IncidenceGraph

The IncidenceGraph concept provides an interface for efficient access to the out-edges of each vertex in the graph.

Refinement of

Notation

`G`	A type that is a model of IncidenceGraph.
`g`	An object of type `G`.
`e`	An object of type `boost::graph_traits<G>::edge_descriptor`.
`v`	An object of type `boost::graph_traits<G>::vertex_descriptor`.

Associated Types

boost::graph_traits<G>::out_edge_iterator

An out-edge iterator for a vertex v provides access to the out-edges of the vertex. As such, the value type of an out-edge iterator is the edge descriptor type of its graph. An out-edge iterator must meet the requirements of MultiPassInputIterator.

boost::graph_traits<G>::degree_size_type

The unsigned intergral type used for representing the number out-edges or incident edges of a vertex.

Valid Expressions

`source(e, g)`	Returns the vertex descriptor for u of the edge (u,v) represented by `e`. Return type: `vertex_descriptor`
`target(e, g)`	Returns the vertex descriptor for v of the edge (u,v) represented by `e`. Return type: `vertex_descriptor`
`out_edges(v, g)`	Returns an iterator-range providing access to the out-edges (for directed graphs) or incident edges (for undirected graphs) of vertex `v` in graph `g`. Return type: `std::pair<out_edge_iterator, out_edge_iterator>`
`out_degree(v, g)`	Returns the number of out-edges (for directed graphs) or the number of incident edges (for undirected graphs) of vertex `v` in graph `g`. Return type: `degree_size_type`

Complexity guarantees

The source(), target(), and out_edges() functions must all be constant time. The out_degree() function must be linear in the number of out-edges.

Concept Checking Class

  template <class G>
  struct IncidenceGraphConcept
  {
    typedef typename boost::graph_traits<G>::out_edge_iterator out_edge_iterator;
    void constraints() {
      function_requires< GraphConcept<G> >();
      function_requires< MultiPassInputIteratorConcept<out_edge_iterator> >();

      p = out_edges(v, g);
      e = *p.first;
      u = source(e, g);
      v = target(e, g);
    }
    void const_constraints(const G& g) {
      p = out_edges(v, g);
      e = *p.first;
      u = source(e, g);
      v = target(e, g);
    }
    std::pair<out_edge_iterator, out_edge_iterator> p;
    typename boost::graph_traits<G>::vertex_descriptor u, v;
    typename boost::graph_traits<G>::edge_descriptor e;
    G g;
  };

Jeremy Siek, Univ.of Notre Dame (jsiek@lsc.nd.edu)
Lie-Quan Lee, Univ.of Notre Dame (llee1@lsc.nd.edu)
Andrew Lumsdaine, Univ.of Notre Dame (lums@lsc.nd.edu)