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(Directory dir, GraphHopperStorage ghStorage, 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()
long	getDijkstraCount()
double	getLazyTime()
double	getNeighborTime()
double	getPeriodTime()
long	getShortcuts()
Weighting	getWeighting()
protected void	runGraphContraction()
PrepareContractionHierarchies	setContractedNodes(double nodesContracted) Define how many nodes (percentage) should be contracted.
PrepareContractionHierarchies	setLazyUpdates(int lazyUpdates)
PrepareContractionHierarchies	setLogMessages(double logMessages) Specifies how often a log message should be printed.
PrepareContractionHierarchies	setNeighborUpdates(int neighborUpdates)
PrepareContractionHierarchies	setPeriodicUpdates(int periodicUpdates) The higher the values are the longer the preparation takes but the less shortcuts are produced.
String	toString()

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(Directory dir,
                                     GraphHopperStorage ghStorage,
                                     CHGraph chGraph,
                                     Weighting weighting,
                                     TraversalMode traversalMode)

Method Detail

setPeriodicUpdates

public PrepareContractionHierarchies setPeriodicUpdates(int periodicUpdates)

The higher the values are the longer the preparation takes but the less shortcuts are produced.

Parameters:

periodicUpdates - specifies how often periodic updates will happen. Use something less than 10.

setLazyUpdates

public PrepareContractionHierarchies setLazyUpdates(int lazyUpdates)

Parameters:

lazyUpdates - specifies when lazy updates will happen, measured relative to all existing nodes. 100 means always.

setNeighborUpdates

public PrepareContractionHierarchies setNeighborUpdates(int neighborUpdates)

Parameters:

neighborUpdates - specifies how often neighbor updates will happen. 100 means always.

setLogMessages

public PrepareContractionHierarchies setLogMessages(double logMessages)

Specifies how often a log message should be printed. Specify something around 20 (20% of the start nodes).

setContractedNodes

public PrepareContractionHierarchies setContractedNodes(double nodesContracted)

Define how many nodes (percentage) should be contracted. Less nodes means slower query but faster contraction duration.

doSpecificWork

public void doSpecificWork()

Specified by:

doSpecificWork in class AbstractAlgoPreparation

runGraphContraction

protected void runGraphContraction()

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

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