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## Copyright (C) 1995, 1996, 1997 Kurt Hornik
##
## This program 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.
##
## This program 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 this file. If not, write to the Free Software Foundation,
## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
## usage: stdnormal_pdf (x)
##
## For each element of x, compute the probability density function (PDF)
## of the standard normal distribution at x.
## Author: TT <Teresa.Twaroch@ci.tuwien.ac.at>
## Description: PDF of the standard normal distribution
function pdf = stdnormal_pdf (x)
if (nargin != 1)
usage ("stdnormal_pdf (x)");
endif
[r, c] = size (x);
s = r * c;
x = reshape (x, 1, s);
pdf = zeros (1, s);
k = find (isnan (x));
if any (k)
pdf(k) = NaN * ones (1, length (k));
endif
k = find (!isinf (x));
if any (k)
pdf (k) = (2 * pi)^(- 1/2) * exp( - x(k) .^ 2 / 2);
endif
pdf = reshape (pdf, r, c);
endfunction
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