Solving a class of two-resource allocation problem by equivalent load method

We present an efficient algorithm for solving a class of two-resource allocation problem defined on a series-parallel graph, where nodes represent tasks of a given project and arcs represent precedence relationships. Two separate workloads are associated with each task and the time to complete a workload is inversely proportional to the amount of resource allocated. The time to complete a task is the maximum of the times taken to complete the two workloads. The problem is to allocate the two resources across the project so as to minimize the project duration. The proposed algorithm is derived based on the Equivalent Load Method by Monma, Schrijver, Todd, and Wei for the single-resource allocation problem.