Re: [boost] C++ Standard Library proposal - Math functions forStatistics

From: Gabriel Dos Reis (gdr_at_[hidden])
Date: 2003-04-23 15:15:28

"Paul A. Bristow" <boost_at_[hidden]> writes:

| Indeed, I doubt if long double is practically useful for many applications -
| even 16 decimal place 64-bit double will be impracticable on MSVC where there
| isn't really a long double (you may need to use 80-bit calculations to get a
| 64-bit accuracy result).
| 
| But I don't believe that this is a problem - exp, sin etc don't really work for
| long double on MSVC either! And many implementations are not fully accurate -
| nor would one necessarily want to wait while they calculate to full accuracy.
| 
| The Standard does not, and should not, make any requirements about accuracy,
| memory size or speed.
| 
| So I feel they are panicing a bit.

Being one of the persons who raised the accuracy issue, I think I have
to say why.

The proposed mathematical functions are not there just for selling
compilers. They are there to serve *practical* purposes.  If there is
no accuracy guarantee, they don't worth to have -- they are already so
specialized.  LIA  has already set framework for those things.  Any
serious proposal to include such specialized functions need to pay
attention to those things.

-- Gaby