page.rank caused unknown ARPACK error
Bug #976229 reported by
Casper Petersen
This bug affects 2 people
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
igraph |
New
|
Undecided
|
Unassigned |
Bug Description
Given a large (1.4 million edges), connected, directed, unweighted graph in the edgelist format "imported" using read.graph with the latest igraph (igraph 0.5.4) causes the following error:
g <- read.graph(
k <- page.rank(g, v=V(g), directed=TRUE);
Error in page.rank(g, v=V(g), directed = TRUE):
At arpack.c:586 : ARPACK error, Unknown ARPACK error
I found a previous bug-report concerning this, where the user was advice to use igraph 0.6 - maybe I have missed something but that does not seem to exist.
To post a comment you must log in.
There is a bug in igraph 0.5.4 due to which an incorrect error message is shown in this case; the real error message would be as follows:
"The Schur form computed by LAPACK routine dlahqr could not be reordered by LAPACK routine dtrsen."
Anyway, the solution to this issue would be to raise the "ncv" parameter of the underlying ARPACK routine, but this is unfortunately not yet possible in igraph 0.5.4. We are currently fixing issues with eigenvector calculations for the upcoming igraph 0.6 release. igraph 0.6 is not released yet, but you can give it a try by installing it from source; the nightly snapshots are to be found here:
http:// code.google. com/p/igraph/ downloads/ list
Alternatively, please send me the graph you are working with, I'll calculate the PageRank values for it and send them back to you. This would also help us confirm that igraph 0.6 will not have problems with graphs like yours.