[R] Weighted networks and multigraphs

[Gabor Csardi]

Dear Andrew,

we've created a package called igraph, but the current version does not
really support weighted graphs, so it's not much good for you. 
It can do weighted minimum spanning tree, but this is probably all.
Also it can't handle multigraphs.

I'm writing this email because if you end up writing these routines for
yourself, you might consider to extend igraph. igraph contains many routines
for non-weighted graphs and might be easier for you to use these as a
baseline. Most routined are written in C because we need speed for very
large graphss but you can also add your extensions in R if you like.
Just an option. Also, we will add routines for weigthed graphs, but
currently this is not the current direction of the development, so it might
take a few months. (Although the direction changes quite often.....)
Multigraph support is not planned and very unlikely to be added.

See http://cran.at.r-project.org/src/contrib/Descriptions/igraph.html and 
http://cneurocvs.rmki.kfki.hu/igraph

FYI,
Gabor

On Wed, Mar 01, 2006 at 08:53:06AM -0000, Wilson, Andrew wrote:
> I would like to apply network measures (such as betweenness centrality,
> upper boundedness, etc.) to a weighted graph with non-integer weights,
> defined by a euclidean distance matrix.  The package sna provides the
> measures that I want to use, but seems only to operate on binary graphs.
> I have read work by Mark Newman
> (http://aps.arxiv.org/abs/cond-mat/0407503/), who suggests that a
> weighted graph can be transformed into an unweighted multigraph, to
> which such measures can be applied.  It seems that the package giRaph
> contains a function to handle multigraphs, but there is no example in
> the manual to show how it is used.  I am also not sure whether this
> multigraph structure can be used as input into the relevant functions in
> the sna package.  Can anyone advise?
> 
> Many thanks,
> Andrew Wilson
> 
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-- 
Csardi Gabor <csardi at rmki.kfki.hu>    MTA RMKI, ELTE TTK