function [fval]=unc_n2_camel6(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'
%(2)http://web.ift.uib.no/~antonych/RGA4.html#dixon
%
%algorithm:
%below code is  edited according to 
%(1)X Liu 'Finding Global Minima with a Computable Filled Function',
%Journal of Global Optimization,151-161'
%(2)http://web.ift.uib.no/~antonych/RGA4.html#dixon
%
%solution:
% where the bounds are -3<=x1,x2<=3;
% The global minimum is at x*=(  .0898, -0.7127) or(-0.0898, 0.7127 ),and f(x*)=  -1.0316;


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



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

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

fval=4*x1*x1-2.1*(x1.^4)+(x1.^6)/3+x1*x2-4*x2.^2+4*x2.^4;