The Cyclic Inventory Routing Problem (CIRP) is concerned with finding a cyclic schedule for the distribution of a single product to a number of customers. The problem involves multiple vehicles that can be dispatched several times during their shift. Each customer has a local inventory capacity, a constant consumption rate and stockouts are not allowed. The goal is to compose multiple trips which serve all customers and minimize the combination of transportation, inventory and vehicle costs, in a cyclic distribution pattern. Each trip can have a different frequency in the vehicle schedule. This is an important aspect that makes this so called CIRP, with its non-linear non-convex objective function and a set of non-linear constraints, more complex than the basic Inventory Routing Problem (IRP).
['Masoud Chitsaz', 'Ali Divsalar', 'Pieter Vansteenwegen']
A two-phase algorithm for the cyclic inventory routing problem