Function ackley

pub fn ackley<T>(param: &[T]) -> T
where
    T: Float + FromPrimitive + Sum,

Ackley test function

Defined as

$$ f(x_1, x_2, …, x_n) = -a\exp\left(-b\sqrt{\frac{1}{n}\sum_{i=1}^{n}x_i^2}\right) - \exp\left(\frac{1}{n}\sum_{i=1}^{n}\cos(cx_i)\right) + a + \exp(1) $$

where $x_i \in [-32.768,\,32.768]$ and usually $a = 20$, $b = 0.2$ and $c = 2\pi$.

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