Two-Phase Particle Swarm Optimization for Multi-depot Location-Routing Problem

The location-routing problem is one of the problems in distribution network designing and logistic management, whose mathematical model is proposed in this paper firstly. Since finding the optimal solution for this model is an NP(non-polynomial)problem, we divide the original problem into two sub-problems, i.e., one is the location-allocation problem and the other is general vehicle routing problem. Each sub-problem is then solved in a sequential and iterative manner by the particle swarm optimization method embedded in the general framework for the problem-solving procedure. From an illustrational example, the availability and performance of proposed PSO can be approved.