StrongConnectivityGabow Class Reference
[Algorithms]

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

Inheritance diagram for StrongConnectivityGabow:

Inheritance graph
Collaboration diagram for StrongConnectivityGabow:

Collaboration graph

List of all members.

Public Member Functions

 StrongConnectivityGabow (dex::gdb::Session &s)
 Creates a new instance of StrongConnectivityGabow.
virtual ~StrongConnectivityGabow ()
 Destructor.
void Run ()
 Executes the algorithm.
virtual void AddEdgeType (dex::gdb::type_t t, dex::gdb::EdgesDirection d)
 Allows connectivity through edges of the given type.
virtual void AddAllEdgeTypes (dex::gdb::EdgesDirection d)
 Allows connectivity through all edge types of the graph.
virtual void AddNodeType (dex::gdb::type_t t)
 Allows connectivity through nodes of the given type.
virtual void AddAllNodeTypes ()
 Allows connectivity through all node types of the graph.
virtual void ExcludeNodes (dex::gdb::Objects &nodes)
 Set which nodes can't be used.
virtual void ExcludeEdges (dex::gdb::Objects &edges)
 Set which edges can't be used.
ConnectedComponentsGetConnectedComponents ()
 Returns the results generated by the execution of the algorithm.
void SetMaterializedAttribute (const std::wstring &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.

Protected Types

typedef std::map
< dex::gdb::type_t,
dex::gdb::EdgesDirection
EdgeTypes_t
 A type definition to store allowed edge types.
typedef std::vector
< dex::gdb::type_t
NodeTypes_t
 A type definition to store allowed node types.

Protected Member Functions

void AssertAddedEdges ()
 Check that edges had been added.
void AssertAddedNodes ()
 Check that nodes had been added.
void AssertNotComputed ()
 Check that the connectivity had not been calculated yet.
void SetConnectedComponent (dex::gdb::oid_t idNode)
 Assigns the current component to the given node.
void SetNodesNotVisited ()
 Set all the selected nodes in nodesNotVisited.
void AssertNotComponentAttribute (const std::wstring &attributeName)
 Check that the given attribute name is not already in use.
void AssertComputed ()
 Check that the connectivity had been calculated.
void AssertEdgeType (dex::gdb::type_t edgetype)
 Check that the given edge type is valid.
void AssertNodeType (dex::gdb::type_t nodetype)
 Check that the given node type is valid.
void CreateGlobalPersistentAttribute (const std::wstring &attributeName)
 Set a new persistent global attribute to store the connectivity information.
void CreateGlobalTransientAttribute ()
 Set a new temporary global attribute to store the connectivity information.
void RemoveGlobalAttribute ()
 Removes the global attribute where the connectivity information is stored.
dex::gdb::bool_t IsNodeTypeAllowed (dex::gdb::oid_t nodeId)
 Check if the given node has an allowed type.
dex::gdb::bool_t IsNodeExcluded (dex::gdb::oid_t node)
 Check if the given node is forbidden.
dex::gdb::bool_t IsEdgeExcluded (dex::gdb::oid_t edge)
 Check if the given edge is forbidden.

Protected Attributes

dex::gdb::Session * sess
 Session.
dex::gdb::Graph * graph
 Graph.
EdgeTypes_t edgeTypes
 Allowed edge types.
std::vector< dex::gdb::type_tnodeTypes
 Allowed node types.
dex::gdb::attr_t attrComponent
 common attribute where the connected component information is stored.
std::wstring attrComponentName
 name of the common attribute where the connected component information is stored.
dex::gdb::int64_t actualComponent
 Current component identifier.
dex::gdb::Objects * nodesNotVisited
 Identifiers of the nodes not visited.
dex::gdb::bool_t matResults
 Materialized results.
dex::gdb::bool_t computed
 True if the connectivity has been calculated.
dex::gdb::Objects * excludedNodes
 The set of excluded nodes.
dex::gdb::Objects * excludedEdges
 The set of excluded edges.
ConnectedComponentsccs
 The calculated connectivity information.

Classes

class  InfoNode


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. Those restrictions are:

(i) The set of edge types which will be navigated through while traversing the graph. The method is AddEdgeType for adding one edge type and AddAllEdgeTypes for adding all edge types with a specified direction.

(ii) The set of node types which will be navigated through while traversing the graph. The method is AddNodeType for adding one node type and AddAllNodeTypes for adding all node types.

For each instance of this class, it is only allowed to run the algorithm once.

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

NOTE: It is required to indicate the set of edge types and node types before running this algorithm.

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

Constructor & Destructor Documentation

StrongConnectivityGabow::StrongConnectivityGabow ( dex::gdb::Session &  s  ) 

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:
s [in] Session to get the graph from and calculate the connectivity


Member Function Documentation

virtual void StrongConnectivity::AddEdgeType ( dex::gdb::type_t  t,
dex::gdb::EdgesDirection  d 
) [virtual, inherited]

Allows connectivity through edges of the given type.

Parameters:
t [in] Edge type.
d [in] Edge direction.

Reimplemented from Connectivity.

virtual void StrongConnectivity::AddAllEdgeTypes ( dex::gdb::EdgesDirection  d  )  [virtual, inherited]

Allows connectivity through all edge types of the graph.

Parameters:
d [in] Edge direction.

Reimplemented from Connectivity.

virtual void Connectivity::ExcludeNodes ( dex::gdb::Objects &  nodes  )  [virtual, inherited]

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.

virtual void Connectivity::ExcludeEdges ( dex::gdb::Objects &  edges  )  [virtual, inherited]

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.

ConnectedComponents* Connectivity::GetConnectedComponents (  )  [inherited]

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.

void Connectivity::SetMaterializedAttribute ( const std::wstring &  attributeName  )  [inherited]

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.

void Connectivity::SetNodesNotVisited (  )  [protected, inherited]

Set all the selected nodes in nodesNotVisited.

That's all the nodes of the allowed node types but not the excluded ones.


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

Generated on Mon Oct 15 14:40:47 2012 for Dex by  doxygen 1.5.6