Heuristic algorithms for the capacitated location-routing problem and the multi-depot vehicle routing problem

The Capacitated Location-Routing Problem (CLRP) is a NP-hard problem since it generalizes two well known NP-hard problems: the Capacitated Facility Location Problem (CFLP) and the Capacitated Vehicle Routing Problem (CVRP). The Multi-Depot Vehicle Routing Problem (MDVRP) is known to be a NP-hard since it is a generalization of the well known Vehicle Routing Problem (VRP), arising with one depot. This thesis addresses heuristics algorithms based on the well-know granular search idea introduced by Toth and Vigo [60] to solve the CLRP and the MDVRP. Extensive computational experiments on benchmark instances for both problems have been performed to determine the e ectiveness of the proposed algorithms. This work is organized as follows: ˆ Chapter 1 describes a detailed overview and a methodological review of the literature for the the Capacitated Location-Routing Problem (CLRP) and the Multi-Depot Vehicle Routing Problem (MDVRP). ˆ Chapter 2 describes a two-phase hybrid heuristic algorithm to solve the CLRP. ˆ Chapter 3 shows a computational comparison of heuristic algorithms for the CLRP. ˆ Chapter 4 presents a hybrid granular tabu search approach for solving the MDVRP.