[Routing] Fast Routing Engine - State of Play

[Dennis Luxen]

> The current implementation can only deal with fixed edge length, thus
> you'd have to precompute a Contraction Hierarchy for every objective
> function you'd like to supply. While dealing with linear combinations
> of objective functions is possible [1], it is quite complex. However,
> the precomputation of Contraction Hierarchies is quite fast and
> techniques used for Mobile Contraction Hierarchies [2] can be used to
> avoid loading the whole Contraction Hierarchy into memory during route
> computations. This makes it possible for a single server to provide a
> larger amount of objective functions while still maintaining fast
> query times.

Chris is right and on an SSD the perfomance penalty would be rather
small if not neglectable. If I only had the time and resources to
implement it... ;-)

Best,
Dennis