Function sphere_derivative_const

pub fn sphere_derivative_const<const N: usize, T>(param: &[T; N]) -> [T; N]
where
    T: Float + FromPrimitive,

Derivative of sphere test function.

Defined as

$$ f(x_1,\,x_2,\,\ldots,\,x_d) = (2x_1,\,2x_2,\,\ldots,\,2x_d) $$

where $x_i \in (-\infty, \infty)$ and $d > 0$.

This is the const generics version, which requires the number of parameters to be known at compile time.