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From: | Colin Garroway |
Subject: | Re: [igraph] Betweennes centrality (maximum and normalization) |
Date: | Wed, 10 Feb 2010 11:19:31 -0500 |
centrality.norm<-function(graph,type=c("degree","closeness","betweenness"),centralization=FALSE)
{
result<-NA
g<-graph
cent<-centralization
if (!is.igraph(g)) {stop("Not a graph object")}
if (type[[1]] == "degree") {
if (!cent) result <- degree(g)/(vcount(g)-1)
else result <- (sum(max(degree(g))-degree(g)))/((vcount(g)-1)*(vcount(g)-2))}
else if (type[[1]] == "betweenness") {
temp <- 2*betweenness(g)/((vcount(g)-1)*(vcount(g)-2))
if (!cent) result <- temp
else result <- sum(max(temp)-temp)/(vcount(g)-1)}
else if (type[[1]] == "closeness") {
if (!cent) result <- closeness(g)
else result <- (2*vcount(g)-3)*(sum(max(closeness(g))-closeness(g)))/((vcount(g)-1)*(vcount(g)-2))}
else {stop("this type is unavailable or mispelled")}
return(result)
}
Stefan, I am not sure that I understand your questions correctly, but
I think Freeman's paper might answer them:
Centrality in social networks conceptual clarification
Linton C. Freeman
Social Networks, 1979
Gabor
ps. google for it to get a PDF if you don't have sciencedirect access
--
On Wed, Feb 10, 2010 at 5:05 PM, Stefan Kroeger <address@hidden> wrote:
> Hi,
>
> I hope it's okay to ask a pretty special question to betweenes
> centrality (BC) and not directly related to igraph.
>
> (mention: I deal with the node-related BC in undirected graphs.)
>
> my two problems/questions are:
> (i) Is the highest measure BC of network, also the theoretical hightest
> reachable (maximum) BC for the graph?
>
> (ii) Is there a way to normalize the betweennes centrality measures to
> be able to compare between different graph?
>
>
> thanks a lot
> Stefan
>
>
> _______________________________________________
> igraph-help mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/igraph-help
>
Gabor Csardi <address@hidden> UNIL DGM
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