java.lang.Object

com.jgalgo.graph.Graphs

public class Graphs extends Object

Static methods class for graphs.

Author:: Barak Ugav

Method Summary

Modifier and Type

Method

Description

static <V, E> boolean

containsParallelEdges(Graph<V,E> g)

Check whether a graph contain parallel edges.

static <E> E

randEdge(Graph<?,E> g, Random rand)

Get a random edge from the given graph.

static int

randEdge(IntGraph g, Random rand)

Get a random edge from the given int graph.

static <V> V

randVertex(Graph<V,?> g, Random rand)

Get a random vertex from the given graph.

static int

randVertex(IntGraph g, Random rand)

Get a random vertex from the given int graph.

static <V, E> Set<E>

selfEdges(Graph<V,E> g)

Get a view of all the self edges in a graph.

static IntSet

selfEdges(IntGraph g)

Get a view of all the self edges in an int graph.

static <V, E> Graph<V,E>

subGraph(Graph<V,E> g, Collection<V> vertices)

Create a new graph that is an induced subgraph of the given graph.

static <V, E> Graph<V,E>

subGraph(Graph<V,E> g, Collection<V> vertices, Collection<E> edges)

Create a new graph that is a subgraph of the given graph.

static <V, E> Graph<V,E>

subGraph(Graph<V,E> g, Collection<V> vertices, Collection<E> edges, boolean copyVerticesWeights, boolean copyEdgesWeights)

Create a new graph that is a subgraph of the given graph, with option to copy weights.

static IntGraph

subGraph(IntGraph g, IntCollection vertices, IntCollection edges, boolean copyVerticesWeights, boolean copyEdgesWeights)

Create a new graph that is a subgraph of the given int graph, with option to copy weights.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details
- subGraph
  
  public static <V, E> Graph<V,E> subGraph(Graph<V,E> g, Collection<V> vertices)
  
  Create a new graph that is an induced subgraph of the given graph.
  An induced subgraph of a graph \(G=(V,E)\) is a graph \(G'=(V',E')\) where \(V' \subseteq V\) and \(E' = \{\{u,v\} \mid u,v \in V', \{u,v\} \in E\}\). The created graph will have the same type (directed/undirected) as the given graph. The vertices and edges of the created graph will be a subset of the vertices and edges of the given graph.
  The weights of both vertices and edges will not be copied to the new sub graph. For more flexible sub graph creation, see subGraph(Graph, Collection, Collection, boolean, boolean).
  If g is IntGraph, the returned sub graph is also an IntGraph.
  
  Type Parameters:
  
  V - the vertices type
  
  E - the edges type
  
  Parameters:
  
  g - the graph to create a sub graph from
  
  vertices - the vertices of the sub graph
  
  Returns:
  
  a new graph that is an induced subgraph of the given graph
- subGraph
  
  public static <V, E> Graph<V,E> subGraph(Graph<V,E> g, Collection<V> vertices, Collection<E> edges)
  
  Create a new graph that is a subgraph of the given graph.
  If edges is null, then the created graph will be an induced subgraph of the given graph, namely an induced subgraph of a graph \(G=(V,E)\) is a graph \(G'=(V',E')\) where \(V' \subseteq V\) and \(E' = \{\{u,v\} \mid u,v \in V', \{u,v\} \in E\}\). The behavior is similar to subGraph(Graph, Collection). vertices must not be null in this case.
  If vertices is null, then edges must not be null, and the sub graph will contain all the vertices which are either a source or a target of an edge in edges.
  The created graph will have the same type (directed/undirected) as the given graph. The vertices and edges of the created graph will be a subset of the vertices and edges of the given graph.
  The weights of both vertices and edges will not be copied to the new sub graph. For more flexible sub graph creation, see subGraph(Graph, Collection, Collection, boolean, boolean).
  If g is IntGraph, the returned sub graph is also an IntGraph.
  
  Type Parameters:
  
  V - the vertices type
  
  E - the edges type
  
  Parameters:
  
  g - the graph to create a sub graph from
  
  vertices - the vertices of the sub graph, if null then edges must not be null and the vertices of the sub graph will be all the vertices which are either a source or a target of an edge in edges
  
  edges - the edges of the sub graph, if null then vertices must not be null and the sub graph will be an induced subgraph of the given graph
  
  Returns:
  
  a new graph that is a subgraph of the given graph
  
  Throws:
  
  NullPointerException - if both vertices and edges are null
- subGraph
  
  public static <V, E> Graph<V,E> subGraph(Graph<V,E> g, Collection<V> vertices, Collection<E> edges, boolean copyVerticesWeights, boolean copyEdgesWeights)
  
  Create a new graph that is a subgraph of the given graph, with option to copy weights.
  If edges is null, then the created graph will be an induced subgraph of the given graph, namely an induced subgraph of a graph \(G=(V,E)\) is a graph \(G'=(V',E')\) where \(V' \subseteq V\) and \(E' = \{\{u,v\} \mid u,v \in V', \{u,v\} \in E\}\). The behavior is similar to subGraph(Graph, Collection). vertices must not be null in this case.
  If vertices is null, then edges must not be null, and the sub graph will contain all the vertices which are either a source or a target of an edge in edges.
  The created graph will have the same type (directed/undirected) as the given graph. The vertices and edges of the created graph will be a subset of the vertices and edges of the given graph.
  An additional parameter options for copying the weights of the vertices and edges of the given graph to the new sub graph are provided. If copyVerticesWeights is true, then all the vertices weights of the given graph will be copied to the new sub graph. If copyEdgesWeights is true, then all the edges weights of the given graph will be copied to the new sub graph.
  If g is IntGraph, the returned sub graph is also an IntGraph.
  
