Ethan Kim writes:
Hi all,The long standing question I've had for BGL is how to easily convert a
graph (using adjacency_list) from listS as vertex list to vecS. (And vice versa)
I understand why there needs to be 2 different implementations depending on
different uses of algorithms. But is there an easy way to convert them back and
forth?Any tip would be much appreciated.Thanks,
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Do you mean given Graph A using listS you want to produce Graph B using vecS?
How about something like this:
template
void foo(const GraphFrom& from,GraphTo& to) {
typedef typename GraphFrom::vertex_iterator viter;
typedef typename GraphFrom::vertex_descriptor vdesc;
typedef typename GraphFrom::edge_iterator eiter;
typedef std::map map_t;
map_t table;
viter vi,vend; //copy vertices
for(tie(vi,vend)=from.vertices(); vi!=vend; ++vi)
table[*vi] = add_vertex(to);
eiter ei,eend; //copy edges
for(tie(ei,eend)=from.edges(); ei!=eend; ++ei) {
vdesc s = source(*ei,from);
vdesc t = target(*ei,from);
add_edge(table[s],table[t]);
}
}
Assuming my template mangling is correct, this should produce an isomorphic
graph of the corresponding type in about O( VlgV + ElgE ) time.
Justin
