Mercurial > octave
view scripts/linear-algebra/issymmetric.m @ 21220:d78e45987d6a
rename octave::build_env namespace from octave::config
* build-env-features.sh: Rename from ocgt-conf-features.sh.
Update for new names.
* build-env.h: Rename from oct-conf.h. Also declare features function.
* build-env.in.cc: Rename from oct-conf.in.cc.
* oct-conf-features.h: Delete.
* libinterp/module.mk: Update.
* toplev.cc, __init_gnuplot__.cc, octave.cc: Update for new names.
author | John W. Eaton <jwe@octave.org> |
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date | Sun, 07 Feb 2016 14:56:17 -0500 |
parents | 516bb87ea72e |
children | bac0d6f07a3e |
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## Copyright (C) 1996-2015 John W. Eaton ## Copyright (C) 2009 VZLU Prague ## ## 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 {} {} issymmetric (@var{A}) ## @deftypefnx {} {} issymmetric (@var{A}, @var{tol}) ## Return true if @var{A} is a symmetric matrix within the tolerance specified ## by @var{tol}. ## ## The default tolerance is zero (uses faster code). ## ## Matrix @var{A} is considered symmetric if ## @code{norm (@var{A} - @var{A}.', Inf) / norm (@var{A}, Inf) < @var{tol}}. ## @seealso{ishermitian, isdefinite} ## @end deftypefn ## Author: A. S. Hodel <scotte@eng.auburn.edu> ## Created: August 1993 ## Adapted-By: jwe function retval = issymmetric (A, tol = 0) if (nargin < 1 || nargin > 2) print_usage (); endif retval = (isnumeric (A) || islogical (A)) && issquare (A); if (retval) if (tol == 0) ## Handle large sparse matrices as well as full ones retval = nnz (A != A.') == 0; else norm_x = norm (A, inf); retval = norm_x == 0 || norm (A - A.', inf) / norm_x <= tol; endif endif endfunction %!assert (issymmetric (1)) %!assert (! issymmetric ([1, 2])) %!assert (issymmetric ([])) %!assert (issymmetric ([1, 2; 2, 1])) %!assert (! (issymmetric ("test"))) %!assert (issymmetric ([1, 2.1; 2, 1.1], 0.2)) %!assert (issymmetric ([1, 2i; 2i, 1])) %!assert (! (issymmetric ("t"))) %!assert (! (issymmetric (["te"; "et"]))) %!assert (issymmetric (speye (100000))) %!assert (issymmetric (logical (eye (2)))) %!test %! s.a = 1; %! assert (! issymmetric (s)); %!error issymmetric ([1, 2; 2, 1], 0, 0) %!error issymmetric ()