A high-performance exact method for the resource-constrained project scheduling problem

This paper describes an efficient exact algorithm for project scheduling with resource constraints. The procedure consists of creating partial schedules which are always feasible with respect to both precedence and resource constraints. These partial schedules are connected through a tree, and a lower bound on the comletion of the uncompleted activities is associated with each partial schedule. The branching process takes place from a partial schedule with the minimum lower bound and continues until the optimal schedule is created. Despite branching from a partial schedule with the minimum lower bound, the algorithm does not need large memory for keeping partial schedules as independent data, and does not require large comparability time for selecting a partial schedule to branch from. These make it possible to solve test problems each involving up to 100 activities and six different resource types. The computational results of the performance of the algorithm are reported.