Mercurial > octave
view scripts/statistics/distributions/laplace_rnd.m @ 4859:265d566cc770
[project @ 2004-04-08 23:52:45 by jwe]
author | jwe |
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date | Thu, 08 Apr 2004 23:52:45 +0000 |
parents | 22bd65326ec1 |
children | 4c8a2e4e0717 |
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## Copyright (C) 1995, 1996, 1997 Kurt Hornik ## ## 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 2, 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, write to the Free ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA ## 02111-1307, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} laplace_rnd (@var{r}, @var{c}) ## @deftypefnx {Function File} {} laplace_rnd (@var{sz}); ## Return an @var{r} by @var{c} matrix of random numbers from the ## Laplace distribution. Or is @var{sz} is a vector, create a matrix of ## @var{sz}. ## @end deftypefn ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> ## Description: Random deviates from the Laplace distribution function rnd = laplace_rnd (r, c) if (nargin == 2) if (! (isscalar (r) && (r > 0) && (r == round (r)))) error ("laplace_rnd: r must be a positive integer"); endif if (! (isscalar (c) && (c > 0) && (c == round (c)))) error ("laplace_rnd: c must be a positive integer"); endif sz = [r, c]; elseif (nargin == 1) if (isscalar (r) && (r > 0)) sz = [r, r]; elseif (isvector(r) && all (r > 0)) sz = r(:)'; else error ("laplace_rnd: r must be a postive integer or vector"); endif else usage ("laplace_rnd (r, c)"); endif tmp = rand (sz); rnd = ((tmp < 1/2) .* log (2 * tmp) - (tmp > 1/2) .* log (2 * (1 - tmp))); endfunction