Mercurial > octave
view scripts/linear-algebra/istriu.m @ 23083:e9a0469dedd9 stable
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author | John W. Eaton <jwe@octave.org> |
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date | Fri, 20 Jan 2017 12:19:08 -0500 |
parents | bac0d6f07a3e |
children | ef4d915df748 3ac9f9ecfae5 |
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## Copyright (C) 2014-2016 Massimiliano Fasi ## ## 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 {} {} istriu (@var{A}) ## Return true if @var{A} is an upper triangular matrix. ## ## An upper triangular matrix has nonzero entries only on the main diagonal and ## above. ## @seealso{isdiag, isbanded, istril, triu, bandwidth} ## @end deftypefn ## Author: Massimiliano Fasi function retval = istriu (A) if (nargin != 1) print_usage (); endif retval = (isnumeric (A) || islogical (A)) && ndims (A) == 2; if (retval) [i, j] = find (A); retval = all (i <= j); endif endfunction %!assert (! istriu ("string")) %!assert (istriu ([])) %!assert (! istriu (zeros (2,2,2))) %!assert (istriu (1)) %!assert (istriu ([1, 1])) %!assert (! istriu ([1; 1])) %!assert (istriu (eye (10))) %!assert (istriu (speye (100))) %!assert (istriu (triu (randn (10)))) %!assert (! istriu (randn (10))) ## Test input validation %!error istriu () %!error istriu (1,2)