Re: [igraph] igraph_community_leading_eigenvector_step implementation

[Al]

Gabor
igraph_community_leading_eigenvector has its own step function. Please
refer line 1276 of the communities.c R package source file.
Thanks, Al


On Sat, Jan 10, 2009 at 1:04 PM, Gábor Csárdi <address@hidden> wrote:
> Al, as far as I can see both these functions do the same. The
> modularity is not explicitly calculated, but according to the original
> paper, and also http://arxiv.org/abs/physics/0602124 the leading
> eigenvector of the modularity matrix will be negative if the split
> would decrease the modularity, and in this case we don't split.
>
> I don't really know what difference you can see between the two
> functions, but I coded these quite a while ago, so can't remember all
> the details, so I might be wrong.
> Where does igraph_community_leading_eigenvector calculate the modularity?
>
> Best,
> Gabor
>
> On Sat, Jan 10, 2009 at 6:06 PM, Al <address@hidden> wrote:
>> Hi
>>
>> I am a developer tasked with generalizing the implementation of the M.
>> Newman community detection algorithm to accept weighted edges. We want
>> to use the step wise variation of the function (located in
>> communities.c under the igraph_community_leading_eigenvector_step
>> function). On inspection of the source code, it is not obvious to me
>> that he modularity calculation is actually being preformed. However,
>> in the non-step was variation of the function
>> (igraph_community_leading_eigenvector), I notice that it is properly
>> implemented. So I am wondering if the step wise variation is properly
>> implemented? and if so maybe some insight could be shed on where it is
>> preforming the M. Newman modularity calculation.
>>
>> Thanks
>> Al Tucker
>>
>>
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>>
>
>
>
> --
> Gabor Csardi <address@hidden>     UNIL DGM
>
>
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