Styblinski-Tang

class gob.benchmarks.styblinskitang.Styblinskitang

Bases: Benchmark

The Styblinski-Tang function. This function is normalized by the dimension of x to ensure stability of the minimum.

\(f(x) = \frac{1}{2d}\sum_{i=1}^d (x_i^4 - 16 x_i^2 + 5x_i)\).

Its minimum is \(-39.16599\) achieved at \(x_i = -2.903534\).

expr(x)

The expression of the function.

Parameters:

x (array-like) – The point at which to evaluate the function.

Returns:

The value of the function at x.

Return type:

float