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: 2014-01-20 07:19:12

Hi Alex and all,

  Examine Vertex

vis.examine_vertex(u, g)

void

This is invoked on a vertex as it is popped from the queue. This happens
immediately before examine_edge() is invoked on each of the out-edges of
vertex u.

"Examine" seems to work once on first encounter (is that correct??) so
might worth a try.
I did try the code below but I got errors on the part the works with the
color map. Any ideas?

class dijkstra_2step : public boost::default_dijkstra_visitor
{
public:
    dijkstra_2step(std::vector<Weight> dists, double threshold):
distances(dists), threshold(threshold) {}

    void examine_vertex(boost::graph_traits <unGraph>::vertex_descriptor u,
const unGraph& g){
        boost::property_map< unGraph, boost::vertex_color_t >::type
colorMap = boost::get(boost::vertex_color, g);
        if( distances[u] > threshold ) colorMap[u] =
boost::color_traits::black();
    }
    std::vector<Weight> distances;
    double threshold;
};

Thanks