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

[Martin Tomko]

hi Tamas,
thanks for your response. How would one call the C code from R? I may be 
able to install the C library. I would then have to somehow link it to 
my R installation and send it the graph object or the matrix with 
degrees that I get as result of degree(g), and get back an indication 
that I can or cannot fit it with the power.law.fit function, right?

Or would the C method do the Kolmorgov-Smirnov test AND the fitting. 
thus if I wanted to do it all in R, I just use a standard Kolmorgov-Smirnov?

Also, the article seems to imply - in the recipe part - that you 
estimate the alpha and Xmin parameters, and then test with the Kolmorgov 
Smirnov test for goodness of fit. Now, this implies that I still may run 
into troubles with the optim() error I got our of R. would you have any 
suggestion how to get rid of that?

Thanks
Martin



On 11/16/2010 10:07 AM, Tamas Nepusz wrote:
> Dear Martin,
>
>    
> > Now, it is possible that some of the graphs I have would not fit a power law 
> > well - is there a recommended way for checking whether it makes sense at all to 
> > try fitting one?
> >      
> You can use a Kolmogorov-Smirnov test for that, as outlined here:
>
> http://arxiv.org/abs/0706.1062
>
> There is also a plain C implementation of their method which will eventually be 
> integrated with igraph (once I find time for it). Currently it is a separate 
> project, but it works from the command line, so you can simply call out from R 
> to this implementation if you want to do batch processing:
>
> https://github.com/ntamas/plfit
>
> (Instructions: download, cmake, make, make install).
>
>