Hi, I'm trying to have multiple visitors in the BFS algorithm, thus mixing two examples provided by the doc: http://www.boost.org/doc/libs/1_46_1/libs/graph/example/bfs-example.cpp and http://www.boost.org/doc/libs/1_46_1/libs/graph/doc/bfs_visitor.html What I have: ---------------------------------------------------------------------- #include <boost/graph/adjacency_list.hpp> #include <boost/graph/breadth_first_search.hpp> #include <iostream> enum { r, s, t, u, v, w, x, y, N }; const char *name = "rstuvwxy"; using namespace boost; class discover_visitor : public default_bfs_visitor { public: template < typename Vertex, typename Graph > void discover_vertex(Vertex u, const Graph & g) const { std::cout << "discover: " << name[u] << std::endl; } }; int main() { typedef adjacency_list < vecS, vecS, undirectedS > graph_t; graph_t g; boost::add_vertex(g); boost::add_vertex(g); boost::add_vertex(g); boost::add_vertex(g); boost::add_vertex(g); boost::add_edge(r, s, g); boost::add_edge(s, u, g); boost::add_edge(t, v, g); std::vector<double> dist(N); discover_visitor vis; breadth_first_search(g, vertex(s, g), boost::visitor( make_bfs_visitor( std::make_pair(record_distances(&dist[0], on_tree_edge()), vis) ) ) ); return EXIT_SUCCESS; } ---------------------------------------------------------------------- This produces a lot of g++ errors such as:
/usr/include/boost/graph/breadth_first_search.hpp:311:5: instantiated from ‘void boost::breadth_first_search(const VertexListGraph&, typename boost::graph_traits<Graph>::vertex_descriptor, const boost::bgl_named_params<P, T, R>&) [with VertexListGraph = boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS>, P = boost::bfs_visitor<std::pair<boost::distance_recorder<double*, boost::on_tree_edge>, discover_visitor> >, T = boost::graph_visitor_t, R = boost::no_property, typename boost::graph_traits<Graph>::vertex_descriptor = long unsigned int]’ bfs.cc:49:24: instantiated from here /usr/include/boost/graph/visitors.hpp:138:44: error: no type named ‘event_filter’ in ‘class discover_visitor’ /usr/include/boost/graph/visitors.hpp:139:51: error: no type named ‘event_filter’ in ‘class discover_visitor’
The problem seems to come from the 2nd pair argument 'vis'. It compiles if I repeat the first argument of the pair two times, ie: std::make_pair(record_distances(&dist[0], on_tree_edge()), record_distances(&dist[0], on_tree_edge())) I tried to define an 'event_filter' in my visitor class: typedef on_discover_vertex event_filter; But then I get other g++ errors:
/usr/include/boost/graph/visitors.hpp:109:8: error: no match for call to ‘(discover_visitor) (long unsigned int&, const boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS>&)’
Is it possible to have self-defined visitors in an EventVisitorList? And if so, how? I'm using boost 1.46.1 with g++ 4.6. Thanks! -- Maxime