1 function H = powell_hessian(x1, x2, x3, x4)
3 % The Hessian of the Powell function. See powell.m for more
8 H(1,1) = 120*(x1 - x4)^2 + 2;
11 H(1,4) = -120*(x1 - x4)^2;
14 H(2,2) = 12*(x2 - 2*x3)^2 + 200;
15 H(2,3) = -24*(x2 - 2*x3)^2;
20 H(3,3) = 48*(x2 - 2*x3)^2 + 10;
26 H(4,4) = 120*(x1 - x4)^2 + 10;