s.kcv(1)	       Grass User's Manual		 s.kcv(1)



NNAAMMEE
       ss..kkccvv  -  Randomly  partition  sites into test/train sets.
       _(_G_R_A_S_S _S_i_t_e_s _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       ss..kkccvv

       ss..kkccvv hheellpp

       ss..kkccvv [--ddqq] kk==vvaalluuee ssiitteess=_n_a_m_e

DDEESSCCRRIIPPTTIIOONN
       _s_._k_c_v  randomly	divides  a  sites  lists  into	_k sets of
       test/train data (for kk-fold ccross vvalidation).  Test  par-
       titions	are  mutually  exclusive.  That  is,  a site will
       appear in only one test partition and _k_-_1 training  parti-
       tions.  The  program  generates	a random point using  the
       selected  random number generator and then finds the clos-
       est site to it.	This site is removed from  the	candidate
       list  (meaning  that it will not be selected for any other
       test  set)  and saved  in the first test  partition  file.
       This  is  repeated  until enough points have been selected
       for the test partition.	The  number   of   sites   chosen
       for  test  partitions  depends  upon  the  number of sites
       available and the  number of partitions chosen (this  num-
       ber  is made as consistent as possible while ensuring that
       all sites will be chosen  for testing).	This  process  of
       filling up a test partition is done _k times.

FFllaaggss::
       --dd   Use _d_r_a_n_d_4_8_(_) (default is _r_a_n_d_(_)_)_.

       --qq  Run quietly. Don't report progress.


PPaarraammeetteerrss::
       kk=_v_a_l_u_e		   Positive  integer   value   indicating
       the number of partitions.

       ssiitteess=_n_a_m_e	  Name	of  a  sites  file to store  ran-
       dom points in.


       Test/train  pairs  are saved as sites list using _n_a_m_e as a
       basename. Test sites are saved in _n_a_m_e-test._i while train-
       ing  sites  are saved in _n_a_m_e-train._i, where _i ranges from
       zero to _k_.

NNOOTTEESS
       Existing files are silently overwritten.


       An ideal random sites generator will follow a Poisson  dis
       only be as random as the  original  sites.   This  program
       simply divides sites up in a random manner.


       Be  warned  that  random number generation occurs over the
       intervals defined by the current region.


       This program may not work properly with Lat-long data.

SSEEEE AALLSSOO
       _s_._r_a_n_d_o_m and _g_._r_e_g_i_o_n

BBUUGGSS
       Please  send  all  bug fixes and comments to the author or
       the grass development team.

       http://www.geog.uni-hannover.de/grass/

AAUUTTHHOORR
       James Darrell McCauley ,

       when he was at: Agricultural Engineering Purdue University

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_5 _$



GRASS 5.0						 s.kcv(1)
