Re: [igraph] Community Detection using leading eigenvector

[Gábor Csárdi]

You can follow this issue here:
https://bugs.launchpad.net/igraph/+bug/914258

FYI. Best,
Gabor

On Mon, Dec 19, 2011 at 2:23 PM, Andrei Boutyline
<address@hidden> wrote:
> Thanks for considering the suggestion.  I am curious, would implementing
> just support for valued edges (without support for asymmetric edges) be
> easier?  I would still be very glad to see just this this half of the change
> implemented, if it's much easier than implementing the whole change.
>
> Thanks again,
> Andrei
>
>
> On Mon, Dec 19, 2011 at 7:34 AM, Gábor Csárdi <address@hidden> wrote:
>>
>> Thanks for the suggestion. Yes, this is in theory a relatively easy
>> change.
>>
>> In practice it is not, however. The reason for that is that the
>> non-symmetric ARPACK eigensolver that is used to find the leading
>> eigenvector is not very well behaved. Many times it gives you the
>> wrong eigenvector, or no useful result at all.
>>
>> Best,
>> Gabor
>>
>> On Mon, Dec 19, 2011 at 6:19 AM, Claudio Martella
>> <address@hidden> wrote:
>> > I too second your feature request, it would be highly appreciated.
>> >
>> > On Mon, Dec 19, 2011 at 3:40 AM, Andrei Boutyline
>> > <address@hidden> wrote:
>> >> I would like to enthusiastically second this feature request.  It would
>> >> be
>> >> really wonderful if the eigenvector community detection method was
>> >> generalized to weighted graphs.  As far as I can tell, the change just
>> >> consists of using the sum of incoming edge weights instead of vertix
>> >> degree,
>> >> and of normalizing the modularity by the total sum of all edge weights
>> >> instead of by the total number of ties.  I would be very grateful if
>> >> someone
>> >> on the igraph team could make this change!
>> >>
>> >> Thanks a lot!
>> >> Andrei
>> >>
>> >> On Sat, Dec 17, 2011 at 3:21 AM, Denzil Correa <address@hidden>
>> >> wrote:
>> >>>
>> >>> Hi,
>> >>>
>> >>> I would like Prof. Newman's "Leading Eigenvector for Community
>> >>> Detection"
>> >>> algorithm on a weighted directed graph. I currently see an
>> >>> implementation
>> >>> for just the undirected (and unweighted) version. Am I missing
>> >>> something OR
>> >>> has this been left out?
>> >>>
>> >>> Thanks.
>> >>>
>> >>> --
>> >>> Regards,
>> >>> Denzil
>> >>>
>> >>>
>> >>> _______________________________________________
>> >>> igraph-help mailing list
>> >>> address@hidden
>> >>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>> >>>
>> >>
>> >>
>> >>
>> >> --
>> >> Andrei Boutyline
>> >> University of California, Berkeley
>> >> PhD Student, Sociology
>> >> www.ocf.berkeley.edu/~andrei
>> >>
>> >> _______________________________________________
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>> >> address@hidden
>> >> https://lists.nongnu.org/mailman/listinfo/igraph-help
>> >>
>> >
>> >
>> >
>> > --
>> >    Claudio Martella
>> >   address@hidden
>> >
>> > _______________________________________________
>> > igraph-help mailing list
>> > address@hidden
>> > https://lists.nongnu.org/mailman/listinfo/igraph-help
>>
>>
>>
>> --
>> Gabor Csardi <address@hidden>     MTA KFKI RMKI
>>
>> _______________________________________________
>> igraph-help mailing list
>> address@hidden
>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>
>
>
>
> --
> Andrei Boutyline
> University of California, Berkeley
> PhD Student, Sociology
> www.ocf.berkeley.edu/~andrei
>
> _______________________________________________
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> address@hidden
> https://lists.nongnu.org/mailman/listinfo/igraph-help
>



-- 
Gabor Csardi <address@hidden>     MTA KFKI RMKI