This paper presents an original hybrid approach to solve the Capacitated Vehicle Routing Problem (CVRP). The approach combines
a Probabilistic Algorithm with Constraint Programming (CP) and Lagrangian Relaxation (LR). After introducing the CVRP and
reviewing the existing literature on the topic, the paper proposes an approach based on a probabilistic Variable Neighbourhood
Search (VNS) algorithm. Given a CVRP instance, this algorithm uses a randomized version of the classical Clarke and Wright
Savings constructive heuristic to generate a starting solution. This starting solution is then improved through a local search
process which combines: (a) LR to optimise each individual route, and (b) CP to quickly verify the feasibility of new proposed
solutions. The efficiency of our approach is analysed after testing some well-known CVRP benchmarks. Benefits of our hybrid
approach over already existing approaches are also discussed. In particular, the potential flexibility of our methodology
is highlighted.
Keywords Hybrid algorithms – Variable Neighborhood Search – Vehicle Routing Problem – Probabilistic algorithms
Mathematics Subject Classification (2010) 90