diff main/general/sortrows.m @ 0:6b33357c7561 octave-forge

Initial revision
author pkienzle
date Wed, 10 Oct 2001 19:54:49 +0000
parents
children 7c7be07e7805
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main/general/sortrows.m	Wed Oct 10 19:54:49 2001 +0000
@@ -0,0 +1,61 @@
+## Copyright (C) 2000 Daniel Calvelo
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+## B = sortrows (A)
+##     returns matrix with rows sorted "lexicographically" (i.e., 
+##
+## B = sortrows(A, c)
+##     returns matrix with rows sorted according to the order of the
+##     columns specified in c.
+##
+## Set implicit_str_to_num_ok and implicit_num_to_str_ok to 1 if you 
+## use this for string sorting.
+
+## Author: Daniel Calvelo
+## 2001-02-24 Paul Kienzle
+##    * cleanup according to Octave conventions
+##    * return reverse index
+##    * handle string arguments
+
+function [s, i] = sortrows (m, c)
+  
+  if nargin < 2
+    indices = [ 1 : size(m,2) ]';
+  else
+    indices = c (:);
+  endif
+
+  if (isstr (m)) 
+    s = toascii (m);
+  else
+    s = m;
+  endif
+
+  ## since sort is 'stable' the order of identical elements will be
+  ## preserved, so by traversing the sort indices in reverse order
+  ## we will make sure that identical elements in index i are subsorted
+  ## by index j.
+  indices = flipud (indices);
+  i = [1 : size(m,1)]';
+  for ii = 1 : length (indices);
+    [ trash, idx ] = sort ( s ( : , indices (ii) ) ); 
+    s = s ( idx, : );
+    i = i (idx );
+  endfor
+  if (isstr (m))
+    s = setstr(s);
+  endif
+endfunction