A derivative-free algorithm for linearly constrained finite minimax problems. (English) Zbl 1131.90074
Summary: We propose a new derivative-free algorithm for linearly constrained finite minimax problems. Due to the nonsmoothness of this class of problems, standard derivative-free algorithms can locate only points which satisfy weak necessary optimality conditions. In this work we define a new derivative-free algorithm which is globally convergent toward standard stationary points of the finite minimax problem. To this end, we convert the original problem into a smooth one by using a smoothing technique based on the exponentialpenalty function of Kort and Bertsekas. This technique depends on a smoothing parameter which controls the approximation to the finite minimax problem. The proposed method is based on a sampling of the smooth function along a suitable search direction and on a particular updating rule for the smoothing parameter that depends on the sampling stepsize. Numerical results on a set of standard minimax test problems are reported.
MSC:
90C56 | Derivative-free methods and methods using generalized derivatives |
90C47 | Minimax problems in mathematical programming |
65K05 | Numerical mathematical programming methods |