--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/set/unique.m	Sun Feb 27 20:51:35 2005 +0000
@@ -0,0 +1,90 @@
+## Copyright (C) 2000-2001 Paul Kienzle
+##
+## 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
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} unique (@var{x})
+##
+## Return the unique elements of @var{x}, sorted in ascending order.
+## If @var{x} is a row vector, return a row vector, but if @var{x}
+## is a column vector or a matrix return a column vector.
+##
+## @deftypefnx {Function File} {} unique (@var{A}, 'rows')
+##
+## Return the unique rows of @var{A}, sorted in ascending order.
+##
+## @deftypefnx {Function File} {[@var{y}, @var{i}, @var{j}] = } unique (@var{x})
+##
+## Return index vectors @var{i} and @var{j} such that @code{x(i)==y} and
+## @code{y(i)==x}.
+##
+## @end deftypefn
+## @seealso{union, intersect, setdiff, setxor, ismember}
+
+function [y, i, j] = unique (x, r)
+
+  if ( nargin < 1 || nargin > 2 || (nargin == 2 && !strcmp(r,"rows")) )
+    usage ("unique (x) or unique (x, 'rows')");
+  endif
+
+  if (nargin == 1)
+    n = prod(size(x));
+  else
+    n = size(x,1);
+  endif
+
+  y = x; 
+  if (n < 1)
+    i = j = [];
+    return
+  elseif (n < 2)
+    i = j = 1;
+    return
+  endif
+
+  if isstr(x), y = toascii(y); endif
+
+  if nargin == 2
+    [y, i] = sortrows(y);
+    match = all( [ y(1:n-1,:) == y(2:n,:) ]' );
+    idx = find (match);
+    y (idx, :) = [];
+  else
+    if (size(y,1) != 1) y = y(:); endif
+    [y, i] = sort(y);
+    match = [ y(1:n-1) == y(2:n) ];
+    idx = find (match);
+    y (idx) = [];
+  endif
+
+  ## I don't know why anyone would need reverse indices, but it
+  ## was an interesting challenge.  I welcome cleaner solutions.
+  if (nargout >= 3)
+    j = i;
+    j (i) = cumsum ( prepad ( ~match, n, 1 ) );
+  endif
+  i (idx) = [];
+
+  if isstr(x), y = setstr(y); endif
+
+endfunction
+
+%!assert(unique([1 1 2; 1 2 1; 1 1 2]),[1;2])
+%!assert(unique([1 1 2; 1 0 1; 1 1 2],'rows'),[1 0 1; 1 1 2])
+%!assert(unique([]),[])
+%!assert(unique([1]),[1])
+%!assert(unique([1 2]),[1 2])
+%!assert(unique([1;2]),[1;2])
+%!assert(unique([1,NaN,Inf,NaN,Inf]),[1,Inf,NaN,NaN])