[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [igraph] ARPACK error in igraph 0.6

From: Tamas Nepusz
Subject: Re: [igraph] ARPACK error in igraph 0.6
Date: Wed, 16 Nov 2011 15:22:45 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1


ARPACK seems to throw up on some degenerate graphs; this is known but we
haven't figured out yet what can be done about it. One of our users has even
had a graph where the full graph threw an ARPACK error, but removing any
arbitrary edge from the graph resolved the problem:


I don't know what could be causing this, but if you are willing to share the
graph with me (just upload it somewhere where I can download it and send the
URL to my private email address), I'll take a look.

Also, may I ask you which igraph function are you trying to run on the graph
when you get this error?


On 11/16/2011 01:22 AM, Leo Alekseyev wrote:
> I am trying to compute the page rank of a graph with ~50,000 vertices
> and 300,000 edges.  I'm using the R interface to the latest nightly of
> igraph (igraph_nightly_0.6-2591-20111110).  I keep running into the
> following error:
> At arpack.c:961 : ARPACK error, The Schur form computed by LAPACK
> routine dlahqr could not be reordered by LAPACK routine dtrsen.
> After some googling, I tried increasing the ARPACK iteration limit by
> settting igraph.arpack.default$maxiter <- 50000, but it didn't help.
> Any suggestions about dealing with the error are appreciated :)
> --Leo
> _______________________________________________
> igraph-help mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/igraph-help

reply via email to

[Prev in Thread] Current Thread [Next in Thread]