Solving resource‐constrained project scheduling problems by a* search

Abstract

A new exact method is presented for finding a minimum makespan schedule for a multiresource constrained project scheduling problem. This method employs the philosophical approach used earlier to develop a successful heuristic algorithm for the same class of problems. The approach repairs resource conflicts rather than constructing detailed schedules by dispatching activities. Resource‐violating sets of activities are identified whose concurrent execution would violate resource constraints. Repairs are made by imposing a precedence constraint to sequence two activities in such a resource‐violating set. Computational results are discussed for a standard set of test problems. An A* algorithm is employed. The most successful version of our algorithm involves some perhaps surprising design choices which might be relevant to the design of A*‐like search algorithms in other contexts. Copyright © 1990 Wiley Periodicals, Inc., A Wiley Company