Cedric,
Thanks! This however, is completely useless to me. I can't afford to
duplicate the entire graph in memory! Is there some other way to
achieve this? Maybe I could write to boost-developers for a feature
request or something?
-rhl
On Wed, Dec 29, 2010 at 6:36 AM, Cedric Laczny
Hi,
On Wednesday, 29. December 2010 04:19:04 Ryan Lewis wrote:
Hi,
Lets say your handed an arbitrary boost graph and an iterator to a subset of it's vertices. You want to induce a subgraph of this graph. How do you do this?
I looked at the boost docs and found the Subgraph < Graph > page:
http://www.boost.org/doc/libs/1_36_0/libs/graph/doc/subgraph.html
Indeed there exists a subgraph member function:
subgraph<Graph>& create_subgraph();
However this suggests, as does the example, that you want to take an induced subgraph of a graph whose type is Subgraph < Graph >. However my graph is just of type Graph. What is the right way to deal with this? I've tried asking at #boost, but no one seems to be awake there.
Maybe you could use boost::copy_graph()? At least it works for me when copying a filtered_graph into and adjacency_list. It's a comparable example where you "convert" one graph-type (loosely speaking) into another. Also have a look at the boost example code of subgraph. Basically, I would copy the _whole_ graph into a "subgraph<...> BigG", create a "subgraph<...> subG" from the subgraph BigG (the naming scheme may be a bit awkward at first sight) and then iterate over the vertex-set (probably need to newly create it to match the new vertices) and insert those vertices (and the respective edges) into the subG. AFAIK, copy_graph() only works for complete graphs and not for vertex-subsets, e.g. specified by an iterator_range. AFAIK, a subgraph is either the complete graph or a subgraph relative to a bigger subgraph ( also note local and global vertices), therefor the call for create_subgraph(). Another idea that jumps to my head is to use filtered_graph ( and a filter matching your vertices of interest) on the BigG and copy the resulting filtered_graph into subG, created via create_subgraph().
Hope that helps
Thanks,
-rhl _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
Best,
Cedric _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users