Re: [Boost-users] [BGL,Graph] bundle and property maps

From: Johan Oudinet (johan.oudinet_at_[hidden])
Date: 2005-11-17 18:19:50

On 11/17/05, Stephane Grabli <Stephane.Grabli_at_[hidden]> wrote:
> Hi,
>
> I'm (still) trying to use the strong components algorithm with
> a graph storing vertices as a list (listS).
> I've learned thanks to this mailing list that I had to explicitely
> declare and intialize a vertex_index map.
> The declaration of my graph type should
> therefore look like that:
>
> typedef adjacency_list<listS, listS,
> directedS,property<vertex_index_t,std::size_t> > Graph;
>
> and the component map should be declared this way:
> typedef graph_traits<Graph>::vertices_size_type v_size_t; //the range of
> ComponentMap
> vector_property_map< v_size_t, property_map<Graph,
> vertex_index_t>::type> componentMap(num_vertices(g), get(vertex_index,g)
> );  //g is an instance of Graph
>
> I would like to know if there is a way to combine this with
> the use of bundles. In practice, I used to have this declaration
> for my graph type:
>
> typedef adjacency_list<listS, listS, directedS,VertexBundle> Graph;
>
> with:
> struct VertexBundle{
>    int id;
> };
>
> How should I merge these two types of declarations?
> Is there a way to define the required vertex_index as a bundle
> property and to use it to define my component map afterward?
> Thanks!
>
Yes, there is a way... see my answer to your previous thread on the
same subject...
With your example:
strong_components ("your previous arguments",
          vertex_index_map (get (&VertexBundle::id, g)))
So the algorithm strong_components uses your property id as a
map<vertex, index> for its vertex_index_map and not its default
argument (get(vertex_index, g)), which doesn't exist for your
container (listS).

--
Johan