[boost] incident (graph stuff)

From: jsiek_at_[hidden]
Date: 1999-12-12 00:43:01

So I was experimenting with an implementation of the
bellman-ford algorithm, and it's just a little bit
more elegant if I use this function you suggested.

Dietmar Kuehl writes:
 > incident
 >   nodes of an edge, ie.
 > 
 >     incident(e,g)  pair<V,V>  get descriptors for the nodes incident
 >                               to an edge.

Cool thing is, we don't really have to add it to the graph
requirements, we can just define it once as follows:

template <class Edge, class Graph>
std::pair<typename graph_traits<Graph>::vertex_descriptor,
          typename graph_traits<Graph>::vertex_descriptor>
incident(Edge e, Graph& g)
{
  return make_pair(source(e,g), target(e,g));
}

If a graph supports both source() and target(), then this is
valid, otherwise not, which is fine.

Cheers,

Jeremy

----------------------------------------------------------------------
 Jeremy Siek
 Ph.D. Candidate                  email: jsiek_at_[hidden]
 Univ. of Notre Dame         work phone: [phone]
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 SGI                                www: http://www.lsc.nd.edu/~jsiek/
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