Formula:
$$f(x) = -\sum_{i=1}^{4} c_i \exp\left(-\sum_{j=1}^{6} a_{ij}(x_j - p_{ij})^2\right)$$
where \(a_{ij}\), \(c_i\), and \(p_{ij}\) are predefined constants.
Global minimum:
\(f(0.20169, 0.150011, 0.476874, 0.275332, 0.311652, 0.6573) \approx -3.32237\)
Characteristics:
The Hartmann 6D function is more challenging than the 3D version due to
the higher dimensionality.