clear

[x,y] = meshgrid(-100:1:100);
r=size(x,1);
for i=1:r
    for j=1:r
        z(i,j)=max(abs(x(i,j)),abs(y(i,j)));
    end
end
mesh(x,y,z);
title('Schwefel''s Problem 2.21','FontSize',16);
%axis([-100,100,-100,100,0,10000]);