com.sparsity.sparksee.algorithms

Class PageRank

java.lang.Object

com.sparsity.sparksee.algorithms.PageRank

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class PageRank
extends java.lang.Object
implements java.io.Closeable

PageRank class.

Implements the PageRank algorithm

Author:

Sparsity Technologies http://www.sparsity-technologies.com

Constructor Summary

Constructors

Constructor and Description
PageRank(Session session) Builds the PageRank.

Method Summary

Modifier and Type	Method and Description
void	addAllEdgeTypes(EdgesDirection dir) Allows for traversing all edge types of the graph.
void	addAllNodeTypes() Allows for traversing all node types of the graph.
void	addEdgeType(int type, EdgesDirection dir) Allows for traversing edges of the given type.
void	addNodeType(int type) Allows for traversing nodes of the given type.
void	close() Closes the PageRank instance.
boolean	isClosed() Gets if PageRank instance has been closed or not.
void	run() Runs the algorithm.
void	setDamping(double damping) Sets the damping value for the PageRank.
void	setDefaultWeight(double weight) Sets the default weight for those cases when a given edge does not have a weight attribute set.
void	setEdgeWeightAttributeType(int attr) Sets the attribute to use as edge weight.
void	setInitialPageRankValue(double startValue) Sets the initial PageRank value.
void	setNumIterations(int numIterations) Sets the number of iterations to run the PageRank for.
void	setOutputAttributeType(int attr) Sets the output attribute type.
void	setStartingNode(long startNode) Sets the starting node of the page rank to compute the Personalized PageRank variant.
void	setTolerance(double tolerance) Sets the tolerance threashold to continue computing the PageRank after each iteration.

Methods inherited from class java.lang.Object

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

Constructor Detail

PageRank

public PageRank(Session session)

Builds the PageRank.

Parameters:

session - [in] The session to use

Method Detail

setDamping

public void setDamping(double damping)

Sets the damping value for the PageRank.

Parameters:

damping - [in] The damping value. Default: 0.85

setDefaultWeight

public void setDefaultWeight(double weight)

Sets the default weight for those cases when a given edge does not have a weight attribute set.

Default: 0.0

Parameters:

weight - [in] The default weight

run

public void run()
         throws java.lang.RuntimeException

Runs the algorithm.

sparksee::gdb::Error

Throws:

java.lang.RuntimeException - null

addAllEdgeTypes

public void addAllEdgeTypes(EdgesDirection dir)

Allows for traversing all edge types of the graph.

The direction is interpreted as in which direction an edge can be followed from a node to influence other nodes.

Parameters:

dir - [in] Edge direction.

setOutputAttributeType

public void setOutputAttributeType(int attr)
                            throws java.lang.RuntimeException

Sets the output attribute type.

If the PageRank will run on more than one node type, then the output attribute must be of type GLOBAL_TYPE or NODES_TYPE. Otherwise, it must be a valid attribute for the used node type.

Parameters:

attr - [in] The attribute to store the result. Default: InvalidAttribute

Throws:

java.lang.RuntimeException - null

setStartingNode

public void setStartingNode(long startNode)
                     throws java.lang.RuntimeException

Sets the starting node of the page rank to compute the Personalized PageRank variant.

sparksee::gdb::Error

Parameters:

startNode - null

Throws:

java.lang.RuntimeException - null

setInitialPageRankValue

public void setInitialPageRankValue(double startValue)

Sets the initial PageRank value.

If a starting node is set, this initial value is only set for the starting node and the rest of nodes are set to 0.0

Parameters:

startValue - [in] The initial value to set. Default: 0.0

setEdgeWeightAttributeType

public void setEdgeWeightAttributeType(int attr)
                                throws java.lang.RuntimeException

Sets the attribute to use as edge weight.

If the multiple edge are set for traversal, this attribute must be of type GLOBAL_TYPE or EDGES_TYPE. Additionally, the attribute must be of type Double. Finally, negative weights are treated as non existing, so the default weight applies.

sparksee::gdb::Error

Parameters:

attr - [in] The attribute type to use as a weight. Default: InvalidAttribute

Throws:

java.lang.RuntimeException - null

addEdgeType

public void addEdgeType(int type,
                        EdgesDirection dir)
                 throws java.lang.RuntimeException

Allows for traversing edges of the given type.

If the edge type was already added, the existing direction is overwritten The direction is interpreted as in which direction an edge can be followed from a node to influence other nodes.

Parameters:

type - [in] Edge type.

dir - [in] Edge direction.

Throws:

java.lang.RuntimeException - null

setNumIterations

public void setNumIterations(int numIterations)

Sets the number of iterations to run the PageRank for.

Parameters:

numIterations - [in] The number of interations to set. Default: 20

setTolerance

public void setTolerance(double tolerance)

Sets the tolerance threashold to continue computing the PageRank after each iteration.

If all the changes to any PPR value after an iteration are below that tolerance threshold, the algorithm finishes.

Parameters:

tolerance - [in] The tolerance to use normalized between 0 and 1. Default: 0.000001

isClosed

public boolean isClosed()

Gets if PageRank instance has been closed or not.

Returns:

TRUE if the PageRank instance has been closed, FALSE otherwise.

See Also:

close()

addNodeType

public void addNodeType(int type)
                 throws java.lang.RuntimeException

Allows for traversing nodes of the given type.

Parameters:

type - null

Throws:

java.lang.RuntimeException - null

close

public void close()

Closes the PageRank instance.

It must be called to ensure the integrity of all data.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

addAllNodeTypes

public void addAllNodeTypes()

Allows for traversing all node types of the graph.