API Docs for: 1.3.12
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Hypergraph Class

A hypergraph, consisting of a set of vertices of type V and a set of hyperedges of type E which connect the vertices. This is the base interface for all JUNG graph types.

This interface permits, but does not enforce, any of the following common variations of graphs:

  • hyperedges (edges which connect a set of vertices of any size)
  • edges (these have have exactly two endpoints, which may or may not be distinct)
  • self-loops (edges which connect exactly one vertex)
  • directed and undirected edges
  • vertices and edges with attributes (for example, weighted edges)
  • vertices and edges with different constraints or properties (for example, bipartite or multimodal graphs)
  • parallel edges (multiple edges which connect a single set of vertices)
  • internal representations as matrices or as adjacency lists or adjacency maps
Extensions or implementations of this interface may enforce or disallow any or all of these variations.

Notes:

  • The collections returned by Hypergraph instances should be treated in general as if read-only. While they are not contractually guaranteed (or required) to be immutable, this interface does not define the outcome if they are mutated. Mutations should be done via {add,remove}{Edge,Vertex}, or in the constructor.

Methods

addHyperEdge

(
  • edge
  • vertices
)

Adds edge to this graph. Fails under the following circumstances:

  • edge is already an element of the graph
  • either edge or vertices is null
  • vertices has the wrong number of vertices for the graph type
  • vertices are already connected by another edge in this graph, and this graph does not accept parallel edges

Parameters:

  • edge Object
  • vertices Object

Returns:

true if the add is successful, and false otherwise

Throws:

IllegalArgumentException if edge or vertices is null, or if a different vertex set in this graph is already connected by edge, or if vertices are not a legal vertex set for edge

addVertex

(
  • vertex
)

Adds vertex to this graph. Fails if vertex is null or already in the graph.

Parameters:

  • vertex Object

    the vertex to add

Returns:

true if the add is successful, and false otherwise

Throws:

IllegalArgumentException if vertex is null

containsEdge

(
  • edge
)

Returns true if this graph's edge collection contains edge. Equivalent to getEdges().contains(edge).

Parameters:

  • edge Object

    the edge whose presence is being queried

Returns:

true iff this graph contains an edge edge

containsVertex

(
  • vertex
)

Returns true if this graph's vertex collection contains vertex. Equivalent to getVertices().contains(vertex).

Parameters:

  • vertex Object

    the vertex whose presence is being queried

Returns:

true iff this graph contains a vertex vertex

degree

(
  • vertex
)

Returns the number of edges incident to vertex. Special cases of interest:

  • Incident self-loops are counted once.
  • If there is only one edge that connects this vertex to each of its neighbors (and vice versa), then the value returned will also be equal to the number of neighbors that this vertex has (that is, the output of getNeighborCount).
  • If the graph is directed, then the value returned will be the sum of this vertex's indegree (the number of edges whose destination is this vertex) and its outdegree (the number of edges whose source is this vertex), minus the number of incident self-loops (to avoid double-counting).

Equivalent to getIncidentEdges(vertex).size().

Parameters:

  • vertex Object

    the vertex whose degree is to be returned

Returns:

the degree of this node

findEdge

(
  • v1
  • v2
)

Returns an edge that connects this vertex to v. If this edge is not uniquely defined (that is, if the graph contains more than one edge connecting v1 to v2), any of these edges may be returned. findEdgeSet(v1, v2) may be used to return all such edges. Returns null if either of the following is true:

  • v2 is not connected to v1
  • either v1 or v2 are not present in this graph

Note: for purposes of this method, v1 is only considered to be connected to v2 via a given directed edge e if v1 == e.getSource() && v2 == e.getDest() evaluates to true. (v1 and v2 are connected by an undirected edge u if u is incident to both v1 and v2.)

