function f=unc_nn_sin(x)
%reference:
%note that you can get the formulation of unc_nn_sin from some
%aritcles,such as
%
%
%algorithm:
%below code is  edited according to 
%
%
% solution:
% where the bounds are -10<=x<=10,
% The global minimum is at x*=ones(n,1),and f(x*)=0;



%Copyright:
% programmers:oiltowater.
% It comply with the GPL2.0
% Copyright 2006  oiltowater 
n=size(x,1);

suma=0;
for i=1:n-1
    suma=(x(i,1)-1).^2*(1+10*sin(pi*x(i+1,1)).^2);
end
suma=10*sin(pi*x(1,1)).^2+suma+(x(n,1)-1).^2;
suma=pi/n*suma;
f=suma;