  In this paper, we consider a fundamental and hard combinatorial problem: the
Resource Constrained Shortest Path Problem (RCSPP). We describe the
implementation of a flexible, open-source library for the solution of the
RCSPP, called PathWise, capable of tackling several variants of the problem. We
designed PathWise with the final user in mind, developing easy-to-use
interfaces without compromising performance. We provide computational
experiments on three classes of instances of the RCSPP, namely RCSPP on cyclic
networks, RCSPP on large acyclic networks, and RCSPP on ad-hoc cyclic networks.
We show that PathWise is packed off-the-shelf with algorithms capable of
tackling all classes. This paper represents the first step along the journey of
devising and implementing a comprehensive open-source library for a large
variety of RCSPPs. The current version of the library carries exact algorithms
for the RCSPP but new algorithms, both heuristic and exact, will be added
thanks to the flexible design. We also foresee PathWise becoming a platform
ready for data-driven and process-driven methodologies for these types of
problems.
