vertex labels in igraph from adjacency matrix

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Btw, you will likely want to take the betweenness call out, and call  
it once and store the result, instead of calling it twice (well,  
assuming the graph is largish). Or even better, use which.max:

which.max(betweenness(graph = my.graph, v=V(my.graph), directed =  
FALSE))

This is almost good, but there is a catch, in igraph vertices are 
numbered from zero. So if you want an igraph vertex id, then you 
need to subtract one from this, i.e.:

maxb <- which.max(betweennness(my.graph, directed=FALSE))-1

You can double check it:

betweenness(my.graph, maxb, directed=FALSE)

Gabor

PS. there is also an igraph mailing list, see the igraph homepage
at igraph.sf.net

Haris Skiadas
Department of Mathematics and Computer Science
Hanover College

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Csardi Gabor <csardi at rmki.kfki.hu>    UNIL DGM