Function matyas

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

Matyas test function.

Defined as

$$ f(x_1,\,x_2) = 0.26 (x_1^2 + x_2^2) - 0.48 x_1 x_2 $$

where $x_i \in [-10,\,10]$.

The global minimum is at $f(x_1,\,x_2) = f(0,\,0) = 0$.