Unrelated Parallel Machine Scheduling Problem with Precedence Constraints: Polyhedral Analysis and Branch-and-Cut
Abstract
We consider the problem of unrelated parallel machines with precedence constraints (UPMPC), with the aim of minimizing the makespan. Each task has to be assigned to a unique machine and no preemption is allowed. In this paper, we show the relation between the interval graph and the UPMSPC problem. We propose valid inequalities and study the facial structure of their polytope. Facets are presented to strength the associated integer linear program formulation to help in solving the global problem. We develop a Branch and Cut algorithm for solving the problem and present some experimental results.