Re: Hypergeometric functions [message #27645 is a reply to message #27519] |
Mon, 29 October 2001 22:34   |
Ralf Flicker
Messages: 19 Registered: October 2001
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Junior Member |
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Craig Markwardt wrote:
>
> Ralf Flicker <rflicker@gemini.edu> writes:
>
>> Does anybody know of an available IDL implementation for
>> generalized hypergeometric functions ? I need in particular
>> 2F3(a,b;c,d,e;z^2), which is absolutely convergent for all real
>> z. I can't seem to find anything among the standard sources, but
>> thought I'd check here before I start coding it myself.
>
> Hi Ralf--
>
> I see you haven't gotten a response to this question for the past
> several days. I think the answer is that IDL is pretty weak on
> special functions, although it does have a few.
>
> However, the particular hypergeometric function you are seeking is
> rather esoteric. I cannot find it in the GNU scientific library, nor
> in CEPHES. These are two C libraries of special functions. [ Nor,
> for that matter, can I find it cursorily in Abramowitz & Stegun. ] It
> looks like you will have to code this yourself.
>
> If it's really convergent then it should be rather simple to code the
> series directly.
Yes, that's what I ended up doing, and it works fine. I realize
the function is somewhat special (the only substantial reference
to 2F3 that I could find on the web was to a Mathematica
implementation), but I was partly fishing for information in
general about these kinds of special functions. As you say, IDL
is a mite weak on this point.
ralf
--
Ralf Flicker UIN : 65334076
Gemini Observatory http://www.gemini.edu/
670 N. A'Ohoku Pl. Tel : (808) 974-2569
Hilo 96720, HI, USA Fax : (808) 935-9235
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