Mercurial > octave
view scripts/sparse/spfun.m @ 31237:e3016248ca5d
uifigure.m: Call set () only if varargin is not empty (bug #63088)
* uifigure.m: Call set () only if varargin is not empty.
author | John Donoghue <john.donoghue@ieee.org> |
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date | Wed, 21 Sep 2022 09:55:32 -0400 |
parents | 796f54d4ddbf |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2004-2022 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{y} =} spfun (@var{f}, @var{S}) ## Compute @code{f (@var{S})} for the nonzero elements of @var{S}. ## ## The input function @var{f} is applied only to the nonzero elements of ## the input matrix @var{S} which is typically sparse. The function @var{f} ## can be passed as a string, function handle, or inline function. ## ## The output @var{y} is a sparse matrix with the same sparsity structure as ## the input @var{S}. @code{spfun} preserves sparsity structure which is ## different than simply applying the function @var{f} to the sparse matrix ## @var{S} when @code{@var{f} (0) != 0}. ## ## Example ## ## Sparsity preserving @code{spfun} versus normal function application ## ## @example ## @group ## S = pi * speye (2,2) ## S = ## ## Compressed Column Sparse (rows = 2, cols = 2, nnz = 2 [50%]) ## ## (1, 1) -> 3.1416 ## (2, 2) -> 3.1416 ## ## y = spfun (@@cos, S) ## y = ## ## Compressed Column Sparse (rows = 2, cols = 2, nnz = 2 [50%]) ## ## (1, 1) -> -1 ## (2, 2) -> -1 ## @end group ## ## @group ## y = cos (S) ## y = ## ## Compressed Column Sparse (rows = 2, cols = 2, nnz = 4 [100%]) ## ## (1, 1) -> -1 ## (2, 1) -> 1 ## (1, 2) -> 1 ## (2, 2) -> -1 ## ## @end group ## @end example ## @seealso{arrayfun, cellfun, structfun} ## @end deftypefn function y = spfun (f, S) if (nargin != 2) print_usage (); endif if (! isnumeric (S)) error ("spfun: S must be numeric"); endif [i, j, v] = find (S); [m, n] = size (S); y = sparse (i, j, feval (f, v), m, n); endfunction %!assert (spfun ("exp", [1,2;3,0]), sparse ([exp(1),exp(2);exp(3),0])) %!assert (spfun ("exp", sparse ([1,2;3,0])), sparse ([exp(1),exp(2);exp(3),0])) %!assert (spfun (@exp, [1,2;3,0]), sparse ([exp(1),exp(2);exp(3),0])) %!assert (spfun (@exp, sparse ([1,2;3,0])), sparse ([exp(1),exp(2);exp(3),0])) ## Test input validation %!error <Invalid call> spfun () %!error <Invalid call> spfun (@cos) %!error <S must be numeric> spfun (@cos, {1}) %!error <S must be numeric> spfun (@cos, "FooBar")