Re: [Boost-users] (no subject)

Hi, On Wednesday, 6. April 2011 12:55:52 Gabriel Marchand wrote:

Hi, I am new to boost and I face the same problem mentioned here with "connected_components()" using a mutable graph (hence using a list for the vertex container). I try the detailed solution of Aaron Windsor in the previous post but I still get some errors at compilation. Here is my little code:

#include #include

using namespace std; using namespace boost;

Box& b = conf.GetBox();

You seem to use your own classes and you do not provide the definition. Thus this is unfortunately not a minimal example. So in the future, it might facilitate help from others to you, with this in the back of your head.

if (!ai) { ai = new AtomList(); *ai = conf.GetAtoms().AtomSelector(selecti, b); }

typedef boost::adjacency_list< listS, listS, undirectedS, property, no_property>

> graph_t;

graph_t g(ai->size()); property_map::type index = get(vertex_index, g);

With listS as the vertex container, I would expect it to fail here. An adjacency_list with listS does not automatically create a vertex_index property. So you might give vecS a try. Especially, if you insert most of the vertices (if not all) at one specific moment and you are not constantly changing the number of vertices in the graph, I think it will make no big difference in performance whether you use vecS or listS. But you have the benefit of automatic vertex_index property-creation. I can however not compile your example (s. above) nor did you provide the error message you get, so I can't tell you for sure if this is the source of error.

graph_traits::vertex_iterator vi, vi_end; graph_traits::vertices_size_type cnt = 0; for(tie(vi,vi_end) = vertices(g); vi != vi_end; ++vi) put(index, *vi, cnt++);

for (unsigned int i = 0; i < ai->size(); ++i) { Cartesian& crdi = ai->GetElement(i)->pos; for (unsigned int j = i + 1; j < ai->size(); ++j) { Cartesian& crdj = ai->GetElement(j)->pos; double r = conf.GetBox().CartesianDistance(crdi, crdj); if (r < rcut) { add_edge(vertex(i,g), vertex(j,g), g); // Add edge to Map if distance criteria is satisfied

} } }

vector<int> component(num_vertices(g)); int num_clusters = connected_components(g, &component[0], vertex_index_map(index));

The compilation is successfull until I add the last line: int num_clusters = connected_components(g, &component[0], vertex_index_map(index));

This confuses me a bit, as I would expect the error in an earlier line. So you might look forward to provide your error message or a really working, minimal example.

Hope somebody can give a hint

Hope this helps.

gabriel

Best, Cedric