> page.rank has been running forever: [...] > on > > IGRAPH DN-- 12062801 15279166 -- > attr: name (v/c) > > is this normal? Not sure but I wouldn't rule it out -- your graph is pretty large and ARPACK can be a tad bit slow. I have just tried it on an Erdos-Renyi graph of similar size and it also did not terminate for a while. On the other hand, you might be experiencing a convergence issue with ARPACK. Sometimes it happens that ARPACK fails to detect convergence (at least within the machine epsilon) and performs the maximum number of allowed iterations with essentially no improvement after the first few iterations -- then it bails out with a warning saying that the maximum number of iterations has been reached. Try increasing the epsilon value a bit when invoking page.rank() to see if it terminates faster or not. Or decrease the maximum number of iterations allowed. I'm not familiar with the R interface but I think there is an options=... argument to page.rank where you can specify some options that ARPACK will use.
An alternative solution if you are feeling adventurous and you don't mind compiling igraph from source: try the 0.7-prpack branch of igraph (downloadable from Github): https://github.com/igraph/igraph/tree/0.7-prpack This branch uses the excellent PRPACK package instead of ARPACK to calculate PageRank scores. PRPACK does all sorts of neat tricks to ensure faster convergence for PageRank calculations. The branch will be merged with the 0.7 development tree sooner or later but it still needs more testing. All the best, Tamas _______________________________________________ igraph-help mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/igraph-help
