--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/special-matrix/pascal.m	Mon May 22 06:25:14 2006 +0000
@@ -0,0 +1,73 @@
+## Copyright (C) 1999 Peter Ekberg
+##
+## 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 2, 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, write to the Free
+## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+## 02110-1301, USA.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} pascal (@var{n}, @var{t})
+##
+## Return the Pascal matrix of order @var{n} if @code{@var{t} = 0}.
+## @var{t} defaults to 0. Return lower triangular Cholesky factor of 
+## the Pascal matrix if @code{@var{t} = 1}. This matrix is its own
+## inverse, that is @code{pascal (@var{n}, 1) ^ 2 == eye (@var{n})}.
+## If @code{@var{t} = 2}, return a transposed and  permuted version of
+## @code{pascal (@var{n}, 1)}, which is the cube-root of the identity
+## matrix. That is @code{pascal (@var{n}, 2) ^ 3 == eye (@var{n})}.
+##
+## @seealso{hankel, vander, sylvester_matrix, hilb, invhilb, toeplitz
+##           hadamard, wilkinson, compan, rosser}
+## @end deftypefn
+
+## Author: Peter Ekberg
+##         (peda)
+
+function retval = pascal (n, t)
+
+  if (nargin > 2) || (nargin == 0)
+    print_usage ();
+  endif
+
+  if (nargin == 1)
+    t = 0;
+  endif
+
+  if (! is_scalar (n) || ! is_scalar (t))
+    error ("pascal: expecting scalar arguments, found something else");
+  endif
+
+  retval = diag ((-1).^[0:n-1]);
+  retval(:,1) = ones (n, 1);
+
+  for j = 2:n-1
+    for i = j+1:n
+      retval(i,j) = retval(i-1,j) - retval(i-1,j-1);
+    endfor
+  endfor
+
+  if (t == 0)
+    retval = retval*retval';
+  elseif (t == 2)
+    retval = retval';
+    retval = retval(n:-1:1,:);
+    retval(:,n) = -retval(:,n);
+    retval(n,:) = -retval(n,:);
+    if (rem(n,2) != 1)
+      retval = -retval;
+    endif
+  endif
+
+endfunction