org.jgrapht.traverse

Class DegeneracyOrderingIterator<V,E>

java.lang.Object

org.jgrapht.traverse.AbstractGraphIterator<V,E>

org.jgrapht.traverse.DegeneracyOrderingIterator<V,E>

Type Parameters:

V - the graph vertex type

E - the graph edge type

All Implemented Interfaces:

Iterator<V>, GraphIterator<V,E>

public class DegeneracyOrderingIterator<V,E>
extends AbstractGraphIterator<V,E>

A degeneracy ordering iterator.

The degeneracy of a graph $G $is the smallest value d such that every nonempty subgraph of $G$ contains a vertex of degree at most $d.$ If a graph has degeneracy $d$, then it has a degeneracy ordering, an ordering such that each vertex has $d$ or fewer neighbors that come later in the ordering.

The iterator crosses components but does not track them, it only tracks visited vertices.

The iterator treats the input graph as undirected even if the graph is directed. Moreover, it completely ignores self-loops, meaning that it operates as if self-loops do not contribute to the degree of a vertex.

Since:

February, 2017

Author:

Dimitrios Michail

Field Summary

Fields inherited from class org.jgrapht.traverse.AbstractGraphIterator

crossComponentTraversal, graph, nListeners, reusableEdgeEvent, reusableVertexEvent, reuseEvents

Constructor Summary

Constructors

Constructor and Description
DegeneracyOrderingIterator(Graph<V,E> graph) Constructor

Method Summary

Modifier and Type	Method and Description
boolean	hasNext()
boolean	isCrossComponentTraversal() Test whether this iterator is set to traverse the graph across connected components.
V	next()
void	setCrossComponentTraversal(boolean crossComponentTraversal) Sets the cross component traversal flag - indicates whether to traverse the graph across connected components.

Methods inherited from class org.jgrapht.traverse.AbstractGraphIterator

addTraversalListener, createEdgeTraversalEvent, createVertexTraversalEvent, fireConnectedComponentFinished, fireConnectedComponentStarted, fireEdgeTraversed, fireVertexFinished, fireVertexTraversed, getGraph, isReuseEvents, remove, removeTraversalListener, setReuseEvents

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

DegeneracyOrderingIterator

public DegeneracyOrderingIterator(Graph<V,E> graph)

Constructor

Parameters:

graph - the graph to be iterated

Method Detail

isCrossComponentTraversal

public boolean isCrossComponentTraversal()

Test whether this iterator is set to traverse the graph across connected components. Always returns true since the iterator does not care about components.

Specified by:

isCrossComponentTraversal in interface GraphIterator<V,E>

Overrides:

isCrossComponentTraversal in class AbstractGraphIterator<V,E>

Returns:

true if traverses across connected components, otherwise false.

setCrossComponentTraversal

public void setCrossComponentTraversal(boolean crossComponentTraversal)

Sets the cross component traversal flag - indicates whether to traverse the graph across connected components. Trying to disable the cross components nature of this iterator will result into throwing a IllegalArgumentException.

Overrides:

setCrossComponentTraversal in class AbstractGraphIterator<V,E>

Parameters:

crossComponentTraversal - if true traverses across connected components.

hasNext

public boolean hasNext()

next

public V next()