[Graph] betweenness_centrality - output completed percentage?

Hello all, I calculate the betweenness-centrality of a large graph (V:150k, E:500k, boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS,) with boost::brandes_betweenness_centrality and I can find how to get a indication of the 'completed' part of the algorithm. For example this graph took 1h:38m (single thread 10.8 iMac 3.4ghz) to complete but in order to be able to know the execution time of larger graph im a bit lost... On "one to all" BFS you know how many vertices you have left but this algorithm seems to me lacking a custom visitor or something in order to output some data. Any ideas as Im really new to boost.graph? Thanks a lot, Tasos

Hi Tasos, The outer loop of betweenness centrality is a loop over all the vertices in the graph with each used as the source of a shortest paths computation. If you want to see how far along the algorithm is you can just instrument the "for (boost::tie(s, s_end) = vertices(g); s != s_end; ++s)" in brandes_betweenness_centrality_impl(). Note that you don't actually need to count shortest paths from *every* vertex in the graph to get a good approximation of betweenness centrality, check out this paper [1]. Sampling the vertices in the graph and counting shortest paths from a subset of them should significantly speed up betweenness centrality if a (relatively good) approximation will work for your application. Cheers, Nick [1] http://www.cc.gatech.edu/~bader/papers/ApproxBC.html On Jan 22, 2013, at 8:04 AM, Tasos wrote:
Hello all,
I calculate the betweenness-centrality of a large graph (V:150k, E:500k, boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS,) with boost::brandes_betweenness_centrality and I can find how to get a indication of the 'completed' part of the algorithm.
For example this graph took 1h:38m (single thread 10.8 iMac 3.4ghz) to complete but in order to be able to know the execution time of larger graph im a bit lost...
On "one to all" BFS you know how many vertices you have left but this algorithm seems to me lacking a custom visitor or something in order to output some data.
Any ideas as Im really new to boost.graph?
Thanks a lot, Tasos
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Nick Edmonds
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Tasos