optimization/test_functions/himmelblau.m

   1 function f = himmelblau(x1, x2)
   2   %
   3   % The eponymous function defined by Himmelblau in his Applied
   4   % Nonlinear Programming, 1972.
   5   %
   6   % It has four identical local minima,
   7   %
   8   %   * f(3,2)                                    == 0
   9   %
  10   %   * f(-2.805118086952745,  3.131312518250573) == 0
  11   %
  12   %   * f(-3.779310253377747, -3.283185991286170) == 0
  13   %
  14   %   * f(3.584428340330492, -1.848126526964404)  == 0
  15   %
  16   f = (x1^2 + x2 - 11)^2 + (x1 + x2^2 - 7)^2;
  17 end