Re: [igraph] Re: alpha in power.law.fit

[Simone Gabbriellini]

this is in the help of the function ppareto(q, location, shape)

x, q     vector of quantiles.
location, shape  the alpha and k parameters.

I will try degreenet, the function bsdp() should do this, but I find
it a little bit complicated... where is alpha and k there?

cheers,
Simone


2009/3/5 Gábor Csárdi <address@hidden>:
> I think so, but are you sure that 'location' is actually 'alpha'? If
> you use ppareto from the VGAM package, then the 'location' parameter
> should be calculated from the normalization criteria, IMHO.
>
> Btw., why don't you directly fit a Pareto distribution to the data? I
> am sure that there is an R package that can do this, probably take a
> look at 'degreenet' first.
>
> G.
>
> On Thu, Mar 5, 2009 at 5:42 PM, Simone Gabbriellini
> <address@hidden> wrote:
>> Thanks Gabor,
>>
>> btw, is it correct to assume that the k parameter is equal to alpha-1?
>>
>> simone
>>
>> 2009/3/5 Gábor Csárdi <address@hidden>:
>>> Yep, coef(fit) is slightly better, as it likely works with the results
>>> of many kind of fitting functions.
>>>
>>> Best,
>>> G.
>>>
>>> On Thu, Mar 5, 2009 at 5:20 PM, Simone Gabbriellini
>>> <address@hidden> wrote:
>>>> SOLVED...
>>>>
>>>> it was easy...
>>>>
>>>>> fit<-power.law.fit(x)
>>>>> address@hidden
>>>>   alpha
>>>> 1.754803
>>>>
>>>> best regards,
>>>> simone
>>>>
>>>> 2009/3/5 Simone Gabbriellini <address@hidden>:
>>>>> hi list,
>>>>>
>>>>> I'd like to use the alpha coefficient I've found with power.law.fit(),
>>>>> but I am not able to extract it from the mle object... what is the
>>>>> right sintax?
>>>>>
>>>>> I need it in order to plot the distribution with:
>>>>>
>>>>> plot(ppareto(table(my.data.frame$score), location=alpha, shape=
>>>>> alpha-1), type="p")
>>>>>
>>>>> thanks,
>>>>> simone
>>>>>
>>>>
>>>>
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>>>>
>>>
>>>
>>>
>>> --
>>> Gabor Csardi <address@hidden>     UNIL DGM
>>>
>>>
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>>
>>
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>
>
>
> --
> Gabor Csardi <address@hidden>     UNIL DGM
>
>
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