Re: [igraph] Search for k-cliques

[Gabor Csardi]

On Fri, May 16, 2008 at 04:37:58PM +0200, Gabor Csardi wrote:
> Look at the function 'igraph_transitivity_local_undirected2' in 
> the file 'structural_properties.c'. There is a part like this:
> 
>         if (neis[nei2] == node+1) {
>           VECTOR(triangles) [ nei2index-1 ] += 1;
>           VECTOR(triangles) [ neiindex-1 ] += 1;
>           VECTOR(triangles) [ nodeindex-1 ] += 1;
>         }
> 
> That's where a triangle is found. I don't really have time now
> to check the code, i think the three vertices in the triangle are 
> nei2index-1, neiindex-1 and nodeindex-1. You need to store that somewhere 

Ooops, not quite, it should be nei, nei2 and node.

G.

> and then return the result, plus write an R interface to the function 
> if you want to get the result from R. I'm not saying that it is 
> trivial....
> 
> G.
> 
> On Fri, May 16, 2008 at 04:24:53PM +0200, Lacón Grelos wrote:
> > HI Gabor.
> > Thanks for your answer.
> > I will need the list, actually. Which is the kind of conding you are  
> > thinking about?
> > Best
> > 
> > El 16/05/2008, a las 16:17, Gabor Csardi escribió:
> > 
> > >Hi, you need the list of triangles? Or just the number of them?
> > >In the latter case do a motif detection. The former is more
> > >difficult, i'm afraid that you need to modify some C code for
> > >that.
> > >
> > >G.
> > >
> > >On Fri, May 16, 2008 at 03:44:38PM +0200, Lacón Grelos wrote:
> > >>  Hi i-graphers
> > >>  I am trying to recover all triangles (3-cliques) in my graph (200000
> > >>nodes and 1.2 Million links) with the igraph function "cliques".
> > >>Unfortunately computation time is huge (>1day !). I was wondering
> > >>wether this is normal and if there is any other faster way to get the
> > >>k-cliques in my graph (with k small).
> > >>  Thanks in advance.
> > >>  Best
> > >>
> > >>
> > >>
> > >>_______________________________________________
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> > >
> > >-- 
> > >Csardi Gabor <address@hidden>    UNIL DGM
> > >
> > >
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> > 
> > 
> > 
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> 
> -- 
> Csardi Gabor <address@hidden>    UNIL DGM
> 
> 
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-- 
Csardi Gabor <address@hidden>    UNIL DGM