org.jgrapht

Class GraphTests

java.lang.Object

org.jgrapht.GraphTests

public abstract class GraphTests
extends Object

A collection of utilities to test for various graph properties.

Author:

Barak Naveh, Dimitrios Michail

Constructor Summary

Constructors

Constructor and Description
GraphTests()

Method Summary

Modifier and Type	Method and Description
static <V,E> boolean	isBipartite(Graph<V,E> graph) Test whether a graph is bipartite.
static <V,E> boolean	isBipartitePartition(Graph<V,E> graph, Set<? extends V> firstPartition, Set<? extends V> secondPartition) Test whether a partition of the vertices into two sets is a bipartite partition.
static <V,E> boolean	isComplete(Graph<V,E> graph) Test whether a graph is complete.
static <V,E> boolean	isConnected(UndirectedGraph<V,E> graph) Test whether an undirected graph is connected.
static <V,E> boolean	isEmpty(Graph<V,E> graph) Test whether a graph is empty.
static <V,E> boolean	isEulerian(Graph<V,E> graph) Test whether a graph is Eulerian.
static <V,E> boolean	isSimple(Graph<V,E> graph) Check if a graph is simple.
static <V,E> boolean	isStronglyConnected(DirectedGraph<V,E> graph) Test whether a directed graph is strongly connected.
static <V,E> boolean	isTree(UndirectedGraph<V,E> graph) Test whether an undirected graph is a tree.
static <V,E> boolean	isWeaklyConnected(DirectedGraph<V,E> graph) Test whether a directed graph is weakly connected.

Methods inherited from class java.lang.Object

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

Constructor Detail

GraphTests

public GraphTests()

Method Detail

isEmpty

public static <V,E> boolean isEmpty(Graph<V,E> graph)

Test whether a graph is empty. An empty graph on n nodes consists of n isolated vertices with no edges.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is empty, false otherwise

isSimple

public static <V,E> boolean isSimple(Graph<V,E> graph)

Check if a graph is simple. A graph is simple if it has no self-loops and multiple edges.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - a graph

Returns:

true if a graph is simple, false otherwise

isComplete

public static <V,E> boolean isComplete(Graph<V,E> graph)

Test whether a graph is complete. A complete undirected graph is a simple graph in which every pair of distinct vertices is connected by a unique edge. A complete directed graph is a directed graph in which every pair of distinct vertices is connected by a pair of unique edges (one in each direction).

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is complete, false otherwise

isConnected

public static <V,E> boolean isConnected(UndirectedGraph<V,E> graph)

Test whether an undirected graph is connected.

This method does not performing any caching, instead recomputes everything from scratch. In case more control is required use ConnectivityInspector directly.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is connected, false otherwise

See Also:

ConnectivityInspector

isWeaklyConnected

public static <V,E> boolean isWeaklyConnected(DirectedGraph<V,E> graph)

Test whether a directed graph is weakly connected.

This method does not performing any caching, instead recomputes everything from scratch. In case more control is required use ConnectivityInspector directly.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is weakly connected, false otherwise

See Also:

ConnectivityInspector

isStronglyConnected

public static <V,E> boolean isStronglyConnected(DirectedGraph<V,E> graph)

Test whether a directed graph is strongly connected.

This method does not performing any caching, instead recomputes everything from scratch. In case more control is required use KosarajuStrongConnectivityInspector directly.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is strongly connected, false otherwise

See Also:

KosarajuStrongConnectivityInspector

isTree

public static <V,E> boolean isTree(UndirectedGraph<V,E> graph)

Test whether an undirected graph is a tree.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is tree, false otherwise

isBipartite

public static <V,E> boolean isBipartite(Graph<V,E> graph)

Test whether a graph is bipartite.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is bipartite, false otherwise

isBipartitePartition

public static <V,E> boolean isBipartitePartition(Graph<V,E> graph,
                                                 Set<? extends V> firstPartition,
                                                 Set<? extends V> secondPartition)

Test whether a partition of the vertices into two sets is a bipartite partition.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

firstPartition - the first vertices partition

secondPartition - the second vertices partition

Returns:

true if the partition is a bipartite partition, false otherwise

isEulerian

public static <V,E> boolean isEulerian(Graph<V,E> graph)

Test whether a graph is Eulerian. An undirected graph is Eulerian if it is connected and each vertex has an even degree. A directed graph is Eulerian if it is strongly connected and each vertex has the same incoming and outgoing degree. Test whether a graph is Eulerian. An Eulerian graph is a graph containing an Eulerian cycle.

Type Parameters:

V - the graph vertex type

E - the graph edge type

Parameters:

graph - the input graph

Returns:

true if the graph is Eulerian, false otherwise

See Also:

HierholzerEulerianCycle.isEulerian(Graph)