Maximising the Net Present Value for Resource-Constrained Project Scheduling

摘要

The Resource-constrained Project Scheduling Problem (Rcpsp), in which a schedule must obey the resource constraints and the precedence constraints between pairs of activities, is one of the most studied scheduling problems. An important variation of the problem (RcpspDc) is to find a schedule which maximises the net present value (discounted cash flow), when every activity has a given cash flow associated with it. Given the success of lazy clause generation (Lcg) approaches to solve Rcpsp with and without generalised precedence relations it seems worthwhile investigating Log's use on RcpspDc. To do so, we must construct propagators for the net-present-value constraint that explain their propagation to the Lcg solver. In this paper we construct three different propagators for net-present-value constraints, and show how they can be used to rapidly solve RcpspDc.