Re: [Repast-developer] Barabasi-Albert net

[Laszlo G. <lg...@ai...>]

Hi,

Back in 2001 I was in e-mail correspondence with Prof. Barabasi, and
asked the same question. His answer was that they were always using
a fully connected initial network, even though 'it should work' with
other configurations, too.

I hope this helps,

-- g
--=20
Gulyas Laszlo   |     Laszlo Gulyas
kut.ig.         |  dir. of research
AITIA Rt.       |         AITIA Inc.

<quote who=3D"Bj=F6rn Lijnema">
> Hello everyone,
>
> I managed to find some time to write the Barabasi-Albert network
> generator I mentioned on this list a few weeks back. (Actually I
> called it a scale free network generator, but  Laszlo Gulyas pointed
> out my error). I'm afraid it was a bit of a rush job, but I think it
> should work correctly.
>
> There is one  issue though, in Emergence of Scaling in Random Networks
> Barabasi and Albert say that the network can have a small number of
> initial vertices, however they do not mention anything about
> connecting those initial vertices to each other.
>
> This would mean, with their formula (the probability formula of the
> probability for a new vertex being connected to an existing vertex i
> being the number of i's edges divided by the total number of edges)
> that you will get unconnected vertices if the number of initial
> vertices is not equal to the number of edges each vertex has.
>
> Of the initial vertices, those that do not have a connection after the
> first new vertex has been connected, will never get one since the
> probability that a new vertex will connect to them is always zero.
>
> I chose to just connect all initial nodes to each other, mainly
> because I really didn't know what to do.  I noticed that JUNG
> (jung.sf.net) chose another way to go, by changing p =3D degree(v) / |E=
|
> to p =3D (degree(v) + 1) / (|E| + |V|)
>
>
> If someone could look over my code and point out/correct any errors
> I've made, and make suggestions for the initial nodes problem, I would
> be most thankful.
>
>
> Bj=F6rn Lijnema
>