Mercurial > octave
view scripts/sparse/speye.m @ 25054:6652d3823428 stable
maint: Update copyright dates in all source files.
author | John W. Eaton <jwe@octave.org> |
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date | Fri, 30 Mar 2018 09:19:05 -0400 |
parents | 194eb4bd202b |
children | 00f796120a6d |
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## Copyright (C) 2004-2018 David Bateman and Andy Adler ## ## 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{s} =} speye (@var{m}, @var{n}) ## @deftypefnx {} {@var{s} =} speye (@var{m}) ## @deftypefnx {} {@var{s} =} speye (@var{sz}) ## Return a sparse identity matrix of size @var{m}x@var{n}. ## ## The implementation is significantly more efficient than ## @code{sparse (eye (@var{m}))} as the full matrix is not constructed. ## ## Called with a single argument a square matrix of size ## @var{m}-by-@var{m} is created. If called with a single vector argument ## @var{sz}, this argument is taken to be the size of the matrix to create. ## @seealso{sparse, spdiags, eye} ## @end deftypefn function s = speye (m, n) if (nargin == 1) if (isvector (m) && length (m) == 2) n = m(2); m = m(1); elseif (isscalar (m)) n = m; else error ("speye: invalid matrix dimension"); endif else if (! isscalar (m) || ! isscalar (n)) error ("speye: invalid matrix dimension"); endif endif lo = min ([m, n]); s = sparse (1:lo, 1:lo, 1, m, n); endfunction %!assert (issparse (speye (4))) %!assert (speye (4), sparse (1:4,1:4,1)) %!assert (speye (2,4), sparse (1:2,1:2,1,2,4)) %!assert (speye (4,2), sparse (1:2,1:2,1,4,2)) %!assert (speye ([4,2]), sparse (1:2,1:2,1,4,2))