From: Peter Bartlett (pete_at_[hidden])
Date: 2008-02-27 10:40:52
Quoting Johan Råde <rade_at_[hidden]>:
>> 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?
A NaN?