Re: [Boost-users] [graph] : newbie question on brandes_betweenness_centrality

Subject: Re: [Boost-users] [graph] : newbie question on brandes_betweenness_centrality
From: Matthew Walker (matthew.walker.1_at_[hidden])
Date: 2009-09-21 12:12:31

Thank you very much for your help Andrew!  With your comments and a bit
of trial-and-error, I found the following works:

  int lNumberOfVertices = num_vertices(g);

  typedef boost::exterior_vertex_property<Graph, float>
BetweennessProperty;
  typedef BetweennessProperty::container_type Container;
  typedef BetweennessProperty::map_type Map;

  Container lCont(lNumberOfVertices, 0 );
  Map lMap(lCont, g);

  brandes_betweenness_centrality(g, lMap);
  double lCentralization = central_point_dominance(g, lMap);
  double lScaler = 2.0/(lNumberOfVertices*lNumberOfVertices -
3*lNumberOfVertices +2);
  lCentralization *= lScaler;


Cheers again,

Matthew

Andrew Sutton wrote:
> >  
> > ... // I am reading a network from a file and storing it into lEdges
> > and lNumVertices
> >  typedef adjacency_list<vecS, vecS, undirectedS  > Graph;
> >  Graph g(lEdges.begin(), lEdges.end(), lNumVertices);
> >     
> >  typedef boost::exterior_vertex_property<Graph, float>
> > BetweennessProperty;
> >  typedef BetweennessProperty::map_type BetweennessMap;
> >     
> >  BetweennessMap lMap;
> >  brandes_betweenness_centrality(g, lMap);
> > }
> >     
> > If I could get this to work, I then have aspirations that the helper
> > function central_point_dominance(g, lMap) might give me the betweenness
> > centralization measure that I'm after.
> >     
> > Thanks in advance for your help!
> >   
>
> I would consider steering clear of the exterior_vertex_property
> template for now. I haven't had a chance to fully document it and it
> may change in future releases. It is very much an undocumented feature.
>   
> The lack of documentation is causing your problem. An exterior property
> requires two components: a container, which associates data with
> vertices and edges, and the property map, which abstracts the
> association into something usable in a generic manner. Your property
> map is not actually bound to a container (perpahps the default
> constructor should be private). I think, what you really want to write
> is:
>   
> typedef BetProperty::container_type Container;
> t4ypedef BetProperty::map_type Map;
>   
> Container cont(g, /* default value */ );
> Map map(cont);
>   
> The container is constructed over the graph, assigning a default value
> to each vertex. The map is bound to the container.
>  
> Andrew Sutton
>   [e-mail]