Parameters:

  • v1 Object

    between this

  • v2 Object

    and that

Returns:

an edge that connects v1 to v2, or null if no such edge exists (or either vertex is not present)

findEdgeSet

(
  • v1
  • v2
)

Returns all edges that connects this vertex to v. If this edge is not uniquely defined (that is, if the graph contains more than one edge connecting v1 to v2), any of these edges may be returned. findEdgeSet(v1, v2) may be used to return all such edges. Returns null if v2 is not connected to v1.
Returns an empty collection if either v1 or v2 are not present in this graph.

Note: for purposes of this method, v1 is only considered to be connected to v2 via a given directed edge d if v1 == d.getSource() && v2 == d.getDest() evaluates to true. (v1 and v2 are connected by an undirected edge u if u is incident to both v1 and v2.)

Parameters:

  • v1 Object

    between this

  • v2 Object

    and that

Returns:

a collection containing all edges that connect v1 to v2, or null if either vertex is not present

getDefaultEdgeType

()

Returns the default edge type for this graph.

Returns:

the default edge type for this graph

getDest

(
  • directed_edge
)

If directed_edge is a directed edge in this graph, returns the destination; otherwise returns null. The destination of a directed edge d is defined to be the vertex incident to d for which d is an incoming edge. directed_edge is guaranteed to be a directed edge if its EdgeType is DIRECTED.

Parameters:

  • directed_edge Object

Returns:

the destination of directed_edge if it is a directed edge in this graph, or null otherwise

getEdgeCount

()

Returns the number of edges in this graph.

Returns:

the number of edges in this graph

getEdgeCountOfType

(
  • edge_type
)

Returns the number of edges of type edge_type in this graph.

Parameters:

  • edge_type Object

    the type of edge for which the count is to be returned

Returns:

the number of edges of type edge_type in this graph

getEdges

()

Returns a view of all edges in this graph. In general, this obeys the Array contract, and therefore makes no guarantees about the ordering of the vertices within the set.

Returns:

a Array view of all edges in this graph

getEdgesOfType

(
  • edge_type
)

Returns the collection of edges in this graph which are of type edge_type.

Parameters:

  • edge_type Object

    the type of edges to be returned

Returns:

the collection of edges which are of type edge_type, or null if the graph does not accept edges of this type

getEdgeType

(
  • edge
)

Returns the edge type of edge in this graph.

Parameters:

  • edge Object

Returns:

the EdgeType of edge, or null if edge has no defined type

getIncidentCount

(
  • edge
)

Returns the number of vertices that are incident to edge. For hyperedges, this can be any nonnegative integer; for edges this must be 2 (or 1 if self-loops are permitted).

Equivalent to getIncidentVertices(edge).size().

Parameters:

  • edge Object

    the edge whose incident vertex count is to be returned

Returns:

the number of vertices that are incident to edge.

getIncidentEdges

(
  • vertex
)

Returns the collection of edges in this graph which are connected to vertex.

Parameters:

  • vertex Object

    the vertex whose incident edges are to be returned

Returns:

the collection of edges which are connected to vertex, or null if vertex is not present

getIncidentVertices

(
  • edge
)

Returns the collection of vertices in this graph which are connected to edge. Note that for some graph types there are guarantees about the size of this collection (i.e., some graphs contain edges that have exactly two endpoints, which may or may not be distinct). Implementations for those graph types may provide alternate methods that provide more convenient access to the vertices.

Parameters:

  • edge Object

    the edge whose incident vertices are to be returned

Returns:

the collection of vertices which are connected to edge, or null if edge is not present

getInEdges

(
  • vertex
)

Returns a Array view of the incoming edges incident to vertex in this graph.

Parameters:

  • vertex Object

    the vertex whose incoming edges are to be returned

Returns:

a Array view of the incoming edges incident to vertex in this graph

getNeighborCount

(
  • vertex
)

Returns the number of vertices that are adjacent to vertex (that is, the number of vertices that are incident to edges in vertex's incident edge set).

Equivalent to getNeighbors(vertex).size().

