Search Algorithm for the Constraint Satisfaction Problem of VRPTW

This paper presents an algorithm called CSP-IRPTW for the vehicles routing problem with time windows (VRPTW), which applies the PCP method (precedence constraint posting) used for models of scheduling as a CSP (constraint satisfaction problem). PCP involves the calculation of the shortest path in partial and global form, between pairs of nodes and among all the nodes respectively, in the graph that represents the VRPTW model. In order to apply PCP to VRPTW, the problem is treated as a CSP. The results show that the proposed search algorithm is efficient in the search for the global optimum for some problems.