[R] about centralization

[Simone Gabbriellini]

Weijia,

if you only need degree centralization, Gabor suggests me those lines  
of code and they work great:

## undirected graph
centralization<-(sum(max(degree(g))-degree(g)))/(vcount(g)-1)/ 
(vcount(g)-2

## directed graph
centralization<-(sum(max(degree(g))-degree(g)))/(2*vcount(g)-1)/ 
(vcount(g)-2

hope it helps,
Simone


Il giorno 30/nov/08, alle ore 17:05, Gábor Csárdi ha scritto:

> Weijia, centralization was not included in igraph, because really, it
> takes only writing a one line function to do it. But it is on our TODO
> list and will be included soon.
>
> E.g. for degree see the thread that starts here:
> http://lists.gnu.org/archive/html/igraph-help/2008-11/msg00064.html
>
> You can do it similarly for other measures, but first you need to find
> out which structure is the most centralized for a given measure. E.g.
> for degree it is the star graph, but not for eigenvector centrality.
> Probably this is written in the classic Wasserman-Faust book.
>
> Best,
> Gabor
>
> On Sun, Nov 30, 2008 at 1:37 PM, Weijia You <weijiawx at gmail.com>  
> wrote:
>> Hi all,
>>
>> Is there anyone who ever used igraph to calculate the index of
>> "centralization" ?
>> I tried my best but can't find it in igraph.
>>
>> The brief introduction to "centralization" can be found here , and  
>> I think
>> it's an important index for measuring the centrality on the  
>> aggregated
>> level.(http://faculty.ucr.edu/~hanneman/nettext/C10_Centrality.html)
>>
>> Thank you for any comments and suggestions.
>>
>> Best wishes!
>>
>> Weijia
>>
>>       [[alternative HTML version deleted]]
>>
>> ______________________________________________
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>>
>
>
>
> -- 
> Gabor Csardi <Gabor.Csardi at unil.ch>     UNIL DGM
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.