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