org.opentripplanner.routing.algorithm.strategies

Class EuclideanRemainingWeightHeuristic

java.lang.Object

org.opentripplanner.routing.algorithm.strategies.EuclideanRemainingWeightHeuristic

All Implemented Interfaces:

Serializable, RemainingWeightHeuristic

public class EuclideanRemainingWeightHeuristic
extends Object
implements RemainingWeightHeuristic

A Euclidean remaining weight strategy that takes into account transit boarding costs where applicable.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
EuclideanRemainingWeightHeuristic()

Method Summary

Modifier and Type	Method and Description
void	doSomeWork() Call to cause the heuristic to perform some predetermined amount of work improving its estimate.
double	estimateRemainingWeight(State s) On a non-transit trip, the remaining weight is simply distance / street speed.
void	initialize(RoutingRequest options, long abortTime) Perform any one-time setup and pre-computation that will be needed by later calls to computeForwardWeight/computeReverseWeight.
void	reset() Reset any cached data in the heuristic, before reuse in a search with the same destination.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EuclideanRemainingWeightHeuristic

public EuclideanRemainingWeightHeuristic()

Method Detail

initialize

public void initialize(RoutingRequest options,
                       long abortTime)

Description copied from interface: RemainingWeightHeuristic

Perform any one-time setup and pre-computation that will be needed by later calls to computeForwardWeight/computeReverseWeight. We may want to start from multiple origin states, so initialization cannot depend on the origin vertex or state.

Specified by:

initialize in interface RemainingWeightHeuristic

abortTime - time since the Epoch in milliseconds at which we should bail out of initialization, or Long.MAX_VALUE for no limit.

estimateRemainingWeight

public double estimateRemainingWeight(State s)

On a non-transit trip, the remaining weight is simply distance / street speed. On a transit trip, there are two cases: (1) we're not on a transit vehicle. In this case, there are two possible ways to compute the remaining distance, and we take whichever is smaller: (a) walking distance / walking speed (b) boarding cost + transit distance / transit speed (this is complicated a bit when we know that there is some walking portion of the trip). (2) we are on a transit vehicle, in which case the remaining weight is simply transit distance / transit speed (no need for boarding cost), again considering any mandatory walking.

Specified by:

estimateRemainingWeight in interface RemainingWeightHeuristic

reset

public void reset()

Description copied from interface: RemainingWeightHeuristic

Reset any cached data in the heuristic, before reuse in a search with the same destination.

Specified by:

reset in interface RemainingWeightHeuristic

doSomeWork

public void doSomeWork()

Description copied from interface: RemainingWeightHeuristic

Call to cause the heuristic to perform some predetermined amount of work improving its estimate. Avoids thread synchronization evil by interleaving forward and backward searches.

Specified by:

doSomeWork in interface RemainingWeightHeuristic