1 ## Copyright (C) 1999-2012 Peter Ekberg
3 ## This file is part of Octave.
5 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by
7 ## the Free Software Foundation; either version 3 of the License, or (at
8 ## your option) any later version.
10 ## Octave is distributed in the hope that it will be useful, but
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ## General Public License for more details.
15 ## You should have received a copy of the GNU General Public License
16 ## along with Octave; see the file COPYING. If not, see
17 ## <http://www.gnu.org/licenses/>.
20 ## @deftypefn {Function File} {} rosser ()
21 ## Return the Rosser matrix. This is a difficult test case used to evaluate
22 ## eigenvalue algorithms.
24 ## @seealso{wilkinson, eig}
27 ## Author: Peter Ekberg
30 function retval = rosser ()
36 retval = [611, 196, -192, 407, -8, -52, -49, 29;
37 196, 899, 113, -192, -71, -43, -8, -44;
38 -192, 113, 899, 196, 61, 49, 8, 52;
39 407, -192, 196, 611, 8, 44, 59, -23;
40 -8, -71, 61, 8, 411, -599, 208, 208;
41 -52, -43, 49, 44, -599, 411, 208, 208;
42 -49, -8, 8, 59, 208, 208, 99, -911;
43 29, -44, 52, -23, 208, 208, -911, 99];
47 %!assert (size(rosser()), [8,8])