Re: [boost] [Regressions] Question for Mr Caleb Epstein.

From: Caleb Epstein (caleb.epstein_at_[hidden])
Date: 2005-03-22 16:14:07

On Wed, 16 Mar 2005 15:58:37 +0100, Hubert Holin <Hubert.Holin_at_[hidden]> wrote:

>       I am currently investigating some regressions for my quaternion
> and octonion libraries, which appear in the report of the tests you run
> under SunOS5.
> 
>       I have the feeling that for "long double" variables,
> numeric_limits<long double>::epsilon() returns the correct value, but
> standard transcendental functions (atan at least) behave as if their
> input were "double" and not "long double".
> 
>       Do you know if this is the case?

Sorry for the late reply.

I believe you're correct.  I don't see any prototypes for atan() that
take a long-double or that are templatized, but indeed
std::numeric_limits behaves correctly:

numeric_limits<double>: digits=53 digits10=15 max_exponent=1024
max_exponent10=308 min_exponent=-1021 min_exponent10=-307 radix=2
episilon=2.22045e-16
numeric_limits<long double>: digits=113 digits10=33 max_exponent=16384
max_exponent10=4932 min_exponent=-16381 min_exponent10=-4931 radix=2
episilon=1.92593e-34

-- 
Caleb Epstein
caleb dot epstein at gmail dot com