2009/08/11 by Robert Geisberger, Geisberger, Robert
Computer Science · #Data Structures and Algorithms (cs.DS) #FOS: Computer and information sciences #G.2.2 #cs.DS
paper · pdf · doi:10.48550/arxiv.0908.1528
15 pages, technical report
arxiv created 2009/08/12 · arxiv updated 2009/12/01
We successfully contract timetable networks with realistic transfer times. Contraction gradually removes nodes from the graph and adds shortcuts to preserve shortest paths. This reduces query times to 1 ms with preprocessing times around 6 minutes on all tested instances. We achieve this by an improved contraction algorithm and by using a station graph model. Every node in our graph has a one-to-one correspondence to a station and every edge has an assigned collection of connections. Our graph model does not need parallel edges. The query algorithm does not compute a single earliest arrival time at a station but a set of arriving connections that allow best transfer opportunities.