An Iterative two Phase Search Based Heuristic to Solve the Capacitated Location- Routing Problem

In this paper we define a new approach to solve the location routing problem (LRP). LRP is a relatively new research direction within location analysis that takes into account vehicle routing aspects. In this study it is proposed an iterative two phase search based heuristic method to solve a capacitated location routing problem. At first an initial solution is produced by a greedy approach and then encoding this initial solution to use in optimization language and then in phase 1, a solution population is generated based on this solution. Among this population, multiple base solutions have been selected and they are improved by various neighborhood search. Solution which has the lowest cost is selected. In phase 2 by using of several algorithms is improved. Finally this solution is compared with the best solution obtained. which has minimum cost is selected as new best solution. New solution population is generated based on this new best solution and the previous steps are repeated for L times. Finally, to verify the quality of our new approach in term of solution quality, two well-known data problem sets is selected. The numerical examples show the efficiency of our approach and provide high quality solutions with the cost no more than 3% (in average).