--- /dev/null
+## Copyright (C) 2001-2012 Paul Kienzle
+## Copyright (C) 2009 VZLU Prague
+##
+## 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/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} perms (@var{v})
+##
+## Generate all permutations of @var{v}, one row per permutation. The
+## result has size @code{factorial (@var{n}) * @var{n}}, where @var{n}
+## is the length of @var{v}.
+##
+## As an example, @code{perms([1, 2, 3])} returns the matrix
+##
+## @example
+## @group
+## 1 2 3
+## 2 1 3
+## 1 3 2
+## 2 3 1
+## 3 1 2
+## 3 2 1
+## @end group
+## @end example
+## @end deftypefn
+
+function A = perms (v)
+ if (nargin != 1)
+ print_usage ();
+ endif
+ v = v(:);
+ n = length (v);
+
+ if (n == 0)
+ A = [];
+ else
+ A = v(1);
+ for j = 2:n
+ B = A;
+ A = zeros (prod (2:j), n, class (v));
+ k = size (B, 1);
+ idx = 1:k;
+ for i = j:-1:1
+ A(idx,1:i-1) = B(:,1:i-1);
+ A(idx,i) = v(j);
+ A(idx,i+1:j) = B(:,i:j-1);
+ idx += k;
+ endfor
+ endfor
+ endif
+endfunction
+
+%!error perms ();
+%!error perms (1, 2);
+
+%!assert (perms ([1,2,3]), [1,2,3;2,1,3;1,3,2;2,3,1;3,1,2;3,2,1]);
+%!assert (perms (1:3), perms ([1,2,3]));
+
+%!assert (perms (int8([1,2,3])), int8([1,2,3;2,1,3;1,3,2;2,3,1;3,1,2;3,2,1]));