Function eggholder_hessian

pub fn eggholder_hessian<T>(param: &[T; 2]) -> [[T; 2]; 2]
where
    T: Float + FromPrimitive,

Hessian of Eggholder test function.

This function can return NaN-valued elements under the following conditions:

• $|x_1 - x_2 - 47| <= \epsilon$ and $x_1 \neq 0$
• $|x_2 - x_1 + 47| <= \epsilon$ and $x_1 \neq 0$
• $\left|\frac{x_1}{2} + x_2 + 47\right| <= \epsilon$ and $|x_2 + 47| \neq 0$

where $\epsilon$ is T’s epsilon.