On Wed, 25 Jan 2012, Andriy Gapon wrote:
on 24/01/2012 23:03 Jeremiah Willcock said the following:
In order to do that, the easiest way is to create a new undirected graph from your original graph, adding each directed edge as an undirected edge in the new graph. If you have very large graphs, there are (more complicated) ways to do that without extra memory utilization, but this approach involves the least effort and works unless your graphs are very large or you are doing this operation many times.
My graph is actually a quite large (directed) adjacency_matrix. Actually, I need to run connected_components() on a filtered_graph of the said graph (based on edge weight). So I think that I found a way to achieve what I wanted, but I would like to double-check my approach with you.
I arranged my filter to be such that each edge of the filtered graph has an opposite edge - for each (u, v) there is a (v, u). And then I use exactly the same approach as boost::connected_components(), but without any limitations on a directionality of a graph.
If you have both directions of each edge, the normal connected_components code (possibly with the directionality check commented out) should work just fine.
That is, I also use depth_first_search(). I think that since depth_first_search() colors only the vertices, then it should work on my graph in the same way as it would work on an undirected graph.
Yes, I think so.
And thus it should find the weekly connected components that I want. What do you think?
That's the way I would recommend doing it.
P.S. It seems that the connected_components documentation mentions only the first version of the connected_components function.
Having two versions is an implementation detail; the second one implements the "= all defaults" part of the signature given in the documentation. -- Jeremiah Willcock