This test function is based on the formula $$f(\mathbf{x}) = (\mathbf{x}_1 - 13 + ((5 - \mathbf{x}_2)\mathbf{x}_2 - 2)\mathbf{x}_2)^2 + (\mathbf{x}_1 - 29 + ((\mathbf{x}_2 + 1)\mathbf{x}_2 - 14)\mathbf{x}_2)^2$$ subject to \(\mathbf{x}_i \in [-10, 10], i = 1, 2\).
makeFreudensteinRothFunction()[smoof_single_objective_function]
S. S. Rao, Engineering Optimization: Theory and Practice, John Wiley & Sons, 2009.