On Sat, 16 Dec 2006, Les wrote:
On Fri, 2006-12-15 at 19:44 -0500, Mike - EMAIL IGNORED wrote:
How do I find the max double on my FC4?
Thanks,
Mike.
If you are discussing the size of the double precision number, you can
look in the Math.h. The exact number will depend on the encoding and
These values are in float.h, not math.h.
that is separate from the generic language specification. Most PC's
rely on straight binary encoding, and so would have a range of -2e48 to
(2e48-1) with a characteristic in binary of +32767 to -3768. The
remaining bit sets the sign for the characteristic.
Hmm. If the values in float.h are to be believed, doubles appear to have
53-bit mantissas and exponents ranging from -1021 to 1024. Long doubles
have 64-bit mantissas and exponents ranging from -16381 to 16384. Each
representation also includes a sign bit for the mantissa.
Most PCs rely on IEEE-754 representation for floats. I think the
remaining exponent bit patterns indicate IEEE-754 states like NaN,
INFINITY, DENORM, etc. See http://en.wikipedia.org/wiki/IEEE_754 for an
intro to the gory details.
Regards,
Les H
--
Matthew Saltzman
Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs
