update packages

[CreaPhase.git] / octave_packages / m / statistics / distributions / stdnormal_pdf.m

diff --git a/octave_packages/m/statistics/distributions/stdnormal_pdf.m b/octave_packages/m/statistics/distributions/stdnormal_pdf.m
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+## Copyright (C) 2012 Rik Wehbring
+## Copyright (C) 1995-2012 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} {} stdnormal_pdf (@var{x})
+## For each element of @var{x}, compute the probability density function
+## (PDF) at @var{x} of the standard normal distribution (mean = 0,
+## standard deviation = 1).
+## @end deftypefn
+
+## Author: TT <Teresa.Twaroch@ci.tuwien.ac.at>
+## Description: PDF of the standard normal distribution
+
+function pdf = stdnormal_pdf (x)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  if (iscomplex (x))
+    error ("stdnormal_pdf: X must not be complex");
+  endif
+
+  pdf = (2 * pi)^(- 1/2) * exp (- x .^ 2 / 2);
+
+endfunction
+
+
+%!shared x,y
+%! x = [-Inf 0 1 Inf];
+%! y = 1/sqrt(2*pi)*exp (-x.^2/2);
+%!assert(stdnormal_pdf ([x, NaN]), [y, NaN], eps);
+
+%% Test class of input preserved
+%!assert(stdnormal_pdf (single([x, NaN])), single([y, NaN]), eps("single"));
+
+%% Test input validation
+%!error stdnormal_pdf ()
+%!error stdnormal_pdf (1,2)
+%!error stdnormal_pdf (i)
+