***** To join INSNA, visit http://www.insna.org ***** <<<-------- Joshua O'Madadhain-------->>> > ***** To join INSNA, visit http://www.insna.org ***** > > Emmanouil: > > What is it that this is in aid of? > > First: I assume that by "geodesic" you mean "shortest path", in which > case the lengths of all shortest paths will (by definition) be the > same, and so this matrix would not be able to distinguish between > "lots of short paths" and "few long paths". Perhaps this is your > intent, of course. > > Second: Depending on the topology of your network, there can be an > exponential number of such paths connecting two vertices. > > So it may be worth reconsidering whether calculating this matrix is a > good solution to whatever problem you're trying to solve. If you want a short algorithm see page 63 in Batagelj, V: Semirings for social networks analysis. J Math Sociol 19 (1994)1: 53-68 You get two matrices. The answer to your question is a matrix with elements d[i,j]*c[i,j] . For larger (some thousands of nodes) networks faster algorithm can be developed following Brandes' approach. Vlado -- Vladimir Batagelj, University of Ljubljana, FMF, Department of Mathematics Jadranska 19, 1000 Ljubljana, Slovenia http://vlado.fmf.uni-lj.si _____________________________________________________________________ SOCNET is a service of INSNA, the professional association for social network researchers (http://www.insna.org). To unsubscribe, send an email message to [log in to unmask] containing the line UNSUBSCRIBE SOCNET in the body of the message.