Re: [Boost-users] Creating a mst graph from another, undirected one

18 Feb 2005

      Hi,

first of all, thank you for your quick answer. However, i have yet some
questions :)

Thu, Feb 17, 2005 egunean, Doug Gregor-k zera esan zuen :
...
On Feb 17, 2005, at 6:31 AM, aitor wrote:
...
typedef adjacency_list <
 boost::listS,
 boost::vecS,
 boost::undirectedS,
 VertexProperties,
 EdgeProperties> UGraph;
typedef adjacency_list <
 boost::listS,
 boost::vecS,
 boost::directedS,
 VertexProperties,
 EdgeProperties> MSTree;
void createGraph() {
UGraph g;
add_vertices();
 add_edges();
 compute_edges_weights();
vector 
 mst_edges(num_vertices(g));
 kruskal_minimum_spanning_tree(g, back_inserter(mst_edges));
// At this point i want to create another graph of type MSTree from
 // g and mst_edges. How can i do it efficiently ?
}
// Build the vertices with:
MSTree mst(num_vertices(g);
// Since both graphs use VertexListS=vecS, we can mega-cheat and build 
the graph like this:
for (int i = 0; i < mst_edges.size(); ++i)
  add_edge(source(mst_edges[i], g), target(mst_edges[i], g), mst);
Ok. But the problem is that, as that the original graph isn't directed,
neither are the edges. So, i can't determine wether
source(mst_edges[i],g) is the "father" or the "son" of the edge in the
mst tree.

regards
					aitor