evlevy(x)

function y = evlevy(x)

% Name: Levy
% Reference:
% Levy, A. V., Montalvo, A., Gomez, S., and Calderon, A. (1981), Topics in 
% Global Optimization , Lecture Notes in Mathematics, No. 909, Springer-
% Verlag, Berlin.
% Variables: n
% Initial Point/ Initial Interval: (5,....,5) / ([-10,10],...,[-10,10])
% Reported Solution: (1,....,1)
% Minima: 0
% Matlab Code by A. Hedar (Nov. 23, 2005).

n = length(x);

for i = 1:n
  z(i) = 1+(x(i)-1)/4;
end

s = sin(pi*z(1))^2;

for i = 1:n-1
    s = s+(z(i)-1)^2*(1+10*(sin(pi*z(i)+1))^2);
end 
y = s+(z(n)-1)^2*(1+(sin(2*pi*z(n)))^2);