Himmelblau is a set of quartic form functions, generally the following is used:
with 
For which there is a set of known local optima of approximately the same importance:
f(3,2) = 0
f(-3.78, -3.28) = 0.0054
f(-2.81, 3.13) = 0.0085
f(3.58, -1.85) = 0.0011