Parameters:

  • vertex Object

    the vertex whose neighbor count is to be returned

Returns:

the number of neighboring vertices

getNeighbors

(
  • vertex
)

Returns the collection of vertices which are connected to vertex via any edges in this graph. If vertex is connected to itself with a self-loop, then it will be included in the collection returned.

Parameters:

  • vertex Object

    the vertex whose neighbors are to be returned

Returns:

the collection of vertices which are connected to vertex, or null if vertex is not present

getOutEdges

(
  • vertex
)

Returns a Array view of the outgoing edges incident to vertex in this graph.

Parameters:

  • vertex Object

    the vertex whose outgoing edges are to be returned

Returns:

a Array view of the outgoing edges incident to vertex in this graph

getPredecessors

(
  • vertex
)

Returns a Array view of the predecessors of vertex in this graph. A predecessor of vertex is defined as a vertex v which is connected to vertex by an edge e, where e is an outgoing edge of v and an incoming edge of vertex.

Parameters:

  • vertex Object

    the vertex whose predecessors are to be returned

Returns:

a Array view of the predecessors of vertex in this graph

getSource

(
  • directed_edge
)

If directed_edge is a directed edge in this graph, returns the source; otherwise returns null. The source of a directed edge d is defined to be the vertex for which d is an outgoing edge. directed_edge is guaranteed to be a directed edge if its EdgeType is DIRECTED.

Parameters:

  • directed_edge Object

Returns:

the source of directed_edge if it is a directed edge in this graph, or null otherwise

getSuccessors

(
  • vertex
)

Returns a Array view of the successors of vertex in this graph. A successor of vertex is defined as a vertex v which is connected to vertex by an edge e, where e is an incoming edge of v and an outgoing edge of vertex.

Parameters:

  • vertex Object

    the vertex whose predecessors are to be returned

Returns:

a Array view of the successors of vertex in this graph

getVertexCount

()

Returns the number of vertices in this graph.

Returns:

the number of vertices in this graph

getVerticies

()

Returns a view of all vertices in this graph. In general, this obeys the Array contract, and therefore makes no guarantees about the ordering of the vertices within the set.

Returns:

a Array view of all vertices in this graph

inDegree

(
  • vertex
)

Returns the number of incoming edges incident to vertex. Equivalent to getInEdges(vertex).size().

Parameters:

  • vertex Object

    the vertex whose indegree is to be calculated

Returns:

the number of incoming edges incident to vertex

isIncident

(
  • vertex
  • edge
)

Returns true if vertex and edge are incident to each other. Equivalent to getIncidentEdges(vertex).contains(edge) and to getIncidentVertices(edge).contains(vertex).

Parameters:

  • vertex Object
  • edge Object

Returns:

true if vertex and edge are incident to each other

isNeighbor

(
  • v1
  • v2
)

Returns true if v1 and v2 share an incident edge. Equivalent to getNeighbors(v1).contains(v2).

Parameters:

  • v1 Object

    the first vertex to test

  • v2 Object

    the second vertex to test

Returns:

true if v1 and v2 share an incident edge

outDegree

(
  • vertex
)

Returns the number of outgoing edges incident to vertex. Equivalent to getOutEdges(vertex).size().

Parameters:

  • vertex Object

    the vertex whose outdegree is to be calculated

Returns:

the number of outgoing edges incident to vertex

removeEdge

(
  • edge
)

Removes edge from this graph. Fails if edge is null, or is otherwise not an element of this graph.

Parameters:

  • edge Object

    the edge to remove

Returns:

true if the removal is successful, false otherwise

removeVertex

(
  • vertex
)

Removes vertex from this graph. As a side effect, removes any edges e incident to vertex if the removal of vertex would cause e to be incident to an illegal number of vertices. (Thus, for example, incident hyperedges are not removed, but incident edges--which must be connected to a vertex at both endpoints--are removed.)

Fails under the following circumstances:

  • vertex is not an element of this graph
  • vertex is null

Parameters:

  • vertex Object

    the vertex to remove

Returns:

true if the removal is successful, false otherwise