[SciPy-User] scipy.stats.distributions.erlang - "boring" consensus building in a ticket

nicky van foreest vanforeest@gmail....
Mon May 7 06:13:09 CDT 2012


> Do you think it would be useful to have fit() restrict to integers?
>
> I guess currently nobody uses erlang.fit() because, at least in the
> example, it doesn't work with default parameters.
>
> import numpy as np
> from scipy import stats
>
> #add fitstart to erlang, otherwise it doesn't work
> stats.erlang._fitstart = stats.gamma._fitstart
>
> np.random.seed(876589)
> rvs = stats.erlang.rvs(5, size=500)
>
> for dist in [stats.erlang, stats.gamma]:
>    print '\n', dist.name
>    p0 = dist.fit(rvs)
>    print stats.gamma.nnlf(p0, rvs), p0
>    print
>
>    for k in range(10):
>        p = dist.fit(rvs, f0=k)
>        print dist.nnlf(p, rvs), p

I think it returning an int is here to be exptected by an Erlang user.
Hence, yes.

I ran the above code, but got some warnings:

Warning: invalid value encountered in subtract

I did not pursue the origin of this though.

>
> Josef
>
>>
>> Nicky
>>
>>
>>
>> On 5 May 2012 22:20,  <josef.pktd@gmail.com> wrote:
>>> Should we restrict the shape parameter to be an integer instead of a float?
>>>
>>> http://projects.scipy.org/scipy/ticket/1647
>>>
>>> Let's ask the users:
>>>
>>> Does anyone want an exception if the shape parameter is not an integer?
>>> Is there a demand or use case for estimating the shape parameter as an
>>> integer instead of a float?
>>>
>>> right now erlang and gamma are essentially the same, as far as I can see
>>>
>>> Josef
>>> _______________________________________________
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>>> SciPy-User@scipy.org
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