optimization/test_functions/trigonometric1.m

   1 function f = trigonometric1(x)
   2   ##
   3   ## The trigonometric function. See More, Garbow, and Hillstrom,
   4   ## function #26.
   5   ##
   6   ## This function has a minimum with f(x) == 0. The suggested
   7   ## starting point is x0=(1/n, 1/n,...).
   8   ##
   9   n = length(x);
  10   f = 0;
  11
  12   cos_sum = sum(cos(x));
  13
  14   for k = [ 1 : n ]
  15     f_k = n - cos_sum + k*(1 - cos(x(k))) - sin(x(k));
  16     f = f + (f_k)^2;
  17   end
  18 end