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