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Re: [igraph] Alpha Centrality Function Crashes
From: |
Gabor Csardi |
Subject: |
Re: [igraph] Alpha Centrality Function Crashes |
Date: |
Thu, 24 Apr 2008 18:04:29 +0200 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Judd,
I get
> g <- erdos.renyi.game(40000, 90000, type="gnm")
> alpha.centrality(g)
Error in get.adjacency(graph) :
At vector.pmt:408 : cannot reserve space for vector, Out of memory
Yes, this function uses an adjacency matrix, so you cannot use it
on such a big graph. You can try the 'Matrix' package.
See the code of 'alpha.centrality', get the edge list of
the graph with 'get.edgelist', convert it to a (sparse) Matrix,
and solve the equation with the sparse matrix solver.
It should not be too difficult, i can help you if you need help.
Gabor
On Thu, Apr 24, 2008 at 08:37:10AM -0700, Judd Antin wrote:
> Hi all,
>
> I've been using igraph in R to look at a a very large, sparse directed
> network of about 58,000 nodes and 87,000 edges. I am interested in
> calculating alpha centrality scores, but the alpha.centrality function
> crashes R for me instantaneously. I've tried this on both Windows and
> Mac builds of the library (in case of a platform dependent issue), with
> the same results.
>
> Does anyone have any insight on how I could get this to work? Is the
> size of the network simply too large? I also noticed in the manual that
> 'singular adjacency matrices' can cause problems for the algorithm, but
> I'm not sure what a 'singular adjacency matrix' is.
>
> Any advice appreciated.
>
> Thanks!
>
> --Judd
>
> --
> Judd Antin
> School of Information
> University of California Berkeley
> address@hidden
> web: http://technotaste.com
> blog: http://technotaste.com/blog
>
>
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> igraph-help mailing list
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--
Csardi Gabor <address@hidden> UNIL DGM