function [fval]=unc_n2_shubert3(x)
%reference:
%note that you can get the formulation of unc_n2_camel6 from some
%aritcles,such as
%(1)X Liu 'Finding Global Minima with a Computable Filled Function',
%Journal of Global Optimization,151-161'
%
%algorithm:
%below code is  edited according to 
%(1)X Liu 'Finding Global Minima with a Computable Filled Function',
%Journal of Global Optimization,151-161'
%
%solution:
% where the bounds are -10<=x1,x2<=10;
% The global minimum is at x*=(-1.42513,-0.80032) and f(x*)=-186.7309;
%This function has about 400 minima!


%Copyright:
% programmers:oiltowater.
% It comply with the GPL2.0
% Copyright 2006  oiltowater 



a=1.42513;
b=0.80032;

if size(x,1)~=2,
    error('the row of x is 2');
end

x1=x(1,1);
x2=x(2,1);

suma=0;
for i=1:5
suma=suma+i*cos((i+1)*x1+i);
end


sumb=0;
for i=1:5
sumb=sumb+i*cos((i+1)*x2+i);
end


fval=suma*sumb+power(x1+a,2)+power(x2+b,2);