Logic-based Benders decomposition for the preemptive flexible job-shop scheduling problem

In this paper, we focus on exact methods to solve the preemptive flexible job-shop scheduling problem with makespan minimisation objective function. Mathematical and constraint programming models enable the resolution of this problem for small instances. However, as an NP-hard problem, the cost of solving grows rapidly when considering larger instances. In this regard, we propose a logic-based Benders decomposition that relies on an efficient branch-and-bound procedure to solve the subproblem representing a pure (non-flexible) preemptive job-shop scheduling problem. Computational experiments are carried out and show the very good performance of our proposals.