Engineering label-constrained shortest-path algorithms
Christopher Barrett, Keith Bisset, Martin Hölzer, Goran Konjevod, MADHAV V. MARATHE, Dorothea Wagner · DIMACS series in discrete mathematics and theoretical computer science · 2009
We consider a generalization of the shortest-path problem: given an alphabet Σ, a graph Gwhose edges are weighted and Σ-labeled, and a regular language L? Σ*, the L-constrained shortest-path problemconsists of finding a shortest path pin Gsuch that the concatenated labels along pform a word of L. This definition allows to model, e. g., many traffic-planning problems. We present extensions of well-known speed-up techniques for the standard shortest-path problem, and conduct an extensive experimental study of their performance with various networks and language constraints. Our results show that depending on the network type, both goal-directed and bidirectional search speed up the search considerably, while combinations of these do not.