%# Copyright (C) 1995, 1996, 1997, 2005, 2006, 2007 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 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} {} lognrnd (@var{mu}, @var{sigma}, @var{r}, @var{c})
%# @deftypefnx {Function File} {} lognrnd (@var{mu}, @var{sigma}, @var{sz})
%# Return an @var{r} by @var{c} matrix of random samples from the
%# lognormal distribution with parameters @var{mu} and @var{sigma}. Both
%# @var{mu} and @var{sigma} must be scalar or of size @var{r} by @var{c}.
%# Or if @var{sz} is a vector, create a matrix of size @var{sz}.
%#
%# If @var{r} and @var{c} are omitted, the size of the result matrix is
%# the common size of @var{mu} and @var{sigma}.
%# @end deftypefn
%# Author: KH <Kurt.Hornik@wuwien.ac.at>
%# Description: Random deviates from the log normal distribution
function rnd = lognrnd (mu, sigma, r, c)
if (nargin > 1)
if (~isscalar(mu)  ~isscalar(sigma))
[retval, mu, sigma] = common_size (mu, sigma);
if (retval > 0)
rnd = 1;
end
end
end
if (nargin == 4)
if (~ (isscalar (r) && (r > 0) && (r == round (r))))
rnd = 1;
end
if (~ (isscalar (c) && (c > 0) && (c == round (c))))
rnd = 1;
end
sz = [r, c];
if (any (size (mu) ~= 1) && ...
((length (size (mu)) ~= length (sz))  any (size (mu) ~= sz)))
rnd = 1;
end
elseif (nargin == 3)
if (isscalar (r) && (r > 0))
sz = [r, r];
elseif (isvector(r) && all (r > 0))
sz = r(:)';
else
rnd = 1;
end
if (any (size (mu) ~= 1) && ...
((length (size (mu)) ~= length (sz))  any (size (mu) ~= sz)))
rnd = 1;
end
elseif (nargin == 2)
sz = size(mu);
else
print_usage ();
end
if (isscalar (mu) && isscalar (sigma))
if (~(sigma > 0)  ~(sigma < Inf))
rnd = NaN * ones (sz);
else
rnd = exp(mu + sigma .* randn (sz));
end
else
rnd = exp (mu + sigma .* randn (sz));
k = find ((sigma < 0)  (sigma == Inf));
if (any (k))
rnd(k) = NaN;
end
end
