function y = norm_pdf(x,mu,sigma)
%NORM_PDF Normal probability density function (pdf).
%
%   More detailed description goes here.
%
%   Syntax:
%   varargout = norm_pdf(varargin)
%
%   Input:
%   varargin  =
%
%   Output:
%   varargout =
%
%   Example
%   norm_pdf
%
%   See also 

%% Copyright notice
%   --------------------------------------------------------------------
%   Copyright (C) 2011 Deltares
%       Bas Hoonhout
%
%       bas.hoonhout@deltares.nl	
%
%       Rotterdamseweg 185
%       2629HD Delft
%
%   This library is free software: you can redistribute it and/or
%   modify it under the terms of the GNU Lesser General Public
%   License as published by the Free Software Foundation, either
%   version 2.1 of the License, or (at your option) any later version.
%
%   This library 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
%   Lesser General Public License for more details.
%
%   You should have received a copy of the GNU Lesser General Public
%   License along with this library. If not, see <http://www.gnu.org/licenses/>.
%   --------------------------------------------------------------------

% This tool is part of <a href="http://OpenEarth.nl">OpenEarthTools</a>.
% OpenEarthTools is an online collaboration to share and manage data and 
% programming tools in an open source, version controlled environment.
% Sign up to recieve regular updates of this function, and to contribute 
% your own tools.

%% Version <http://svnbook.red-bean.com/en/1.5/svn.advanced.props.special.keywords.html>
% Created: 20 May 2011
% Created with Matlab version: 7.9.0.529 (R2009b)

% $Id$
% $Date$
% $Author$
% $Revision$
% $HeadURL$
% $Keywords: $

%%

if nargin<1
    error('stats:normpdf:TooFewInputs','Input argument X is undefined.');
end
if nargin < 2
    mu = 0;
end
if nargin < 3
    sigma = 1;
end

% Return NaN for out of range parameters.
sigma(sigma <= 0) = NaN;

try
    y = exp(-0.5 * ((x - mu)./sigma).^2) ./ (sqrt(2*pi) .* sigma);
catch
    error('stats:normpdf:InputSizeMismatch',...
          'Non-scalar arguments must match in size.');
end
