Langermann

class gob.benchmarks.langermann.Langermann(dim=2, m=None, c=None, A=None, seed=42)

Bases: Benchmark

The Langermann function.

\(f(x) = \sum_{i = 1}^m c_i \exp \left( -\frac{1}{\pi} \sum_{j = 1}^d (x_j - A_{ij})^2 \right) \cos \left( \pi \sum_{j = 1}^d (x_j - A_{ij})^2 \right)\). By default, hyper-parameters \(m\), \(A\), and \(c\) are generated randomly with a fixed seed.

Its minimum is unknown.

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