Re: [boost] [Math] boost::math::signbit returns false for -NAN

Subject: Re: [boost] [Math] boost::math::signbit returns false for -NAN
From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2009-03-15 20:38:32

Ping?
Regards Hartmut

> -----Original Message-----
> From: Hartmut Kaiser [mailto:hartmut.kaiser_at_[hidden]]
> Sent: Wednesday, March 11, 2009 8:35 AM
> To: 'boost_at_[hidden]'
> Cc: 'John Maddock'
> Subject: [Math] boost::math::signbit returns false for -NAN
> 
> Hi all,
> 
> the boost::math::signbit function in trunk fails for an argument of -
> NAN.
> 
> #include <boost/math/special_functions/sign.hpp>
> 
> int main()
> {
>     using boost::math::signbit;
>     BOOST_ASSERT(signbit(-std::numeric_limits<double>::quiet_NaN()));
>     return 0;
> }
> 
> I'd expect to get a '1' back, but the function returns zero and the
> assertion fails. I know it worked while using Jon Rade's floating point
> utilities library from the vault. Does this have been integrated?
> 
> Regards Hartmut
>