Iterative Heuristic over Periods for the Inventory Routing Problem

Inventory Routing Problems are specially designed to solve transportation problems with inventory management constraints associated. The objective is to serve a set of customers over a finite time horizon, performing product deliveries to meet the demands of customers taking into account constraints regarding inventory levels authorized as well as production capacity. We propose a heuristic method based on an iterative approach that decomposes the original problem into subproblems according to the length of the time horizon. The proposed method is iterative and follows the sequence of periods of the time horizon from the beginning to the end. Therefore, the resolution of a subproblem (with all initial constraints but considering only a part of the time horizon) starts from the resolution of the subproblems for previous periods. The method limits the modification of the solution for periods that has already been considered at an earlier iteration, thus accelerating the resolution. Results shown that our approach is competitive in terms of solution quality and execution time and can provide good solutions for the set of instances considered.