Tristram Gräbener schreef: >>> There a good chances that they use an approach similar to that one : >>> >>> Precomputation: >>> - Find 100 × 100 points in europe (that means a point every 30km) >>> - Compute the distance between all those points and store it >>> >>> >>> >> Every 30km? Choose a popular location close to it .. >> > Not really necessary, as anyway you will compute the shortest path to > that point. The goal is only to have a very good distance estimation. > Not the path itself. > Of course being smart while choosing the points will turn out in a > slightly faster solution. Not really a big deal. > > And even choosing a 1000×1000grid (a node every 3km) will only consume > 4 Mb (you just store a duration for every pair of start-destination). > But you will need to run one million times a shortest path algorithm > in before hand. > > This is a variant of distcc or distmp3 (in debian/ubuntu the pkg are called so).
Marc -- What's on Shortwave guide: choose an hour, go! http://whatsonshortwave.tk 700+ Radio Stations on SW http://swstations.tk 300+ languages on SW http://radiolanguages.tk _______________________________________________ Routing mailing list [email protected] http://lists.openstreetmap.org/listinfo/routing
