[Top][All Lists]

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

Re: [igraph] Eigenpairs of sparse graphs

From: David Morton
Subject: Re: [igraph] Eigenpairs of sparse graphs
Date: Sun, 9 Mar 2008 22:38:30 +0100

Thanks for your prompt answer.
I forgot to mention that I use igraph in R. Is there a way to do the same
job from R by avoiding calls to C functions.

On Sun, Mar 9, 2008 at 9:38 PM, Tamas Nepusz <address@hidden> wrote:

> I need to compute some extremal eigenvalues/eigenvectors of
> adjacency and Laplacian matrices for very large and sparse graphs.
> (to large for the matrices to be represented in their dense form
> anyway).
> Given the graphs, how can I achieve this task with igraph?
igraph includes an interface to the ARPACK library suitable for
solving large scale eigenvalue problems. See the following page in the
documentation for details:


So you should import your graph somehow into igraph (using the C core
directly), initialize an igraph_arpack_options_t data structure, set
its options appropriately for your specific problem, implement an
igraph_arpack_function_t function that multiplies a given vector with
your matrix (chances are that you'll have to use an adjacency list
representation of your graph, see http://cneurocvs.rmki.kfki.hu/igraph/doc/html/igraph-Adjlists.html)
, and finally call igraph_arpack_rssolve if your matrix is symmetric,
igraph_arpack_rnsolve otherwise.

If you need examples, check the code for PageRank calculation or
eigenvector centrality in centrality.c in the igraph source code.

I hope this helps.


igraph-help mailing list

David Morton de Lachapelle
reply via email to

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