diff scripts/special-matrix/sylvester_matrix.m @ 3140:990ea337e950

[project @ 1998-02-03 08:07:51 by jwe]
author jwe
date Tue, 03 Feb 1998 08:07:51 +0000
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+## Copyright (C) 1996, 1997 John W. Eaton
+##
+## 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, 59 Temple Place - Suite 330, Boston, MA
+## 02111-1307, USA.
+
+## usage: sylvester_matrix (k)
+##
+## Return the Sylvester matrix of order n = 2^k.
+##
+## See also: hankel, vander, hilb, invhilb, toeplitz
+
+## Author: jwe
+
+function retval = sylvester_matrix (k)
+
+  if (nargin != 1)
+    usage ("sylvester_matrix (n)");
+  endif
+
+  if (is_scalar (k))
+    if (k < 1)
+      retval = 1;
+    else
+      tmp = sylvester_matrix (k-1);
+      retval = [tmp, tmp; tmp, -tmp];
+    endif
+  else
+    error ("sylvester_matrix: expecting scalar argument");
+  endif
+
+endfunction