Re: [igraph] errors using power.law.fit

[Martin Tomko]

Hi guys,
yes, that is my reading of the paper too. NOw, what is the relation of 
the BFGS method suggested by Gabor and the method they use? Can I apply it?

I do indeed have discrete data (as anyone working with graph degree 
distributions would) and I understand that there is no single perfect 
power law adistribution I could fit to it, but I need an approximation. 
The alpha parameter and possibly an estimate of the goodness of fit 
(btw, I am accessing the result of the power law fiting as follows:
fitdegS4<-power.law.fit(degrees,method="BFGS")
alpha<- coef(fitdegS4)[[1]])

is there any simpler method to get the alpha and if possible the 
parameters? I am still not sure how best to access S4 objects, seems 
like you need a method, and I only found coef for a mle -class object, 
but nothing for the goodness of fit parameter which actually gets 
displayed if I only list fitdegS4....


Thanks
Martin

On 11/16/2010 11:28 AM, Tamas Nepusz wrote:
> > Which is quite surprising, because there is no exact formula for
> > discrete data AFAIK.
> >      
> Correction: no, they don't calculate alpha directly, they just simply
> try every possible alpha with some granularity in a given range,
> calculate the likelihood, and then choose the alpha which yields the
> maximal likelihood.
>
>