Hi, I have finally managed to implement my genome assembly algorithm! Except one part is too slow. I'm doing a breadth first search starting from each vertex i in an undirected graph, looking for its mate-pair (another given vertex j, of approximately known distance, where distance is the same as summed edge weight). Ideally I want to follow the BFS until either (i) I find the mate-pair vertex j (ii) I have visited all vertices up to some given distance away from the source vertex i. I want to bail out of the algorithm at the first occurrance of either (i) or (ii) and not carry on to search through the rest of the graph, which is very large. So I'm wondering if anybody has had a similar requirement and if they implemented a BFS visitor which accomplishes it? I have managed to limit it to the same connected component, but it still takes too long. The limiting distance is small and so I could just write something, but it would obviously be more elegant to use a BFS visitor. Thanks for any advice, Adam. -- Dr Adam Spargo High Performance Assembly Group email: aws@sanger.ac.uk Wellcome Trust Sanger Institute Tel: +44 (0)1223 834244 x7728 Hinxton, Cambridge CB10 1SA Fax: +44 (0)1223 494919 -- The Wellcome Trust Sanger Institute is operated by Genome Research Limited, a charity registered in England with number 1021457 and a company registered in England with number 2742969, whose registered office is 215 Euston Road, London, NW1 2BE.