function [X, f1] =D eJong7(Xi)
n = 20;
A = 10;
                         %setting boundary and function
LL = -5.12;              %Lower limit
UL = 5.12;               %Upper limit
X = LL + rand(1,n)*(UL - LL);% step1 Choose starting design X, 
f1 = 20*A + sum(X.^2 - 10*cos(2*pi*X));
end