com.sparsity.sparksee.algorithms

Class StrongConnectivityGabow

java.lang.Object

com.sparsity.sparksee.algorithms.Connectivity

com.sparsity.sparksee.algorithms.StrongConnectivity

com.sparsity.sparksee.algorithms.StrongConnectivityGabow

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class StrongConnectivityGabow
extends StrongConnectivity

This class can be used to solve the problem of finding strongly connected components in a directed graph.

It consists in finding components where every pair (u,v) of nodes contained in it has a path from u to v using the specified direction for each edge type. This implementation is based on the Gabow algorithm.

It is possible to set some restrictions after constructing a new instance of this class and before running it in order to limit the results.

After the execution, we can retrieve the results stored in an instance of the ConnectedComponents class using the GetConnectedComponents method.

Check out the 'Algorithms' section in the SPARKSEE User Manual for more details on this.

Author:

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

Constructor Summary

Constructors

Constructor and Description
StrongConnectivityGabow(Session session) Creates a new instance of StrongConnectivityGabow.

Method Summary

Modifier and Type	Method and Description
void	addAllEdgeTypes(EdgesDirection dir) Allows connectivity through all edge types of the graph.
void	addAllNodeTypes() Allows connectivity through all node types of the graph.
void	addEdgeType(int type, EdgesDirection dir) Allows connectivity through edges of the given type.
void	addNodeType(int t) Allows connectivity through nodes of the given type.
void	excludeEdges(Objects edges) Set which edges can't be used.
void	excludeNodes(Objects nodes) Set which nodes can't be used.
ConnectedComponents	getConnectedComponents() Returns the results generated by the execution of the algorithm.
void	run() Executes the algorithm.
void	setMaterializedAttribute(java.lang.String attributeName) Creates a new common attribute type for all node types in the graph in order to store, persistently, the results related to the connected components found while executing this algorithm.

Methods inherited from class com.sparsity.sparksee.algorithms.Connectivity

close, isClosed

Methods inherited from class java.lang.Object

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

Constructor Detail

StrongConnectivityGabow

public StrongConnectivityGabow(Session session)

Creates a new instance of StrongConnectivityGabow.

After creating this instance is required to indicate the set of edge types and the set of node types which will be navigated through while traversing the graph in order to find the strong connected components.

Parameters:

session - [in] Session to get the graph from and calculate the connectivity

Method Detail

addEdgeType

public void addEdgeType(int type,
                        EdgesDirection dir)

Allows connectivity through edges of the given type.

Overrides:

addEdgeType in class StrongConnectivity

Parameters:

type - [in] Edge type.

dir - [in] Edge direction.

excludeNodes

public void excludeNodes(Objects nodes)

Set which nodes can't be used.

This will replace any previously specified set of excluded nodes. Should only be used to exclude the usage of specific nodes from allowed node types because it's less efficient than not allowing a node type.

Overrides:

excludeNodes in class StrongConnectivity

Parameters:

nodes - [in] A set of node identifiers that must be kept intact until the destruction of the class.

getConnectedComponents

public ConnectedComponents getConnectedComponents()

Returns the results generated by the execution of the algorithm.

These results contain information related to the connected components found as the number of different components, the set of nodes contained in each component or many other data.

Overrides:

getConnectedComponents in class StrongConnectivity

Returns:

Returns an instance of the class ConnectedComponents which contain information related to the connected components found.

run

public void run()

Executes the algorithm.

Overrides:

run in class StrongConnectivity

addAllEdgeTypes

public void addAllEdgeTypes(EdgesDirection dir)

Allows connectivity through all edge types of the graph.

Overrides:

addAllEdgeTypes in class StrongConnectivity

Parameters:

dir - [in] Edge direction.

excludeEdges

public void excludeEdges(Objects edges)

Set which edges can't be used.

This will replace any previously specified set of excluded edges. Should only be used to exclude the usage of specific edges from allowed edge types because it's less efficient than not allowing an edge type.

Overrides:

excludeEdges in class StrongConnectivity

Parameters:

edges - [in] A set of edge identifiers that must be kept intact until the destruction of the class.

addNodeType

public void addNodeType(int t)

Allows connectivity through nodes of the given type.

Overrides:

addNodeType in class StrongConnectivity

Parameters:

t - null

setMaterializedAttribute

public void setMaterializedAttribute(java.lang.String attributeName)

Creates a new common attribute type for all node types in the graph in order to store, persistently, the results related to the connected components found while executing this algorithm.

Whenever the user wants to retrieve the results, even when the graph has been closed and opened again, it is only necessary to create a new instance of the class ConnectedComponents indicating the graph and the name of the common attribute type which stores the results. This instance will have all the information related to the connected components found in the moment of the execution of the algorithm that stored this data.

It is possible to run the algorithm without specifying this parameter in order to avoid materializing the results of the execution.

Overrides:

setMaterializedAttribute in class StrongConnectivity

Parameters:

attributeName - [in] The name of the common attribute type for all node types in the graph which will store persistently the results generated by the execution of the algorithm.

addAllNodeTypes

public void addAllNodeTypes()

Allows connectivity through all node types of the graph.

Overrides:

addAllNodeTypes in class StrongConnectivity