New Exact Algorithms for One-Machine Earliness-Tardiness Scheduling

In one-machine scheduling, mixed-integer program time-indexed formulations are often used to provide very good lower bounds through Lagrangian relaxations. To get an improved lower bound, we add valid cuts to a time-indexed formulation and show we still have a Lagrangian relaxation that can be solved as a shortest path in a graph. Two branch-and-bound algorithms are then presented for the earliness-tardiness scheduling problem with either common or general due dates. In both cases, our algorithms outperform the previously published approaches.