sparksee.StrongConnectivityGabow Class Reference

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

Inheritance diagram for sparksee.StrongConnectivityGabow:

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Collaboration diagram for sparksee.StrongConnectivityGabow:

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List of all members.

Public Member Functions

def add_edge_type
 Allows connectivity through edges of the given type.
def add_all_node_types
 Allows connectivity through all node types of the graph.
def exclude_nodes
 Set which nodes can't be used.
def run
 Executes the algorithm.
def add_node_type
 Allows connectivity through nodes of the given type.
def add_all_edge_types
 Allows connectivity through all edge types of the graph.
def __init__
 Creates a new instance of StrongConnectivityGabow.
def set_materialized_attribute
 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.
def exclude_edges
 Set which edges can't be used.
def get_connected_components
 Returns the results generated by the execution of the algorithm.
def is_closed
 Gets if Connectivity has been closed or not.
def close
 Closes the Connectivity instance.


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

Member Function Documentation

def sparksee.StrongConnectivityGabow.add_edge_type (   self,
  t,
  d 
)

Allows connectivity through edges of the given type.

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

Reimplemented from sparksee.StrongConnectivity.

def sparksee.StrongConnectivityGabow.exclude_nodes (   self,
  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.

Reimplemented from sparksee.StrongConnectivity.

def sparksee.StrongConnectivityGabow.add_node_type (   self,
  t 
)

Allows connectivity through nodes of the given type.

Parameters:
t null

Reimplemented from sparksee.StrongConnectivity.

def sparksee.StrongConnectivityGabow.add_all_edge_types (   self,
  d 
)

Allows connectivity through all edge types of the graph.

Parameters:
d [in] Edge direction.

Reimplemented from sparksee.StrongConnectivity.

def sparksee.StrongConnectivityGabow.__init__ (   self,
  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

def sparksee.StrongConnectivityGabow.set_materialized_attribute (   self,
  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.

Reimplemented from sparksee.StrongConnectivity.

def sparksee.StrongConnectivityGabow.exclude_edges (   self,
  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.

Reimplemented from sparksee.StrongConnectivity.

def sparksee.StrongConnectivityGabow.get_connected_components (   self  ) 

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.

Reimplemented from sparksee.StrongConnectivity.

def sparksee.Connectivity.is_closed (   self  )  [inherited]

Gets if Connectivity has been closed or not.

See also:
close()
Returns:
TRUE if the Connectivity instance has been closed, FALSE otherwise.

def sparksee.Connectivity.close (   self  )  [inherited]

Closes the Connectivity instance.

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


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