| 摘要 |
A point-to-point shortest path technique supports real-time queries and fast metric update or replacement (metric customization). Arbitrary metrics (cost functions) are supported without significant degradation in performance. Determining a shortest path between two locations uses three stages: a preprocessing stage, a metric customization stage, and a query stage. Preprocessing is based on a graph structure only, while metric customization augments preprocessing results taking edge costs into account. The preprocessing partitions the graph into loosely connected components of bounded size and creates an overlay graph by replacing each component with a clique connecting its boundary vertices. Clique edge lengths are computed during the customization phase. The customization phase can be repeated for various different metrics, and produces a small amount of data for each. The query phase is run using the metric-independent data together with the relevant metric-specific data. |
