Constraint pre-checking and gene build-in delaying GA for optimizing large-scale distribution networks

To optimize large-scale distribution networks, it is required to solve large-scale vehicle routing problems (VRP) with in interactive response time, with practicable optimality. To satisfy the requirement, a constraint pre-checking method and a gene build-in delaying GA are proposed. This gene build-in delaying GA postpones the reproduction of genes whose fitness cannot be determined only by local conditions, and preferentially reproduces genes which have stronger relation to just reconstructed genes. Moreover, constraint pre-checking method adopts the constraint propagation method into the GA. This method statistically analyses constraints on the VRP, before starting GA and generates a two dimensional array. This array shows the node, which cannot be contained together in one truck route. Therefore, the calculation efficiency of the crossover and mutation operations is improved by using this array in reconstructing individuals. Our experiments prove that this method enables interactive simulations of large-scale distribution networks.