Re: [igraph] Centralization

[Gábor Csárdi]

Ooops, you are completely right, for degree the correct formula is

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

So basically you have to divide by the (un-normed) centralization of
the "most central" network. For degree this network is the star.

Gabor

On Thu, Oct 30, 2008 at 6:44 PM, Simone Gabbriellini
<address@hidden> wrote:
> maybe it's just something basic that I don't understand, but I am used
> to think centralization in a range from 0 to 1... now I have things
> like 22.791...
>
> where's the trick? ;)
>
> Simone
>
> 2008/10/30 Gábor Csárdi <address@hidden>:
>> Yes, it is. Gabor
>>
>> On Thu, Oct 30, 2008 at 6:30 PM, Simone Gabbriellini
>> <address@hidden> wrote:
>>> Thanks Gabor,
>>>
>>> I got it, yes it is simple for my case (degree centralization), just one 
>>> line:
>>>
>>> centralization<-sum(max(degree(g))-degree(g)) / (vcount(g)-1)
>>>
>>> is it correct?
>>>
>>> Best regards,
>>> Simone
>>>
>>> 2008/10/30 Gábor Csárdi <address@hidden>:
>>>> Simone, it is not included in igraph, but it is not hard to do it,
>>>> only,  you need to calculate the theoretical maximum of the vertex
>>>> level centrality score "by hand". But this is easy for degree, it is
>>>> basically vcount()-1 if you don't allow loop edges.
>>>>
>>>> See  http://lists.gnu.org/archive/html/igraph-help/2008-06/msg00043.html
>>>> for more info.
>>>>
>>>> Tell us if you need more info...
>>>>
>>>> Gabor
>>>>
>>>> On Thu, Oct 30, 2008 at 5:51 PM, Simone Gabbriellini
>>>> <address@hidden> wrote:
>>>>> Hi List,
>>>>>
>>>>> is there a function in igraph to calculate graph centralization -
>>>>> based on degree or betweenness or closeness?
>>>>>
>>>>> I am sure you already know those references, but I put them here anyway:
>>>>>
>>>>> Freeman, L.C. (1979). ``Centrality in Social Networks I: Conceptual
>>>>> Clarification.'' Social Networks, 1, 215-239.
>>>>> Wasserman, S., and Faust, K. (1994). Social Network Analysis: Methods
>>>>> and Applications. Cambridge: Cambridge University Press
>>>>>
>>>>>
>>>>> best regards,
>>>>> Simone
>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Gabor Csardi <address@hidden>     UNIL DGM
>>>>
>>>>
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>>>
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>>
>>
>>
>> --
>> Gabor Csardi <address@hidden>     UNIL DGM
>>
>>
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-- 
Gabor Csardi <address@hidden>     UNIL DGM