cn.jimmiez.pcu.common.graph

类 Graphs

java.lang.Object

cn.jimmiez.pcu.common.graph.Graphs

public class Graphs
extends Object

This class provides some static methods for constructing a graph from matrix, operating on graph.

构造器概要

构造器

构造器和说明
Graphs()

方法概要

限定符和类型	方法和说明
static List<List<Integer>>	connectedComponents(BaseGraph graph) obtain connected components of a **UNDIRECTED GRAPH**.
static boolean	containsCycle(BaseGraph graph) determine if a graph contains cycles.
static int	edgesCountOf(BaseGraph graph) compute the number of edges in a graph.
static BaseGraph	empty() construct a graph with no vertex and edge
static BaseGraph	fullConnectedGraph(List<javax.vecmath.Point3d> vertices, boolean isDirected)
static BaseGraph	graph(double[][] edges, boolean directed) construct a directed graph from given matrix
static BaseGraph	knnGraph(List<javax.vecmath.Point3d> vertices, List<int[]> knnIndices) construct k-nearest-neighbor graph
static UndirectedGraph	minimalSpanningTree(BaseGraph graph) Construct a minimal spanning tree from a graph using Prim algorithm.
static BaseGraph	subGraph(BaseGraph graph, Set<Integer> vertices) get a graph where the vertices is a sub-set of another graph

从类继承的方法 java.lang.Object

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

构造器详细资料

Graphs

public Graphs()

方法详细资料

connectedComponents

public static List<List<Integer>> connectedComponents(BaseGraph graph)

obtain connected components of a **UNDIRECTED GRAPH**.

参数:

graph - an undirected graph

返回:

return a nullable list, each element in it represents a sub-graph, which is a collection of indices of vertices

containsCycle

public static boolean containsCycle(BaseGraph graph)

determine if a graph contains cycles. self-loop is not regarded as a cycle here. for:

• Directed Graph: a cycle must contains at least two vertices.
• Undirected Graph: a cycle must contains at least three vertices.

参数:

graph - a base graph

返回:

if this graph has a cycle

minimalSpanningTree

public static UndirectedGraph minimalSpanningTree(BaseGraph graph)

Construct a minimal spanning tree from a graph using Prim algorithm.

参数:

graph - an undirected graph

返回:

the spanning tree, may be null

subGraph

public static BaseGraph subGraph(BaseGraph graph,
                                 Set<Integer> vertices)

get a graph where the vertices is a sub-set of another graph

参数:

graph - another graph

vertices - indices of vertices

返回:

the sub-graph

edgesCountOf

public static int edgesCountOf(BaseGraph graph)

compute the number of edges in a graph. e_ij e_ji are seen as two different edges despite the directness.

参数:

graph - a graph

返回:

number of edges(

fullConnectedGraph

public static BaseGraph fullConnectedGraph(List<javax.vecmath.Point3d> vertices,
                                           boolean isDirected)

knnGraph

public static BaseGraph knnGraph(List<javax.vecmath.Point3d> vertices,
                                 List<int[]> knnIndices)

construct k-nearest-neighbor graph

参数:

vertices - the vertices

knnIndices - the k-nearest neighbors of vertices

返回:

a undirected graph

graph

public static BaseGraph graph(double[][] edges,
                              boolean directed)

construct a directed graph from given matrix

参数:

edges - the edges, a matrix

directed - if this graph is a directed graph

返回:

a graph

empty

public static BaseGraph empty()

construct a graph with no vertex and edge

返回:

a undirected graph