This multimodal function is defined as $$f(\mathbf{x}) = -\left|\cos(\mathbf{x}_1)\cos(\mathbf{x}_2)\exp(|1 - \sqrt{\mathbf{x}_1 + \mathbf{x}_2}/\pi|)\right|$$ with box-constraints \(\mathbf{x}_i \in [-10, 10], i = 1, 2\).
makeHolderTableN1Function()[smoof_single_objective_function]
S. K. Mishra, Global Optimization By Differential Evolution and Particle Swarm Methods: Evaluation On Some Benchmark Functions, Munich Research Papers in Economics.