igraph-help
[Top][All Lists]

## Re: [igraph] Centralization

 From: Simone Gabbriellini Subject: Re: [igraph] Centralization Date: Thu, 30 Oct 2008 18:56:41 +0100

```yes, that's what I needed!!!

thank you very very much,
simone

2008/10/30 Gábor Csárdi <address@hidden>:
> 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
>> 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
>>>> 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
>>>>>
>>>>> Tell us if you need more info...
>>>>>
>>>>> Gabor
>>>>>
>>>>> On Thu, Oct 30, 2008 at 5:51 PM, Simone Gabbriellini
>>>>>> 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
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> igraph-help mailing list
>>>>>> http://lists.nongnu.org/mailman/listinfo/igraph-help
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Gabor Csardi <address@hidden>     UNIL DGM
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> igraph-help mailing list
>>>>> http://lists.nongnu.org/mailman/listinfo/igraph-help
>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> igraph-help mailing list
>>>> http://lists.nongnu.org/mailman/listinfo/igraph-help
>>>>
>>>
>>>
>>>
>>> --
>>> Gabor Csardi <address@hidden>     UNIL DGM
>>>
>>>
>>> _______________________________________________
>>> igraph-help mailing list
>>> http://lists.nongnu.org/mailman/listinfo/igraph-help
>>>
>>
>>
>> _______________________________________________
>> igraph-help mailing list
>> http://lists.nongnu.org/mailman/listinfo/igraph-help
>>
>
>
>
> --
> Gabor Csardi <address@hidden>     UNIL DGM
>
>
> _______________________________________________
> igraph-help mailing list