function z = prob_saddle_surface_x2z_test(varargin)
%PROB_SADDLE_SURFACE_X2Z_TEST  Saddle surface limit state function
%
%   Limit state function for a saddle surface problem with
%   various reliability methods
%   Test case obtained from Waarts (2000)
%
%   Syntax:
%   z = saddle_surface_x2z_test(varargin)
%
%   Input:
%   varargin  = propertyName-propertyValue pairs of samples
%
%   Output:
%   z         = array with resulting z-values
%
%   Example
%   saddle_surface_x2z_test
%
%   See also

%% Copyright notice
%   --------------------------------------------------------------------
%   Copyright (C) 2011 Deltares
%       Kees den Heijer
%
%       Kees.denHeijer@Deltares.nl
%
%       Deltares
%       P.O. Box 177
%       2600 MH Delft
%       The Netherlands
%
%   This library 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.
%
%   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 General Public License for more details.
%
%   You should have received a copy of the GNU General Public License
%   along with this library.  If not, see <http://www.gnu.org/licenses/>.
%   --------------------------------------------------------------------

% This tool is part of <a href="http://www.OpenEarth.eu">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: 15 Aug 2011
% Created with Matlab version: 7.7.0.471 (R2008b)

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

%%
OPT = struct(...
    'U1', [],...
    'U2', []);

OPT = setproperty(OPT, varargin{:});

%% Limit state function
z = 3 - OPT.U1.*OPT.U2;