Customizable Contraction Hierarchies

TL;DR

This paper extends Contraction Hierarchies with a fast customization phase, enabling quick shortest path computations in weighted graphs where edge weights frequently change, demonstrated through extensive experiments on large maps.

Contribution

It introduces Customizable Contraction Hierarchies that incorporate a new fast weight-customization step, supporting dynamic edge weights efficiently.

Findings

Effective on large road and game maps

Supports scenarios with frequent edge weight updates

Outperforms previous methods in customization speed

Abstract

We consider the problem of quickly computing shortest paths in weighted graphs given auxiliary data derived in an expensive preprocessing phase. By adding a fast weight-customization phase, we extend Contraction Hierarchies by Geisberger et al to support the three-phase workflow introduced by Delling et al. Our Customizable Contraction Hierarchies use nested dissection orders as suggested by Bauer et al. We provide an in-depth experimental analysis on large road and game maps that clearly shows that Customizable Contraction Hierarchies are a very practicable solution in scenarios where edge weights often change.