optimization/test_functions/wood_gradient.m

   1 function g = wood_gradient(x1, x2, x3, x4)
   2   ##
   3   ## The gradient of the Wood function. See wood.m for more information.
   4   ##
   5   f_x1 = 400*(x1^2 - x2)*x1 + 2*x1 - 2;
   6   f_x2 = -200*x1^2 + 220.2*x2 + 19.8*x4 - 40;
   7   f_x3 = 360*(x3^2 - x4)*x3 + 2*x3 - 2;
   8   f_x4 = -180*x3^2 + 19.8*x2 + 200.2*x4 - 40;
   9
  10   g = [f_x1; f_x2; f_x3; f_x4];
  11 end