## 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} {} binomial_rnd (@var{n}, @var{p}, @var{r}, @var{c}) ## @deftypefnx {Function File} {} binomial_rnd (@var{n}, @var{p}, @var{sz}) ## Return an @var{r} by @var{c} or a @code{size (@var{sz})} matrix of ## random samples from the binomial distribution with parameters @var{n} ## and @var{p}. Both @var{n} and @var{p} must be scalar or of size ## @var{r} by @var{c}. ## ## If @var{r} and @var{c} are omitted, the size of the result matrix is ## the common size of @var{n} and @var{p}. ## @end deftypefn ## Author: KH ## Description: Random deviates from the binomial distribution function rnd = binomial_rnd (n, p, r, c) if (nargin > 1) if (!isscalar(n) || !isscalar(p)) [retval, n, p] = common_size (n, p); if (retval > 0) error ("binomial_rnd: n and p must be of common size or scalar"); endif endif endif if (nargin == 4) if (! (isscalar (r) && (r > 0) && (r == round (r)))) error ("binomial_rnd: r must be a positive integer"); endif if (! (isscalar (c) && (c > 0) && (c == round (c)))) error ("binomial_rnd: c must be a positive integer"); endif sz = [r, c]; if (any (size (n) != 1) && ((length (size (n)) != length (sz)) || any (size (n) != sz))) error ("binomial_rnd: n and must be scalar or of size [r, c]"); endif elseif (nargin == 3) if (isscalar (r) && (r > 0)) sz = [r, r]; elseif (isvector(r) && all (r > 0)) sz = r(:)'; else error ("binomial_rnd: r must be a postive integer or vector"); endif if (any (size (n) != 1) && ((length (size (n)) != length (sz)) || any (size (n) != sz))) error ("binomial_rnd: n and must be scalar or of size sz"); endif elseif (nargin == 2) sz = size(n); else usage ("binomial_rnd (n, p, r, c)"); endif if (isscalar (n) && isscalar (p)) if (find (!(n > 0) | !(n < Inf) | !(n == round (n)) | !(p >= 0) | !(p <= 1))) rnd = NaN * ones (sz); else nel = prod (sz); tmp = rand (n, nel); ind = (1 : n)' * ones (1, nel); rnd = (tmp < ones (n, nel) * p) & (ind <= ones (n, nel) * n); rnd = reshape(rnd, sz); endif else rnd = zeros (sz); k = find (!(n > 0) | !(n < Inf) | !(n == round (n)) | !(p >= 0) | !(p <= 1)); if (any (k)) rnd(k) = NaN; endif k = find ((n > 0) & (n < Inf) & (n == round (n)) & (p >= 0) & (p <= 1)); if (any (k)) N = max (n(k)); L = length (k); tmp = rand (N, L); ind = (1 : N)' * ones (1, L); rnd(k) = sum ((tmp < ones (N, 1) * p(k)(:)') & (ind <= ones (N, 1) * n(k)(:)')); endif endif endfunction