From: GOTO Kentaro <gotoken@...>
Date: 2004-10-13T23:33:53+09:00
Subject: Re: "nan".to_f ?

In message Re: "nan".to_f ?
  on Wed, 13 Oct 2004 21:38:22 +0900, Yukihiro Matsumoto wrote:

> Although we can tell whether a float value is NaN by using isnan(),
> but as far as I know there's no portably way to generate NaN.  I think
> it's not guaranteed that 0.0/0.0 generate NaN.

  def aNaN
    s, e, m = rand(2), 2047, rand(2**52-1)+1
    [sprintf("%1b%011b%052b", s,e,m)].pack("B*").unpack("G").first
  end

I believe this will generate NaN on environments where 
pack/unpack works and NaN exists. 


Gotoken