From: Johan Råde (rade_at_[hidden])
Date: 2008-02-27 10:32:37
> There is one other useful function worth having IMO:
>
> template <class T>
> int sign(T x);
>
> returns 0 (x is zero), +1 (x is > 0) or -1 (x is < 0). This is trivial to
> implement (lot's of old C code - for example the Numerical Recipies stuff -
> implement this as a helper macro), and there's an undocumented version
> currently in Boost.Math. Is this worth integrating with Johan's code? I've
> found it quite useful in Boost.Math from time to time.
What should this function return for a NaN?
--Johan