Function argmin_testfunctions::picheny

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

Picheny test function

Variation of the Goldstein-Price test function.

Defined as

f(x_1, x_2) = (1/2.427) * log([1 + (\bar{x}_1 + \bar{x}_2 + 1)^2 * (19 - 14*\bar{x}_2 + 3*\bar{x}_1^2 - 14*\bar{x}_2 6*\bar{x}_1*\bar{x}_2 + 3*\bar{x}_2^2)] * [30 + (2*\bar{x}_1 - 3*\bar{x}_2)^2(18 - 32 * \bar{x}_1 + 12* \bar{x}_1^2 + 48 * \bar{x}_2 - 36 * \bar{x}_1 * \bar{x}_2 + 27 * \bar{x}_2^2) ] - 8.693)

where \bar{x}_i = 4*x_i - 2 and x_i \in [0, 1].

The global minimum is at f(x_1, x_2) = f(0.5, 0.25) = 3.3851993182036826.