The mixed algorithm for vehicle routing problem with simultaneous pick-up and delivery

This paper designs a mixed algorithm called PSO_ACS to solve the vehicle routing problem with simultaneous pick-up and delivery. The ACS and PSO are combined by defining information heuristic factor and expectation heuristic factor as the functions of the particle´s positions, and the PSO algorithm is adopted to improve the heuristics parameters self-adaptively. This algorithm improves the convergent speed through changing the inertial weight of the PSO. The results of the numerical experiments on the Dethloff instances show that the mixed algorithm could get better value in efficient time.