Himmelblau

Himmelblau function is defined as

It has one local maximum at (-0.270844,-0.923038) where f(x,y)=181.616 and four identical local minima:

• f(3,2)=0
• f(-2.805118,3.131312)=0
• f(-3.779310,-3028186)=0
• f(3.584428,-1.848126)=0