%
% -------------------------------------------------------------------------
% This file is part of BayesOpt, an efficient C++ library for
% Bayesian optimization.
%
% Copyright (C) 2011-2013 Ruben Martinez-Cantin
%
% BayesOpt 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.
%
% BayesOpt 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 BayesOpt. If not, see .
% ------------------------------------------------------------------------
%
function y = ackley(x)
% Bounds -32.768, 32.768
% Min x = zeros, y = 0
n = length(x);
a = 20;
b = 0.2;
c = 2*pi;
ccx = cos(c*x);
y = -a*exp(-b*sqrt(sum(x.^2)/n)) - exp(sum(ccx)/n) + a + exp(1);