Re: [Boost-users] Bessel and Hypergeometric functions wanted, was: (no subject)

Subject: Re: [Boost-users] Bessel and Hypergeometric functions wanted, was: (no subject)
From: David Bergman (davidrbergman_at_[hidden])
Date: 2012-03-19 08:14:58

This may be a snippet from a question I submitted.  Thanks for replying.
There are many values of arguments for the Hypergeometric function for which it does not reduce to another special function.
So in a nutshell that was the use case, a generic hypergeometric function that could not be expressed as another special function.

Also, in my post I mentioned that the boost documentation listed these as unsupported TR1 functions.  Can you clarify what this means?  Does TR1 handle hypergeometric functions? 

Thanks,
David



________________________________
 From: John Maddock <boost.regex_at_[hidden]>
To: boost-users_at_[hidden] 
Sent: Monday, March 19, 2012 4:38 AM
Subject: Re: [Boost-users] Bessel and Hypergeometric functions wanted, was: (no subject)
 
>> 2.  Does Boost plan to have hypergeometric functions in the future?
>> 
> I've only found hypergeometric distributions:
> http://www.boost.org/doc/libs/1_48_0/libs/math/doc/sf_and_dist/html/math_toolkit/dist/dist_ref/dists/hypergeometric_dist.html

Right, I've deliberately avoided hypergeometetic functions, because, although they're theoretically attractive - you can represent anything as a hypergeometric after all - they're pretty much untestable (domain of functions with >3 args is too great for any kind of coverage), and except for the trivial use cases, the "obvious" implementations either don't converge or aren't numerically stable.  In other words it's better to stick with more "special" special functions with a more limited domain that can actually be tested/implemented in a reasonably comprehensive manner.

What was the use case for the hypergeometrics BTW - was it to implement a special function that we don't otherwise have?

HTH, John. 
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