##### Copyright (C) 1997-2009 ABINIT group (XG)
This file is distributed under the terms of the GNU General Public License, see ~abinit/COPYING or http://www.gnu.org/copyleft/gpl.txt .
For the initials of contributors, see ~abinit/doc/developers/contributors.txt .

    This directory, wannier90, contains tests which exercise parts
    of the ABINIT package, related to the features needed to use the Wannier90 library.
    This file gives first a very brief description
    of the tests, then a much longer one.

    These tests are designed primarily to exercise parts of the code
    quickly, NOT necessarily to give physically sensible results.
    For tests of correctness, see directory physics (under development).
    For greater speed, some tests are not run to full convergence.
    Also the quality parameters (especially ecut) are minimal, i.e.
    the calculations are underconverged.

    A classification of the tests is provided now. Later, each test is described
    in more detail, with accompanying notes and references (some of the notes
    might have to be updated, due to the small possible drift related to improvement
    of the accuracy of the code).

    Test 1 is related to ... (to be continued)

    To run these tests, do the following:

    0. Be sure that the perl script "run-standard-tests", in the main directory,
       has been generated from the primitive file "run-standard-tests.pl",
       thanks to the command "make perl"
       issued in ~abinit (see the installation notes on the Web).

    1. Submit the "run-standard-tests" script, specifying a machine, and
       the keyword "fast" (for Tests_fast) and either
       the index of a test case, i.e.
       (run-standard-tests name_of_machine fast 22) >& log_file
       or a whole range of test cases (two indices), i.e.
       (run-standard-tests name_of_machine fast 02 08) >& log_file
       or, if you want to run all the test cases of this directory
       (run-standard-tests name_of_machine fast) >& log_file
       This will send stdout and stderr to log_file.
       The script 'run-standard-tests', will create a subdirectory of
       ~abinit/tests/fast, with the name_of_machine and the date, where
       all the results will be placed.

    2. In that directory, you will find for each test case that you have
       run, a log file (with the name of the test case), an output
       file, but also a 'diff.xxx' file, automatically created by making
       a 'diff' with respect to the "ibmtest" subdirectory output files,
       and a 'difnew.xxx' file, automatically created by making
       a 'diff' with respect to the "Refs" subdirectory output files.
       The first one contains output files from the Plane_Wave code,
       while the second one contains output files from a recent version
       of the ABINIT code.
       There may be large differences in timing but there should only
       be minor differences in the output of physical quantities.

    3. There is also a global report file, generated by the use of the
       fldiff script. Its name is fldiff.report . See the last
       version of the  ~abinit/doc/install_notes/install** file
       in the Infos directory for information about the use of this file.
       This file is the most convenient for a quick look at the correctness
       of results. When the results are not correct, one has often to
       rely on the 'difnew.xxx' file to understand what was going wrong.

    **********

    Test cases:

    01. Gallium Arsenide, zinc-blende
        8 bands. prtwant=2
        Should still be completed by the call to wannier90, and subsequent fldiff
        use...

    02. The same as in 01 but using PAW.

    03.  Si fcc, in primitive cell (2 atoms/cell)
         Test of self-consistent model GW (2 iterations) following Faleev et al.,
         [PRL 93, 126406 (2004)] followed by construction of quasiparticle
         maximally-localized wannier functions [Hamann & Vanderbilt,
         arXiv:0810.3616v1 (cond-mat.mtrl-sci)].  Cutoffs are set for test-
         acceptable speed, and the results are poorly converged.  The input
         file is sufficiently annotated to serve as a model.  Note that well-
         converged GW calculations are extremely time consuming, and in general
         is is advisable to run the SCGW part separately on a parallel system,
         and then run a separate serial job modeled on the last dataset,
         substituting "irdwfk" and "irdqps" for "getwfk" and "getqps," with
         appropriate links to the files produced in the serial run.  Note that
         the _DEN file from the first dataset is also needed as input, although
         the discontinued "irdden" input variable is not needed or supported.
         Note that acceptable names for the secondary input file needed by the
         wannier90 library are wannier90.win, w90.win, abo_DSn_w90.win (ndtset
         >0) and abo_w90.win (ndtset=0), where abo is the 4th line of the .files
         file and n is the wannier dataset.