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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 |
Hello,
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:
https://bugs.launchpad.net/igraph/+bug/365817
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?
Cheers,
Tamas
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
>
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