topological_sort

(1)
template <class VertexListGraph, class OutputIterator>
void topological_sort(VertexListGraph& G, OutputIterator iter)

(2)
template <class VertexListGraph, class OutputIterator, class Visitor>
void topological_sort(VertexListGraph& G, OutputIterator iter,
                      Visitor visit)

(3)
template <class VertexListGraph, class OutputIterator, 
          class ColorMap, class DFSVisitor>
void topological_sort(VertexListGraph& G, OutputIterator iter, 
                      ColorMap color, DFSVisitor visit)

The topological sort algorithm creates a linear ordering of the vertices such that if edge (u,v) appears in the graph, then u comes before v in the ordering. The graph must be a directed acyclic graph (DAG). The implementation consists mainly of a call to depth_first_search().

Requirements on Types

• The graph type must be a model of VertexListGraph.
• Vertex descriptors of the graph will be output to the OutputIterator, which must model OutputIterator.
• The type Visitor must be a model of Visitor.
• The ColorMap must be a ReadWritePropertyMap and vertex descriptors from the graph must be usable as the map's key type.
• The DFSVisitor type must be a model of DFSVisitor.

Example

Calculate a topological ordering of the vertices.

  typedef adjacency_list< vecS, vecS, directedS, color_property<> > Graph;
  typedef boost::graph_traits<Graph>::vertex_descriptor Vertex;
  Pair edges[7] = { Pair(0,1), Pair(2,4),
                    Pair(2,5),
                    Pair(0,3), Pair(1,4),
                    Pair(4,3), Pair(5,5) };
  Graph G(6, edges, edges + 7);

  typedef std::vector< Vertex > container;
  container c;
  topological_sort(G, std::back_inserter(c));

  cout << "A topological ordering: ";
  for ( container::reverse_iterator ii=c.rbegin(); ii!=c.rend(); ++ii)
    cout << index(*ii) << " ";
  cout << endl;

  A topological ordering: 2 5 0 1 4 3