  Type Parameters:
  
  V - the vertices type
  
  E - the edges type
  
  Parameters:
  
  g - the graph to create a sub graph from
  
  vertices - the vertices of the sub graph, if null then edges must not be null and the vertices of the sub graph will be all the vertices which are either a source or a target of an edge in edges
  
  edges - the edges of the sub graph, if null then vertices must not be null and the sub graph will be an induced subgraph of the given graph
  
  copyVerticesWeights - if true then all the vertices weights of the given graph will be copied to the new sub graph
  
  copyEdgesWeights - if true then all the edges weights of the given graph will be copied to the new sub graph
  
  Returns:
  
  a new graph that is a subgraph of the given graph
  
  Throws:
  
  NullPointerException - if both vertices and edges are null
- subGraph
  
  public static IntGraph subGraph(IntGraph g, IntCollection vertices, IntCollection edges, boolean copyVerticesWeights, boolean copyEdgesWeights)
  
  Create a new graph that is a subgraph of the given int graph, with option to copy weights.
  If edges is null, then the created graph will be an induced subgraph of the given graph, namely an induced subgraph of a graph \(G=(V,E)\) is a graph \(G'=(V',E')\) where \(V' \subseteq V\) and \(E' = \{\{u,v\} \mid u,v \in V', \{u,v\} \in E\}\).
  If vertices is null, then edges must not be null, and the sub graph will contain all the vertices which are either a source or a target of an edge in edges.
  The created graph will have the same type (directed/undirected) as the given graph. The vertices and edges of the created graph will be a subset of the vertices and edges of the given graph.
  An additional parameter options for copying the weights of the vertices and edges of the given graph to the new sub graph are provided. If copyVerticesWeights is true, then all the vertices weights of the given graph will be copied to the new sub graph. If copyEdgesWeights is true, then all the edges weights of the given graph will be copied to the new sub graph.
  
  Parameters:
  
  g - the graph to create a sub graph from
  
  vertices - the vertices of the sub graph, if null then edges must not be null and the vertices of the sub graph will be all the vertices which are either a source or a target of an edge in edges
  
  edges - the edges of the sub graph, if null then vertices must not be null and the sub graph will be an induced subgraph of the given graph
  
  copyVerticesWeights - if true then all the vertices weights of the given graph will be copied to the new sub graph
  
  copyEdgesWeights - if true then all the edges weights of the given graph will be copied to the new sub graph
  
  Returns:
  
  a new graph that is a subgraph of the given graph
  
  Throws:
  
  NullPointerException - if both vertices and edges are null
- randVertex
  
  public static <V> V randVertex(Graph<V,?> g, Random rand)
  
  Get a random vertex from the given graph.
  
  Type Parameters:
  
  V - the vertices type
  
  Parameters:
  
  g - the graph
  
  rand - the random number generator
  
  Returns:
  
  a random vertex from the given graph
  
  Throws:
  
  IllegalArgumentException - if the graph is contains no vertices
- randVertex
  
  public static int randVertex(IntGraph g, Random rand)
  
  Get a random vertex from the given int graph.
  
  Parameters:
  
  g - the graph
  
  rand - the random number generator
  
  Returns:
  
  a random vertex from the given graph
  
  Throws:
  
  IllegalArgumentException - if the graph is contains no vertices
- randEdge
  
  public static <E> E randEdge(Graph<?,E> g, Random rand)
  
  Get a random edge from the given graph.
  
  Type Parameters:
  
  E - the edges type
  
  Parameters:
  
  g - the graph
  
  rand - the random number generator
  
  Returns:
  
  a random edge from the given graph
  
  Throws:
  
  IllegalArgumentException - if the graph is contains no edges
- randEdge
  
  public static int randEdge(IntGraph g, Random rand)
  
  Get a random edge from the given int graph.
  
  Parameters:
  
  g - the graph
  
  rand - the random number generator
  
  Returns:
  
  a random edge from the given graph
  
  Throws:
  
  IllegalArgumentException - if the graph is contains no edges
- selfEdges
  
  public static <V, E> Set<E> selfEdges(Graph<V,E> g)
  
  Get a view of all the self edges in a graph.
  The returned set is a view, namely it will be updated when the graph is updated.
  
  Type Parameters:
  
  V - the vertices type
  
  E - the edges type
  
  Parameters:
  
  g - a graph
  
  Returns:
  
  a view of all the self edges in the graph
- selfEdges
  
  public static IntSet selfEdges(IntGraph g)
  
  Get a view of all the self edges in an int graph.
  The returned set is a view, namely it will be updated when the graph is updated.
  
  Parameters:
  
  g - an int graph
  
  Returns:
  
  a view of all the self edges in the graph
- containsParallelEdges
  
  public static <V, E> boolean containsParallelEdges(Graph<V,E> g)
  
  Check whether a graph contain parallel edges.
  Two parallel edges are edges that have the same source and target vertices.
  
  Type Parameters:
  
  V - the vertices type
  
  E - the edges type
  
  Parameters:
  
  g - a graph
  
  Returns:
  
  true if the graph contain at least one pair of parallel edges, else false

Class Graphs

Method Summary

Methods inherited from class java.lang.Object

Method Details

subGraph

subGraph

subGraph

subGraph

randVertex

randVertex

randEdge

randEdge

selfEdges

selfEdges

containsParallelEdges