Re: [Boost-users] Compile error when using breadth_first_search with these adjacency_list template parameters

On May 8, 2009, at 11:45 AM, Julian wrote:

Hi,

I get one compiler error when using breadth_first search with the adjacency list shown below.

template < typename Vertex> class bfs_reachable_set_visitor : public default_bfs_visitor { public: bfs_reachable_set_visitor(set<Vertex>* bucket): m_set(bucket) { } template < typename Graph > void discover_vertex(Vertex u, const Graph & g) { m_set->insert(u); } set<Vertex>* m_set; };

typedef adjacency_list RectAreaGraph; typedef graph_traits<RectAreaGraph>::vertex_descriptor VDescriptor; struct RectGraphVertexData {};

void some_func() { RectAreaGraph g; set<VDescriptor> reachableSet;

bfs_reachable_set_visitor<VDescriptor> setvis(&reachableSet);

breadth_first_search(g, *(vertices(g).first), visitor(setvis));

}

The error:

<snip>

For now, since it compiles with vecS, I can change to that, but I would prefer to have setS for edge and listS for vertex.

You need to provide either a "color map" or, if you use the default color_map, a vertex_index_map that maps vertex_descriptors into the range [0, num_vertices(g)). When you use vecS for the vertex list it has a vertex_index_map by default, but not so when you use listS for the vertex_list: http://www.boost.org/doc/libs/1_39_0/libs/graph/doc/ breadth_first_search.html Here is an example that uses listS for the vertex_list and makes color a vertex property: http://www.boost.org/doc/libs/1_39_0/libs/graph/example/bfs-example2.cpp -- Michael