An Efficient Constraint Programming Approach to Preemptive Job Shop Scheduling

TL;DR: It is observed that a large class of preemptive disjunctive scheduling problems do not require an explicit model of task interruptions, and a new constraint programming approach is introduced that significantly outperforms state-of-the-art dedicated approaches.

Abstract: Constraint Programming has been widely, and very successfully, applied to scheduling problems. However, the focus has been on uninterruptible tasks, and preemptive scheduling problems are typically harder for existing constraint solvers. Indeed, one usually needs to represent all potential task interruptions thus introducing many variables and symmetrical or dominated choices. In this paper, building on mostly known results, we observe that a large class of preemptive disjunctive scheduling problems do not require an explicit model of task interruptions. We then introduce a new constraint programming approach for this class of problems that significantly outperforms state-of-the-art dedicated approaches in our experimental results