Re: [Boost-users] [Graph] initialize_vertex change vertex color (visitor)

Subject: Re: [Boost-users] [Graph] initialize_vertex change vertex color (visitor)
From: The Maschine (justthemaschine_at_[hidden])
Date: 2014-01-14 09:09:27

I probably need to give a bit clearer description for what I need to do.

I would like to build a visitor that accesses the colour_map of a specific
vertex. The idea is to 'hide' some vertices from the search completely.

I have found that the possible solution might be through the
'initialize_vertex()' or do you think some other trick is better?

Best

On Mon, Jan 13, 2014 at 11:38 AM, The Maschine <
justthemaschine_at_[hidden]> wrote:

> Hi all,
>
> I would like to build a visitor (for dikstra) with the initialise_vertex
> acting as 'colour map' modifier.
> I want to exclude some vertices from the search based on a condition.
> So I want to set some vertices 'black' in the init part of the algorithm.
>
> class dijkstra_2step : public boost::default_dijkstra_visitor
>
> {
>
> public:
>
>     dijkstra_2step(std::vector<Weight> dists, double threshold): distances(dists), threshold(threshold) {}
>
>
> // THIS PART IS NOT CORRECT!!!! //
>
>     void initialize_vertex(boost::graph_traits <unGraph>::vertex_descriptor u, const unGraph& g){
>
>         if( distances[u] > threshold ) color[u] = black; // ??????
>
>     }
>
> //////////
>
>
>     std::vector<Weight> distances;
>
>     double threshold;
>
> };
>
>
>
> Any help for the above visitor? How to I access the colour?
>
> I couldn't find something online.
>
>
> Thanks
>
>