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Hi

I made a few experiments myself. I created in Pajek 5 Random Erdos-Renyi
Undirected General Graphs with n=100, and avg. degree=3, and calclulated
their avg. geodesic distance with Pajek>Net>Paths between 2
vertices->Distribution of Distances->from all vertices. Results range from
3.69 to 4.62, i.e. they hover around the predicted 4.191 with quite some
variability.

Then I did the same for the network parameters I am interested in, i.e.
n=418 avg. degree=87. For all 5 networks I get an avg. geodesic of
1.79etc, which is consistently different from the predicted 1.35.
Could it be that the ln(n)/ln(avg.degree) formula applies only to sparse
networks?


Thanks,

Gianluca


> Did you make a Random Erdos-Renyi Undirected General Graph?
>
> The approximation you gave may be applied to only random ER graph. (there
> are more general approxiations that can be applied more general graph).
>
> And you get the average distance of graph using Net->Paths between 2
> vertices->Distribution of Distances->from all vertices menu.
>
> I did two experiments.
>
> 1. 100 nodes, average degree 3.
>     approximation : ln(100)/ln(3)=4.191, real : 4.41981
> 2. 1000 nodes, average degree 5.
>     approximation : ln(1000)/ln(5)=4.292, real : 4.48113
>
> Is it almost same?
>
> Best.
>
> ----- Original Message -----
> From: "[log in to unmask]" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, December 07, 2004 9:07 PM
>
>
> > *****  To join INSNA, visit http://www.insna.org  *****
> >
> > Hi everybody,
> >
> > The avg. geodesic distance in a (connected) random network is approximated
> by ln(n)/ln(k), where n=number_of_nodes , and k=avg._ties_per_node. However,
> if I create a random network with parameters n and k in Pajek and calcluate
> its avg. geodesic distance, I get sizeably different results (regardless of
> how large I set n). Any idea what I could be doing wrong?
> >
> >
> > Thanks,
> >
> > Gianluca
> >
> >
> > PS: To calculate the avg. geodesic distance I've been using
> > Ucinet/network/cohesion/distance -->adjacency
> >
> >
> >
> >
> >
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>

Gianluca Carnabuci
PhD candidate
University of Twente

P.O. Box 217
Enschede
The Netherlands

Ph: 0031 53 4892352



____________________________________________________________
Libero ADSL: 3 mesi gratis e navighi a 1.2 Mega, senza costi di attivazione.
Abbonati subito su http://www.libero.it

_____________________________________________________________________
SOCNET is a service of INSNA, the professional association for social
network researchers (http://www.insna.org). To unsubscribe, send
an email message to [log in to unmask] containing the line
UNSUBSCRIBE SOCNET in the body of the message.