Hi All, In the latest version of scipy I updated the algorithm used to find strongly connected components of a directed graph. The code lives in scipy.sparse.csgraph.connected_components. I've written up a blog post which explains how this algorithm works and also the memory optimisations which were made to greatly improve the capacity of the scipy implementation. http://www.timl.id.au/?p=327 If noone objects I'll update the documentation in the code to point to this page, as I think it provides a useful explanation of the algorithm which is not available elsewhere. Cheers, Tim