[Mathlib-commitlog] SF.net SVN: mathlib:[495] JMathLib/trunk/src/jmathlib/toolbox/polynomial/ polyvalm.m

[<st_...@us...>]

Revision: 495
          http://mathlib.svn.sourceforge.net/mathlib/?rev=495&view=rev
Author:   st_mueller
Date:     2008-11-23 11:29:10 +0000 (Sun, 23 Nov 2008)

Log Message:
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Added Paths:
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    JMathLib/trunk/src/jmathlib/toolbox/polynomial/polyvalm.m

Added: JMathLib/trunk/src/jmathlib/toolbox/polynomial/polyvalm.m
===================================================================
--- JMathLib/trunk/src/jmathlib/toolbox/polynomial/polyvalm.m	                        (rev 0)
+++ JMathLib/trunk/src/jmathlib/toolbox/polynomial/polyvalm.m	2008-11-23 11:29:10 UTC (rev 495)
@@ -0,0 +1,69 @@
+## Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2004,
+##               2005, 2006, 2007 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 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} {} polyvalm (@var{c}, @var{x})
+## Evaluate a polynomial in the matrix sense.
+##
+## @code{polyvalm (@var{c}, @var{x})} will evaluate the polynomial in the
+## matrix sense, i.e. matrix multiplication is used instead of element by
+## element multiplication as is used in polyval.
+##
+## The argument @var{x} must be a square matrix.
+## @seealso{polyval, poly, roots, conv, deconv, residue, filter,
+## polyderiv, polyinteg}
+## @end deftypefn
+
+## Author: Tony Richardson <ari...@st...>
+## Created: June 1994
+## Adapted-By: jwe
+
+function y = polyvalm (c, x)
+
+  if (nargin != 2)
+    print_usage ();
+  endif
+
+  if (! (isvector (c) || isempty (c)))
+    error ("polyvalm: first argument must be a vector");
+  endif
+
+  if (! issquare (x))
+    error ("polyvalm: second argument must be a square matrix");
+  endif
+
+  if (isempty (c))
+    y = [];
+    return;
+  endif
+
+  [v, d] = eig (x);
+
+  if (issymmetric (x))
+    y = v * diag (polyval (c, diag (d))) * v';
+  else
+    y = v * (diag (polyval (c, diag (d))) / v);
+  endif
+
+endfunction
+
+%!assert(isempty (polyvalm ([], [1, 2; 3, 4])));
+
+%!error polyvalm ([1, 1, 1], [1, 2; 3, 4; 5, 6]);
+


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