Mercurial > octave
view scripts/linear-algebra/isbanded.m @ 29358:0a5b15007766 stable
update Octave Project Developers copyright for the new year
In files that have the "Octave Project Developers" copyright notice,
update for 2021.
author | John W. Eaton <jwe@octave.org> |
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date | Wed, 10 Feb 2021 09:52:15 -0500 |
parents | a4268efb7334 |
children | 7854d5752dd2 |
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######################################################################## ## ## Copyright (C) 2014-2021 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 {} {} isbanded (@var{A}, @var{lower}, @var{upper}) ## Return true if @var{A} is a matrix with entries confined between ## @var{lower} diagonals below the main diagonal and @var{upper} diagonals ## above the main diagonal. ## ## @var{lower} and @var{upper} must be non-negative integers. ## @seealso{isdiag, istril, istriu, bandwidth} ## @end deftypefn function retval = isbanded (A, lower, upper) if (nargin != 3) print_usage (); endif if (! isreal (lower) || ! isreal (upper) || lower < 0 || upper < 0) error ("isbanded: LOWER and UPPER must be non-negative integers"); endif if (isempty (A)) retval = []; else retval = (isnumeric (A) || islogical (A)) && ndims (A) == 2; if (retval) [i, j] = find (A); pupp = j >= i; retval = all (j(pupp) - i(pupp) <= upper); if (retval) plow = i >= j; retval = all (i(plow) - j(plow) <= lower); endif endif endif endfunction %!assert (! isbanded ("string", 0, 0)) %!assert (! isbanded (zeros (2,2,2), 0, 0)) %!assert (isbanded ([], 0, 0), []) %!assert (isbanded (1,0,0)) %!assert (isbanded (1,10,10)) %!assert (isbanded ([1, 1],1,1)) %!assert (isbanded ([1; 1],1,1)) %!assert (isbanded (eye(10),0,0)) %!assert (isbanded (eye(10),1,1)) %!assert (isbanded (i*eye(10),1,1)) %!assert (isbanded (logical (eye (10)),1,1)) %! A = [2 3 0 0 0; 1 2 3 0 0; 0 1 2 3 0; 0 0 1 2 3; 0 0 0 1 2]; %! assert (isbanded (A,1,1)); %! assert (! isbanded (A,0,1)); %! assert (! isbanded (A,1,0)); ## Test input validation %!error isbanded () %!error isbanded (1) %!error isbanded (1,2) %!error isbanded (1,2,3,4) %!error <LOWER and UPPER must be non-negative> isbanded (1, -1, 1) %!error <LOWER and UPPER must be non-negative> isbanded (1, 1, -1) %!error <LOWER and UPPER must be non-negative> isbanded (1, {1}, 1) %!error <LOWER and UPPER must be non-negative> isbanded (1, 1, {1})