## Mercurial > hg > octave-max

### view scripts/sparse/speye.m @ 15489:481417a57a2d

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improve sign and signbit docs
* mappers.cc (Fsign): Note sign (-0) is 0. Add @seealso for signbit.
(Fsignbit): Add @seealso for sign.

author | John W. Eaton <jwe@octave.org> |
---|---|

date | Thu, 04 Oct 2012 10:20:59 -0400 |

parents | 5d3a684236b0 |

children |

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## Copyright (C) 2004-2012 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 ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {@var{y} =} speye (@var{m}) ## @deftypefnx {Function File} {@var{y} =} speye (@var{m}, @var{n}) ## @deftypefnx {Function File} {@var{y} =} speye (@var{sz}) ## Return a sparse identity matrix. This 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. Otherwise a matrix of @var{m} by @var{n} is ## created. If called with a single vector argument, this argument ## is taken to be the size of the matrix to create. ## @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))