Re: [Bug-gsl] bugs when using gsl_sf_hyperg_U

[Feng Gao]

Hi,

Sorry for so many emails... I also tried the GSL SHELL software and it
seemse that sf.hypergU(1, -500, 0.1) can be calculated correctly. However,
I found that any negative non-integers of b for U(a, b, x) cannot be
calculated. These negative non-integers should be suitable arguments and
the manual states that b is of type double.

Thanks very much for your attention and I will be very grateful if you can
resolve these problems.

Best Regards,

Feng


2014-03-10 21:01 GMT-04:00 Feng Gao <address@hidden>:

> Sorry for the typo but for example 1) listed in the previous email:
>
> gsl_sf_hyperg_U(1, -500, 0.1) gives the correct value: ~1.99e-3.
>
> The problem happens when calculating gsl_sf_hyperg_U(1, -500, 40): gsl:
> gsl: hyperg.c:165: ERROR: overflow. The value should be ~0.00184 so I
> suppose this is a bug.
>
> Again, thanks very much if you can help me solve this problem since I very
> much need it in my research.
>
> Best Regards,
>
> Feng
>
>
> 2014-03-10 19:53 GMT-04:00 Feng Gao <address@hidden>:
>
> Hi,
>>
>> I have been using the gsl_sf_hyperg_U function for a while and I found
>> several bugs when calculating normal values. For example,
>>
>> 1) gsl_sf_hyperg_U(1, -500, 0.1) gives incorrect value: 9.3246e+03, which
>> actually should be around 0.19.
>>
>> 2) Many domain error bugs. For example, gsl_sf_hyperg_U(1, -6.67, 1)
>> should have value ~0.128 but will invoke domain error for gsl.
>>
>> Hope that you can further investigate this and come up with solutions.
>> Thanks!
>>
>> Best Regards,
>>
>> Feng
>>
>
>