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

Subject: Re: [Boost-users] Bessel and Hypergeometric functions wanted, was: (no subject)
From: John Maddock (boost.regex_at_[hidden])
Date: 2012-03-19 09:15:27

>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?

Yes, they were added to the TR1 spec.  However, that's part of the TR that 
did not make it into C++11 and to my knowledge no one has actually 
implemented them for the reasons I gave.  I believe GSL has them 
(http://www.gnu.org/software/gsl/manual/html_node/Hypergeometric-Functions.html), 
but once you dig into the code there are lots of comments to the effect that 
they don't always behave well in some regions - and that's just the bits 
they've managed to test - to repeat, a function with > 3 real valued args is 
untestable over the whole domain, that's *why* they're broken down into more 
precisely defined functions.

Regards, John.