Unimodal function with its global optimum in the center of the search space. The attraction area of the global optimum is very small in relation to the search space: $$f(\mathbf{x}) = -\cos(\mathbf{x}_1)\cos(\mathbf{x}_2)\exp\left(-\left((\mathbf{x}_1 - \pi)^2 + (\mathbf{x}_2 - pi)^2\right)\right)$$ with \(\mathbf{x}_i \in [-100, 100], i = 1,2.\)
makeEasomFunction()[smoof_single_objective_function]
Easom, E. E.: A survey of global optimization techniques. M. Eng. thesis, University of Louisville, Louisville, KY, 1990.