M2: Six-hump Camel Back function

Minimize:

$$f_{m2}(\vec x)=(4-2.1x_1^2+\frac{x_1^4}{3})x_1^2+x_1x_2+(-4+4x_2^2)x_2^2$$

With constraints:

$$-1.9 \le x_1 \le 1.9,-1.1 \le x_2 \le 1.1$$

2 global optima (and 4 local optima):

$$f_{m2}(\vec x^*)=-1.031628453$$

$${x_1}^*=0.089842,{x_2}^*=-0.712656$$

$${x_1}^*=-0.089842,{x_2}^*=0.712656$$

Features:

Multimodal, Non-separable.

Figure 32: Six-hump Camel Back