Timothy.Musson@zin-tech.com (Timothy A. Musson) writes:
> Yes. A two-second SWAG tells me that any number that is not a power of two
> (not of the form 2^N) could not be expressed exactly in floating point
> representation, if anyone that really knows the answer would like to give
> more input, I'd be happy to read. 

6 is not a power of 2 but can be expressed exactly.  ;-)

I think the concept you almost put your finger on is that the number
that is to be expressed must be expressible as the sums of various
powers of two (with negative powers of two also allowed).

-wolfgang
-- 
       Wolfgang Rupprecht <wolfgang+gnus@dailyplanet.wsrcc.com>
		    http://www.wsrcc.com/wolfgang/
Coming soon: GPS mapping tools for Open Systems. http://www.gnomad-mapping.com/