Boost C++ Libraries

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Graph

The Graph concept contains a few requirements that are common to all the graph concepts. These include some associated types for vertex_descriptor, edge_descriptor, etc. One should note that a model of Graph is not required to be a model of Assignable, so algorithms should pass graph objects by reference.

Notation

G

A type that is a model of Graph.

g

An object of type G.

Associated Types

boost::graph_traits<G>::vertex_descriptor

A vertex descriptor corresponds to a unique vertex in an abstract graph instance. A vertex descriptor must be Default Constructible, Assignable, and Equality Comparable.

boost::graph_traits<G>::edge_descriptor

An edge descriptor corresponds to a unique edge (u,v) in a graph. An edge descriptor must be Default Constructible, Assignable, and Equality Comparable.

boost::graph_traits<G>::directed_category

This type shall be convertible to directed_tag or undirected_tag.

boost::graph_traits<G>::edge_parallel_category

This describes whether the graph class allows the insertion of parallel edges (edges with the same source and target). The two tags are allow_parallel_edge_tag and disallow_parallel_edge_tag.

boost::graph_traits<G>::traversal_category

This describes the ways in which the vertices and edges of the graph can be visited. The choices are incidence_graph_tag, adjacency_graph_tag, bidirectional_graph_tag, vertex_list_graph_tag, edge_list_graph_tag, and adjacency_matrix_tag.

Valid Expressions

boost::graph_traits<G>::null_vertex()

Returns a special boost::graph_traits<G>::vertex_descriptor object which does not refer to any vertex of graph object which type is G.

Concept Checking Class

template <class G> struct GraphConcept { typedef typename boost::graph_traits<G>::vertex_descriptor vertex_descriptor; typedef typename boost::graph_traits<G>::edge_descriptor edge_descriptor; typedef typename boost::graph_traits<G>::directed_category directed_category; typedef typename boost::graph_traits<G>::edge_parallel_category edge_parallel_category; typedef typename boost::graph_traits<G>::traversal_category traversal_category; void constraints() { BOOST_CONCEPT_ASSERT(( DefaultConstructibleConcept<vertex_descriptor> )); BOOST_CONCEPT_ASSERT(( EqualityComparableConcept<vertex_descriptor> )); BOOST_CONCEPT_ASSERT(( AssignableConcept<vertex_descriptor> )); BOOST_CONCEPT_ASSERT(( DefaultConstructibleConcept<edge_descriptor> )); BOOST_CONCEPT_ASSERT(( EqualityComparableConcept<edge_descriptor> )); BOOST_CONCEPT_ASSERT(( AssignableConcept<edge_descriptor> )); } G g; };