Constrained Optimization by the ε Constrained Hybrid Algorithm of Particle Swarm Optimization and Genetic Algorithm

Abstract

The e constrained method is an algorithm transformation method, which can convert algorithms for unconstrained problems to algorithms for constrained problems using the e level comparison that compares search points based on the constraint violation of them. We proposed the e constrained particle swarm optimizer ePSO, which is the combination of the e constrained method and particle swarm optimization. The ePSO can run very fast and find very high quality solutions, but the ePSO is not very stable and sometimes can only find lower quality solutions. On the contrary, the eGA, which is the combination of the e constrained method and GA, is very stable and can find high quality solutions, but it is difficult for the eGA to find higher quality solutions than the ePSO. In this study, we propose the hybrid algorithm of the ePSO and the eGA to find very high quality solutions stably. The effectiveness of the hybrid algorithm is shown by comparing it with various methods on well known nonlinear constrained problems.