1######################################################################## 2## 3## Copyright (C) 1999-2021 The Octave Project Developers 4## 5## See the file COPYRIGHT.md in the top-level directory of this 6## distribution or <https://octave.org/copyright/>. 7## 8## This file is part of Octave. 9## 10## Octave is free software: you can redistribute it and/or modify it 11## under the terms of the GNU General Public License as published by 12## the Free Software Foundation, either version 3 of the License, or 13## (at your option) any later version. 14## 15## Octave is distributed in the hope that it will be useful, but 16## WITHOUT ANY WARRANTY; without even the implied warranty of 17## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18## GNU General Public License for more details. 19## 20## You should have received a copy of the GNU General Public License 21## along with Octave; see the file COPYING. If not, see 22## <https://www.gnu.org/licenses/>. 23## 24######################################################################## 25 26## -*- texinfo -*- 27## @deftypefn {} {} rosser () 28## Return the @nospell{Rosser} matrix. 29## 30## This is a difficult test case used to evaluate eigenvalue algorithms. 31## @seealso{wilkinson, eig} 32## @end deftypefn 33 34function retval = rosser () 35 36 if (nargin != 0) 37 print_usage (); 38 endif 39 40 retval = [611, 196, -192, 407, -8, -52, -49, 29; 41 196, 899, 113, -192, -71, -43, -8, -44; 42 -192, 113, 899, 196, 61, 49, 8, 52; 43 407, -192, 196, 611, 8, 44, 59, -23; 44 -8, -71, 61, 8, 411, -599, 208, 208; 45 -52, -43, 49, 44, -599, 411, 208, 208; 46 -49, -8, 8, 59, 208, 208, 99, -911; 47 29, -44, 52, -23, 208, 208, -911, 99]; 48 49endfunction 50 51 52%!assert (size (rosser ()), [8,8]) 53%!assert (rosser ()([1, end]), [611, 99]) 54 55%!error (rosser (1)) 56