org.graphstream.algorithm.measure
Class ConnectivityMeasure

java.lang.Object
  org.graphstream.algorithm.measure.ConnectivityMeasure

public class ConnectivityMeasure
extends Object

Get the vertex-connectivity of a graph. A graph is said to be k-vertex-connected (or k-connected) if the graph remains connected when you delete fewer than k vertices from the graph (from Wikipedia).

Nested Class Summary

static class	ConnectivityMeasure.EdgeConnectivityMeasure
static class	ConnectivityMeasure.VertexConnectivityMeasure

Constructor Summary

ConnectivityMeasure()

Method Summary

static int	getEdgeConnectivity(org.graphstream.graph.Graph g) Get the edge-connectivity k of a graph such that there is a k-tuple of edges whose removal disconnects the graph.
static org.graphstream.graph.Edge[]	getKDisconnectingEdgeTuple(org.graphstream.graph.Graph g, int k) Get a k-tuple of edges whose removal causes the disconnection of the graph.
static org.graphstream.graph.Node[]	getKDisconnectingNodeTuple(org.graphstream.graph.Graph g, int k) Get a k-tuple of nodes whose removal causes the disconnection of the graph.
static int	getVertexConnectivity(org.graphstream.graph.Graph g) Get the vertex-connectivity k of a graph such that there is a k-tuple of nodes whose removal disconnects the graph.
static boolean	isKEdgeConnected(org.graphstream.graph.Graph g, int k) Check if a graph is k-edge-connected, ie. there is no (k-1)-edge-tuple such that the removal of these edges leads to disconnect the graph.
static boolean	isKVertexConnected(org.graphstream.graph.Graph g, int k) Check if a graph is k-vertex-connected, ie. there is no (k-1)-node-tuple such that the removal of these nodes leads to disconnect the graph.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConnectivityMeasure

public ConnectivityMeasure()

Method Detail

getVertexConnectivity

public static int getVertexConnectivity(org.graphstream.graph.Graph g)

Get the vertex-connectivity k of a graph such that there is a k-tuple of nodes whose removal disconnects the graph.

Parameters:

g - the graph

Returns:

vertex connectivity

getEdgeConnectivity

public static int getEdgeConnectivity(org.graphstream.graph.Graph g)

Get the edge-connectivity k of a graph such that there is a k-tuple of edges whose removal disconnects the graph. This uses the Ford-Fulkerson algorithm to compute maximum flows in the graph. A simple algorithm would, for every pair (u,v), determine the maximum flow from u to v with the capacity of all edges in G set to 1 for both directions. A graph is k-edge-connected if and only if the maximum flow from u to v is at least k for any pair (u,v), so k is the least u-v-flow among all (u,v). Source Wikipedia.

Parameters:

g - the graph

Returns:

edge connectivity

isKVertexConnected

public static boolean isKVertexConnected(org.graphstream.graph.Graph g,
                                         int k)

Check if a graph is k-vertex-connected, ie. there is no (k-1)-node-tuple such that the removal of these nodes leads to disconnect the graph.

Parameters:

g - the graph

k - connectivity being checked

Returns:

true if g is k-vertex-connected

isKEdgeConnected

public static boolean isKEdgeConnected(org.graphstream.graph.Graph g,
                                       int k)

Check if a graph is k-edge-connected, ie. there is no (k-1)-edge-tuple such that the removal of these edges leads to disconnect the graph.

Parameters:

g - the graph

k - connectivity being checked

Returns:

true if g is k-edge-connected

getKDisconnectingNodeTuple

public static org.graphstream.graph.Node[] getKDisconnectingNodeTuple(org.graphstream.graph.Graph g,
                                                                      int k)

Get a k-tuple of nodes whose removal causes the disconnection of the graph.

Parameters:

g - the graph

k - max size of the required tuple

Returns:

a k-tuple of nodes or null if graph is (k+1)-vertex-connected

getKDisconnectingEdgeTuple

public static org.graphstream.graph.Edge[] getKDisconnectingEdgeTuple(org.graphstream.graph.Graph g,
                                                                      int k)

Get a k-tuple of edges whose removal causes the disconnection of the graph.

Parameters:

g - the graph

k - max size of the required tuple

Returns:

a k-tuple of edges or null if graph is (k+1)-edge-connected