This continuous single-objective test function is defined by the formula $$f(\mathbf{x}) = 10^5\mathbf{x}_1^2 + \mathbf{x}_2^2 - (\mathbf{x}_1^2 + \mathbf{x}_2^2)^2 + 10^{-5} (\mathbf{x}_1^2 + \mathbf{x}_2^2)^4$$ with the bounding box \(-20 \leq \mathbf{x}_i \leq 20\) for \(i = 1, 2\).
makeDeckkersAartsFunction()[smoof_single_objective_function]
M. M. Ali, C. Khompatraporn, Z. B. Zabinsky, A Numerical Evaluation of Several Stochastic Algorithms on Selected Continuous Global Optimization Test Problems, Journal of Global Optimization, vol. 31, pp. 635-672, 2005.