com.graphhopper.routing.ch

Class PrepareContractionHierarchies

java.lang.Object

com.graphhopper.routing.util.AbstractAlgoPreparation

com.graphhopper.routing.ch.PrepareContractionHierarchies

All Implemented Interfaces:

RoutingAlgorithmFactory

public class PrepareContractionHierarchies
extends AbstractAlgoPreparation
implements RoutingAlgorithmFactory

This class prepares the graph for a bidirectional algorithm supporting contraction hierarchies ie. an algorithm returned by createAlgo.

There are several descriptions of contraction hierarchies available. The following is one of the more detailed: http://web.cs.du.edu/~sturtevant/papers/highlevelpathfinding.pdf

The only difference is that we use two skipped edges instead of one skipped node for faster unpacking.

Author:

Peter Karich

Constructor Summary

Constructors

Constructor and Description
PrepareContractionHierarchies(CHGraph chGraph, Weighting weighting, TraversalMode traversalMode)

Method Summary

Modifier and Type	Method and Description
RoutingAlgorithm	createAlgo(Graph graph, AlgorithmOptions opts) This method creates an algorithm out of this factory based on the specified opts and graph.
void	doSpecificWork()
static PrepareContractionHierarchies	fromGraphHopperStorage(GraphHopperStorage ghStorage, Weighting weighting, TraversalMode traversalMode)
long	getDijkstraCount()
double	getLazyTime()
double	getNeighborTime()
double	getPeriodTime()
long	getShortcuts()
Weighting	getWeighting()
boolean	isEdgeBased()
PrepareContractionHierarchies	setParams(PMap pMap)
String	toString()
PrepareContractionHierarchies	useFixedNodeOrdering(NodeOrderingProvider nodeOrderingProvider) Instead of heuristically determining a node ordering for the graph contraction it is also possible to use a fixed ordering.

Methods inherited from class com.graphhopper.routing.util.AbstractAlgoPreparation

doWork, isPrepared

Methods inherited from class java.lang.Object

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

Constructor Detail

PrepareContractionHierarchies

public PrepareContractionHierarchies(CHGraph chGraph,
                                     Weighting weighting,
                                     TraversalMode traversalMode)

Method Detail

fromGraphHopperStorage

public static PrepareContractionHierarchies fromGraphHopperStorage(GraphHopperStorage ghStorage,
                                                                   Weighting weighting,
                                                                   TraversalMode traversalMode)

setParams

public PrepareContractionHierarchies setParams(PMap pMap)

useFixedNodeOrdering

public PrepareContractionHierarchies useFixedNodeOrdering(NodeOrderingProvider nodeOrderingProvider)

Instead of heuristically determining a node ordering for the graph contraction it is also possible to use a fixed ordering. For example this allows re-using a previously calculated node ordering. This will speed up CH preparation, but might lead to slower queries.

doSpecificWork

public void doSpecificWork()

Specified by:

doSpecificWork in class AbstractAlgoPreparation

createAlgo

public RoutingAlgorithm createAlgo(Graph graph,
                                   AlgorithmOptions opts)

Description copied from interface: RoutingAlgorithmFactory

This method creates an algorithm out of this factory based on the specified opts and graph.

Specified by:

createAlgo in interface RoutingAlgorithmFactory

isEdgeBased

public boolean isEdgeBased()

getDijkstraCount

public long getDijkstraCount()

getShortcuts

public long getShortcuts()

getLazyTime

public double getLazyTime()

getPeriodTime

public double getPeriodTime()

getNeighborTime

public double getNeighborTime()

getWeighting

public Weighting getWeighting()

toString

public String toString()

Overrides:

toString in class Object