A comparison of routing algorithms in a hybrid evolutionary tool for the Inventory and Transportation Problem

In this paper we propose new advances towards the development of a commercial tool to address the inventory and transportation problem, i.e. the problem of minimising both the transport and inventory costs of a retail chain that is supplied from a central warehouse. On the first level, we employ an evolutionary algorithm to evolve the delivery patterns for each shop. On a second level we obtain the delivery routes using two different algorithms: the bi-directional multistart sweep (daisy) algorithm and the daisy algorithm enhanced with local neighbourhood search. The experiments performed show that both methods can obtain acceptable results consistently and within a short timescale. The results are also of a lower cost than those obtained by other strategies employed in previous research, showing that employing a more efficient routing algorithm is effective in reducing costs, although for the cases studied the reduction is not significant. Furthermore, they confirm the interest of addressing the optimisation problem jointly, rather than minimising separately inventory and transport.