update packages

[CreaPhase.git] / octave_packages / m / special-matrix / rosser.m

diff --git a/octave_packages/m/special-matrix/rosser.m b/octave_packages/m/special-matrix/rosser.m
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+++ b/octave_packages/m/special-matrix/rosser.m
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+## Copyright (C) 1999-2012 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 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} {} rosser ()
+## Return the Rosser matrix.  This is a difficult test case used to evaluate
+## eigenvalue algorithms.
+##
+## @seealso{wilkinson, eig}
+## @end deftypefn
+
+## Author: Peter Ekberg
+##         (peda)
+
+function retval = rosser ()
+
+  if (nargin != 0)
+    print_usage ();
+  endif
+
+  retval = [611,   196,  -192,   407,    -8,   -52,   -49,    29;
+            196,   899,   113,  -192,   -71,   -43,    -8,   -44;
+           -192,   113,   899,   196,    61,    49,     8,    52;
+            407,  -192,   196,   611,     8,    44,    59,   -23;
+             -8,   -71,    61,     8,   411,  -599,   208,   208;
+            -52,   -43,    49,    44,  -599,   411,   208,   208;
+            -49,    -8,     8,    59,   208,   208,    99,  -911;
+             29,   -44,    52,   -23,   208,   208,  -911,    99];
+
+endfunction
+
+%!assert (size(rosser()), [8,8])
+%!error (rosser(1))