A parallel shifting bottleneck heuristic for scheduling complex job shops: Architecture and performance assessment

The shifting bottleneck heuristic (SBH) for complex job shops decomposes the overall scheduling problem into a series of scheduling problems related to machine groups. These smaller, more tractable, scheduling problems are called subproblems. The heuristic is based on a disjunctive graph that is used to model the relationship between the subproblems. In this paper, we introduce a parallel implementation of the SBH that is based on the idea that these subproblems are rather independent from each other. We show that the parallel implementation is much faster than the sequential version of the SBH. Hence, more computationally costly subproblem solution procedures (SSP's) can be applied within the parallel shifting bottleneck heuristic.