org.jgrapht.generate

## Class ComplementGraphGenerator<V,E>

• Type Parameters:
V - vertex type
E - edge type
All Implemented Interfaces:
GraphGenerator<V,E,V>

public class ComplementGraphGenerator<V,E>
extends Object
implements GraphGenerator<V,E,V>
Generator which produces the complement graph of a given input graph. The complement $\overline{G}$ of a graph $G$ consists of the same vertices as $G$, but whose edge set consists of the edges not in $G$.

More formally, let $G = (V, E)$ be a graph and let $K$ consist of all 2-element subsets of $V$. Then $\overline{G} = (V, K \setminus E)$ is the complement of $G$, where $K \setminus E$ is the relative complement of $E$ in $K$. For directed graphs, the complement can be defined in the same way, as a directed graph on the same vertex set, using the set of all 2-element ordered pairs of $V$ in place of the set $K$ in the formula above.

The complement is not defined for multigraphs. If a multigraph is provided as input to this generator, it will be treated as if it is a simple graph.

Since:
Sept 2017
Author:
Joris Kinable
• ### Constructor Summary

Constructors
Constructor and Description
ComplementGraphGenerator(Graph<V,E> graph)
Complement Graph Generator
ComplementGraphGenerator(Graph<V,E> graph, boolean generateSelfLoops)
Complement Graph Generator.
• ### Method Summary

All Methods
Modifier and Type Method and Description
void generateGraph(Graph<V,E> target)
Generates the complement graph.
void generateGraph(Graph<V,E> target, VertexFactory<V> vertexFactory, Map<String,V> resultMap)
Generate a graph structure.
• ### Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
• ### Constructor Detail

• #### ComplementGraphGenerator

public ComplementGraphGenerator(Graph<V,E> graph)
Complement Graph Generator
Parameters:
graph - input graph
• #### ComplementGraphGenerator

public ComplementGraphGenerator(Graph<V,E> graph,
boolean generateSelfLoops)
Complement Graph Generator. If the target graph allows self-loops the complement of $G$ may be defined by adding a self-loop to every vertex that does not have one in $G$. This behavior can be controlled using the boolean generateSelfLoops.
Parameters:
graph - input graph
generateSelfLoops - indicator whether self loops should be generated. If false, no self-loops are generated, independent of whether the target graph supports self-loops.
• ### Method Detail

• #### generateGraph

public void generateGraph(Graph<V,E> target)
Generates the complement graph.
Parameters:
target - receives the generated edges and vertices; if this is non-empty on entry, the result will be a disconnected graph since generated elements will not be connected to existing elements
• #### generateGraph

public void generateGraph(Graph<V,E> target,
VertexFactory<V> vertexFactory,
Map<String,V> resultMap)
Description copied from interface: GraphGenerator
Generate a graph structure. The topology of the generated graph is dependent on the implementation. For graphs in which not all vertices share the same automorphism equivalence class, the generator may produce a labeling indicating the roles played by generated elements. This is the purpose of the resultMap parameter. For example, a generator for a wheel graph would designate a hub vertex. Role names used as keys in resultMap should be declared as public static final Strings by implementation classes.
Specified by:
generateGraph in interface GraphGenerator<V,E,V>
Parameters:
target - receives the generated edges and vertices; if this is non-empty on entry, the result will be a disconnected graph since generated elements will not be connected to existing elements
vertexFactory - called to produce new vertices
resultMap - if non-null, receives implementation-specific mappings from String roles to graph elements (or collections of graph elements)