Solving the resource constrained project scheduling problem with optimization subroutine library

In this paper we present three new models for the resource constrained project scheduling problem, using two objective functions: minimizing the makespan and maximizing the net present value of the cash flows of the activities. In these models, compared to the models in the literature, we relax one of the most constraining assumptions about the integrality of the activity durations and the project time line. Furthermore resources are assumed to be partially-renewable. These models have multiple uses in Operations Management in that they can be used to solve resource constrained MRP problems. The models are found to be amenable to solution using the Optimization Subroutine Library (OSL). Extensive computational experiments with OSL on a total of 1400 problems with different parameter settings are reported. Detailed analysis is done to determine the factors that affect the computational efficiency of the code and the models. In general, results demonstrate that OSL is a powerful tool for solving the models with either objective function. Optimal solutions are obtained with reasonable computational effort. A discussion of the application of several special features of OSL is also given.