   Imagen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
   Iris4d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
   Jpeg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
   Kyo  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
   Latex  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
   Linux  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
   Macintosh  . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
   Mf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
   METAFONT Instructions  . . . . . . . . . . . . . . . . . . . . . 177
   Mgr  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
   Mif  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
   Mp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
   Metapost Instructions  . . . . . . . . . . . . . . . . . . . . . 182
   Mtos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
   Next . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
   Openstep (next)  . . . . . . . . . . . . . . . . . . . . . . . . 184
   Pbm  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
   Pdf  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
   Pm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
   Png (NEW)  . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
   Png (OLD)  . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
   Postscript . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
   Enhanced postscript  . . . . . . . . . . . . . . . . . . . . . . 191
   Editing postscript . . . . . . . . . . . . . . . . . . . . . . . 193










   GNUPLOT 4.0                                                       vi


   Postscript fontfile  . . . . . . . . . . . . . . . . . . . . . . 193
   Pslatex and pstex  . . . . . . . . . . . . . . . . . . . . . . . 195
   Pstricks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
   Qms  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
   Regis  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
   Rgip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
   Sun  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
   Svg  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
   Svga . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
   Table  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
   Tek40  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
   Tek410x  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
   Texdraw  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
   Tgif . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
   Tkcanvas . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
   Tpic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
   Unixpc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
   Unixplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
   Atari ST (via VDI) . . . . . . . . . . . . . . . . . . . . . . . 204
   Vgagl  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
   VWS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
   Vx384  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
   Windows  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
   Graph-menu . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
   Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
   Text-menu  . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
   Wgnuplot.ini . . . . . . . . . . . . . . . . . . . . . . . . . . 209
   Windows3.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
   X11  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
   X11_fonts  . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
   Command-line_options . . . . . . . . . . . . . . . . . . . . . . 213
   Monochrome_options . . . . . . . . . . . . . . . . . . . . . . . 214
   Color_resources  . . . . . . . . . . . . . . . . . . . . . . . . 214
   Grayscale_resources  . . . . . . . . . . . . . . . . . . . . . . 215
   Line_resources . . . . . . . . . . . . . . . . . . . . . . . . . 216
   X11 pm3d_resources . . . . . . . . . . . . . . . . . . . . . . . 217
   Xlib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
   Tics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
   Ticslevel  . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
   Ticscale . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
   Timestamp  . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
   Timefmt  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
   Title  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
   Tmargin  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
   Trange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
   Urange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
   Variables  . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
   Version  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
   View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
   Vrange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
   X2data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
   X2dtics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
   X2label  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225










   GNUPLOT 4.0                                                      vii


   X2mtics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
   X2range  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
   X2tics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
   X2zeroaxis . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
   Xdata  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
   Xdtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
   Xlabel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
   Xmtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
   Xrange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
   Xtics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
   Xzeroaxis  . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
   Y2data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
   Y2dtics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
   Y2label  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
   Y2mtics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
   Y2range  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
   Y2tics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
   Y2zeroaxis . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
   Ydata  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
   Ydtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
   Ylabel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
   Ymtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
   Yrange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
   Ytics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
   Yzeroaxis  . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
   Zdata  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
   Zdtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
   Cbdata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
   Cbdtics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
   Zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
   Zeroaxis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
   Zlabel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
   Zmtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
   Zrange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
   Ztics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
   Cblabel  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
   Cbmtics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
   Cbrange  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
   Cbtics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
   Shell  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
   Splot  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
   Data-file  . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
   Binary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
   Example datafile . . . . . . . . . . . . . . . . . . . . . . . . 241
   Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
   Grid_data  . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
   Splot_overview . . . . . . . . . . . . . . . . . . . . . . . . . 243
   System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
   Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
   Unset  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
   Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
   Graphical User Interfaces  . . . . . . . . . . . . . . . . . . . 245
   Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246










   GNUPLOT 4.0                                                     viii


   Old_bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246


























































