Re: [igraph] using igraph to calculate PageRank

[Gábor Csárdi]

AFAIK, page rank does not work for non-symmetric matrices (i.e.
directed graphs) in 0.5.x. See e.g.
https://bugs.launchpad.net/igraph/+bug/526106

Gabor

On Fri, Jun 3, 2011 at 9:00 AM, Tamas Nepusz <address@hidden> wrote:
> Hello Ana,
>
> Thanks for the bug report, I'm investigating it right now. You can follow
> the progress of the issue here:
>
> https://bugs.launchpad.net/igraph/+bug/792352
>
> --
> Tamas
>
> On 06/02/2011 06:52 PM, Ana Sofia Morais wrote:
>> Hello,
>>
>>
>>
>> I am having problems using igraph in order to calculate the weighted form of
>> PageRank for the nodes in a weighted graph. Here is the code I am using.
>>
>>
>>
>> library(igraph)
>>
>> m <-
>> matrix(c(0,0,0,0,0,4,0,0,0,0,0,0,0,0,5,0,0,0,5,0,0,0,0,0,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,0,4,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,4,0,0,0,0,0,0,0),
>> nrow=9, ncol=9)
>>
>> tm <- t(m)
>>
>> net = graph.adjacency(tm, mode="directed", weighted=TRUE)
>>
>> prt = page.rank (net, directed = TRUE, damping = 0.85, weights = NULL)$ 
>> vector
>>
>>
>>
>> R returns the following error message:
>>
>>
>>
>> Error in page.rank(net, directed = TRUE, damping = 0.85, weights = NULL) :
>>
>>   At arpack.c:586 : ARPACK error, Unknown ARPACK error
>>
>>
>>
>> However, this problem does not occur when matrix  /m/ is not transposed.
>>
>>
>>
>> I would be thankful for any suggestions on how to solve this problem.
>>
>>
>>
>> With best wishes,
>>
>>
>>
>> Sofia
>>
>>
>>
>>
>>
>> _______________________________________________
>> igraph-help mailing list
>> address@hidden
>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>
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>



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