Mercurial > octave
view scripts/linear-algebra/istril.m @ 31248:8b75954a4670
delaunayn: adjust node ordering for positive outward normal vectors (bug #53397)
* delaunayn.m: Check sign of simplex volume, flip node order for negative
volumes to ensure positive (outward-pointing) normal vectors. Add BISTs to
check for positive volumes.
* etc/News.8.md: Append function improvement note to delaunayn change
paragraph under General Improvements.
author | Nicholas R. Jankowski <jankowski.nicholas@gmail.com> |
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date | Thu, 29 Sep 2022 23:09:05 -0400 |
parents | 83f9f8bda883 |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2014-2022 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{tf} =} istril (@var{A}) ## Return true if @var{A} is a lower triangular matrix. ## ## A lower triangular matrix has nonzero entries only on the main diagonal and ## below. ## @seealso{istriu, isbanded, isdiag, tril, bandwidth} ## @end deftypefn function tf = istril (A) if (nargin < 1) print_usage (); endif tf = (isnumeric (A) || islogical (A)) && ndims (A) == 2; if (tf) [i, j] = find (A); tf = all (i >= j); endif endfunction %!assert (! istril ("string")) %!assert (istril ([])) %!assert (! istril (zeros (2,2,2))) %!assert (istril (1)) %!assert (! istril ([1, 1])) %!assert (istril ([1; 1])) %!assert (istril (eye (10))) %!assert (istril (speye (100))) %!assert (istril (tril (randn (10)))) %!assert (! istril (randn (10))) ## Test input validation %!error <Invalid call> istril ()