Re: [Bug-gsl] Negative a or b in gsl_sf_hyperg_2F1_e()

[Evgeny Stambulchik]

Brian Gough wrote:
> Evgeny Stambulchik writes:
>  > Since the 2F1 series is finite for either a or b being negative, this
>  > should be used irrespectively of whether the absolute values are below
>  > 10.0 (why this specific value, BTW?).
>
> Have you done any comparisons or testing to confirm whether this is
> better?

Well, I mean - for (|a| > 10 || |b| > 10) the function (the original 
variant of it) refuses to work at all. So I'd say it's better with the 
patch ;-). Now, I didn't compare results for integer negative a or b 
below 10 (by abs. value), but don't think a sum of a few (< 10) terms 
can introduce any noticeable rounding errors.

Best regards,

Evgeny