Sparksee  5.2.0
STSStrongConnectivityGabow Class Reference

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

Inheritance diagram for STSStrongConnectivityGabow:
Inheritance graph
Collaboration diagram for STSStrongConnectivityGabow:
Collaboration graph

Instance Methods

(id) - initWithSession:
 Creates a new instance of StrongConnectivityGabow.
 
(void) - run
 Executes the algorithm.
 
(void) - addEdgeType:dir:
 Allows connectivity through edges of the given type.
 
(void) - addAllEdgeTypes:
 Allows connectivity through all edge types of the graph.
 
(void) - addNodeType:
 Allows connectivity through nodes of the given type.
 
(void) - addAllNodeTypes
 Allows connectivity through all node types of the graph.
 
(void) - excludeNodes:
 Set which nodes can't be used.
 
(void) - excludeEdges:
 Set which edges can't be used.
 
(STSConnectedComponents *) - getConnectedComponents
 Returns the results generated by the execution of the algorithm.
 
(void) - setMaterializedAttribute:
 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.
 
(void) - close
 Closes the Connectivity instance.
 
(BOOL) - isClosed
 Check if the Connectivity instance is closed.
 

Detailed Description

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

Method Documentation

- (void) addAllEdgeTypes: (enum STSEdgesDirection)  dir

Allows connectivity through all edge types of the graph.

Parameters
dir[in] Edge direction.
- (void) addEdgeType: (int)  type
dir: (enum STSEdgesDirection)  dir 

Allows connectivity through edges of the given type.

Parameters
type[in] Edge type.
dir[in] Edge direction.
- (void) addNodeType: (int)  t

Allows connectivity through nodes of the given type.

Parameters
tnull
- (void) close

Closes the Connectivity instance.

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

- (void) excludeEdges: (STSObjects *)  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.

Parameters
edges[in] A set of edge identifiers that must be kept intact until the destruction of the class.
- (void) excludeNodes: (STSObjects *)  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.

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

Returns
Returns an instance of the class ConnectedComponents which contain information related to the connected components found.
- (id) initWithSession: (STSSession *)  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
- (void) setMaterializedAttribute: (NSString *)  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.

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.

The documentation for this class was generated from the following file: