Re: [igraph] how to generate directed small world networks

[Gábor Csárdi]

Simone,

with barabasi.game you only model the in-degree distribution. What you
can do is "plugging in" the out-degree distribution. But I think this
is all, really. The reciprocity will be still zero.

If you want to model both the in- and out-degree distribution, then
you need another model. E.g. you can take a look at
'forest.fire.game'. Perhaps there are others in the literature.

Best,
Gabor

On Sun, Mar 15, 2009 at 11:23 AM, simone gabbriellini
<address@hidden> wrote:
> Gabor,
> yes, I mean that. Thank you for the suggestion. May I ask a question about
> barabasi.game too?
> I see that in each step it add a vertex and some edges to old vertices
> already in the network with a certain probability. And that it is possible
> to make attractive also the isolated vertex with the zero.appeal parameter.
> g.emp is my empiric network. The indegree distribution produced with:
> g.sf<-barabasi.game(n=g.emp.vcount, power=0.08, m=14, zero.appeal = 1.6)
> is close to my data, as you can see
> here: http://www.digitaldust.it/papers/analysis.pdf
> (red = empiric, blue = scale free)
> but the outdegree distribution is far from the empiric one...
> I see also that the reciprocity(g.sf) is equal to 0, which is another bad
> result for me...
> do you have any suggestion in order to modify it to "improve" the fit of the
> outdegree distribution?
> or to increase the reciprocity?
> I apologize if my questions are obvious or implicit in the nature of the
> scale-free model.
> Best,
> Simone
> Il giorno 15/mar/09, alle ore 11:09, Gábor Csárdi ha scritto:
>
> Simone, you mean Watts-Strogatz type? Create a lattice first, and then
> call rewire. edges on it. E.g.
>
> g2 <- rewire.edges(graph.lattice(100, nei=2, dir=TRUE, mutual=TRUE),
> p=2/100)
> plot(g2, layout=layout.circle, vertex.label=NA, vertex.size=3,
> edge.arrow.size=0.4)
>
> Best,
> Gabor
>
> On Sat, Mar 14, 2009 at 3:17 PM, Simone Gabbriellini
> <address@hidden> wrote:
>
> Dear List,
>
> is it possible to generate directed small world in the igraph R package?
>
> thanks,
>
> simone
>
>
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> Gabor Csardi <address@hidden>     UNIL DGM
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-- 
Gabor Csardi <address@hidden>     UNIL DGM