--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rDiff/src/tools/intersect.m	Thu Feb 14 23:38:36 2013 -0500
@@ -0,0 +1,67 @@
+%## Copyright (C) 2000-2012 Paul Kienzle
+%## Copyright (C) 2008-2009 Jaroslav Hajek
+%##
+%## This file is part of Octave.
+%##
+%## Octave 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 3 of the License, or (at
+%## your option) any later version.
+%##
+%## Octave 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 Octave; see the file COPYING.  If not, see
+%## <http://www.gnu.org/licenses/>.
+
+function [c, ia, ib] = intersect (a, b, varargin)
+
+if (nargin < 2 || nargin > 3)
+  print_usage ();
+end
+
+
+if (isempty (a) || isempty (b))
+  c = ia = ib = [];
+else
+  ## form a and b into sets
+  if (nargout > 1)
+    [a, ja] = unique (a, varargin{:});
+    [b, jb] = unique (b, varargin{:});
+  else
+    a = unique (a, varargin{:});
+    b = unique (b, varargin{:});
+  end
+  
+  if (nargin > 2)
+    c = [a; b];
+    [c, ic] = sortrows (c);
+    ii = find (all (c(1:end-1,:) == c(2:end,:), 2));
+    c = c(ii,:);
+    len_a = rows (a);
+  else
+    c = [a(:); b(:)];
+    [c, ic] = sort (c);               ## [a(:);b(:)](ic) == c
+    if (iscellstr (c))
+      ii = find (strcmp (c(1:end-1), c(2:end)));
+    else
+      ii = find (c(1:end-1) == c(2:end));
+    end
+    c = c(ii);
+    len_a = length (a);
+  end
+  
+  if (nargout > 1)
+    ia = ja(ic(ii));                  ## a(ia) == c
+    ib = jb(ic(ii+1) - len_a);        ## b(ib) == c
+  end
+  
+  if (nargin == 2 && (size (b, 1) == 1 || size (a, 1) == 1))
+    c = c.';
+  end
+end