[SciPy-dev] scipy.special.hyp2f1 bug?
Wed Sep 16 20:22:20 CDT 2009
On Wed, Sep 16, 2009 at 9:15 PM, <email@example.com> wrote:
> On Wed, Sep 16, 2009 at 9:02 PM, Skipper Seabold <firstname.lastname@example.org> wrote:
>> Since y'all are looking at the distributions vs. mpmath, it reminded
>> me of this. I haven't filed a bug report yet, but I don't think one
>> existed when I found this.
>> I was working with the connection between the incomplete beta function
>> and the hypergeometric2f1 function in scipy.special for GLM in
>> statsmodels and I came across this blog post on mpmath about some
>> corner cases for the hypergeometric2f1.
>> Two examples of discrepancies.
>> In : import mpmath
>> In : from scipy import special
>> In : mpmath.hyp2f1(3,-1,-1,0.5)
>> Out: mpf('2.5')
>> In : special.hyp2f1(3,-1,-1,.5)
>> Out: 8.0
>> In : mpmath.hyp2f1(1,1,4,3+4j)
>> Out: mpc(real='0.49234384000963544', imag='0.60513406166123973')
>> In : special.hyp2f1(1,1,4,3+4j)
>> Out: (0.65925460474847919+1.3277887264473263j)
>> I will file a bug report shortly, if we think mpmath is correct vs. scipy.
> there is a ticket for special.hyp2f1 for values that are used in rdist:
> but the parameter values in your case look different.
Ah, ok. I don't think I saw that one. I will just piggyback there then.
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