org.deeplearning4j.graph.api

Interface IGraph<V,E>

Type Parameters:

V - type for vertex objects

E - type for edge objects

All Known Implementing Classes:

BaseGraph, Graph

public interface IGraph<V,E>

Interface for a IGraph, with objects for each vertex and edge. In the simplest case, edges and vertices may be labelled (i.e., IGraph for example), or may be any arbitrary object (or, null).
IGraph may include directed edges, undirected edges, or a combination of both
Note: Every vertex in the graph has an integer index, in range of 0 to numVertices() inclusive

Method Summary

Modifier and Type	Method and Description
void	addEdge(Edge<E> edge) Add an edge to the graph.
void	addEdge(int from, int to, E value, boolean directed) Convenience method for adding an edge (directed or undirected) to graph
int[]	getConnectedVertexIndices(int vertex) Return an array of indexes of vertices that the specified vertex is connected to. Specifically, for undirected graphs return int[] of all X.vertexID() such that (vertex -- X) exists For directed graphs, return int[] of all X.vertexID() such that (vertex -> X) exists
java.util.List<Vertex<V>>	getConnectedVertices(int vertex) Get a list of all of the vertices that the specified vertex is connected to Specifically, for undirected graphs return list of all X such that (vertex -- X) exists For directed graphs, return list of all X such that (vertex -> X) exists
java.util.List<Edge<E>>	getEdgesOut(int vertex) Returns a list of edges for a vertex with a given index For undirected graphs, returns all edges incident on the vertex For directed graphs, only returns outward directed edges
Vertex<V>	getRandomConnectedVertex(int vertex, java.util.Random rng) Randomly sample a vertex connected to a given vertex.
Vertex<V>	getVertex(int idx) Get a vertex in the graph for a given index
int	getVertexDegree(int vertex) Returns the degree of the vertex. For undirected graphs, this is just the degree. For directed graphs, this returns the outdegree
java.util.List<Vertex<V>>	getVertices(int[] indexes) Get multiple vertices in the graph
java.util.List<Vertex<V>>	getVertices(int from, int to) Get multiple vertices in the graph, with secified indices
int	numVertices() Number of vertices in the graph

Method Detail

numVertices

int numVertices()

Number of vertices in the graph

getVertex

Vertex<V> getVertex(int idx)

Get a vertex in the graph for a given index

Parameters:

idx - integer index of the vertex to get. must be in range 0 to numVertices()

Returns:

vertex

getVertices

java.util.List<Vertex<V>> getVertices(int[] indexes)

Get multiple vertices in the graph

Parameters:

indexes - the indexes of the vertices to retrieve

Returns:

list of vertices

getVertices

java.util.List<Vertex<V>> getVertices(int from,
                                      int to)

Get multiple vertices in the graph, with secified indices

Parameters:

from - first vertex to get, inclusive

to - last vertex to get, inclusive

Returns:

list of vertices

addEdge

void addEdge(Edge<E> edge)

Add an edge to the graph.

addEdge

void addEdge(int from,
             int to,
             E value,
             boolean directed)

Convenience method for adding an edge (directed or undirected) to graph

getEdgesOut

java.util.List<Edge<E>> getEdgesOut(int vertex)

Returns a list of edges for a vertex with a given index For undirected graphs, returns all edges incident on the vertex For directed graphs, only returns outward directed edges

Parameters:

vertex - index of the vertex to

Returns:

list of edges for this vertex

getVertexDegree

int getVertexDegree(int vertex)

Returns the degree of the vertex.
For undirected graphs, this is just the degree.
For directed graphs, this returns the outdegree

Parameters:

vertex - vertex to get degree for

Returns:

vertex degree

getRandomConnectedVertex

Vertex<V> getRandomConnectedVertex(int vertex,
                                   java.util.Random rng)
                            throws NoEdgesException

Randomly sample a vertex connected to a given vertex. Sampling is done uniformly at random. Specifically, returns a random X such that either a directed edge (vertex -> X) exists, or an undirected edge (vertex -- X) exists
Can be used for example to implement a random walk on the graph (specifically: a unweighted random walk)

Parameters:

vertex - vertex to randomly sample from

rng - Random number generator to use

Returns:

A vertex connected to the specified vertex,

Throws:

NoEdgesException - thrown if the specified vertex has no edges, or no outgoing edges (in the case of a directed graph).

getConnectedVertices

java.util.List<Vertex<V>> getConnectedVertices(int vertex)

Get a list of all of the vertices that the specified vertex is connected to
Specifically, for undirected graphs return list of all X such that (vertex -- X) exists
For directed graphs, return list of all X such that (vertex -> X) exists

Parameters:

vertex - Index of the vertex

Returns:

list of vertices that the specified vertex is connected to

getConnectedVertexIndices

int[] getConnectedVertexIndices(int vertex)

Return an array of indexes of vertices that the specified vertex is connected to.
Specifically, for undirected graphs return int[] of all X.vertexID() such that (vertex -- X) exists
For directed graphs, return int[] of all X.vertexID() such that (vertex -> X) exists

Parameters:

vertex - index of the vertex

Returns:

list of vertices that the specified vertex is connected to

See Also:

getConnectedVertices(int)