Emantissapation

[Jim White]

> Date: Thu, 29 Nov 2007 11:06:11 -0600

> From: cino hilliard <hillcino368 at hotmail.com>
>> from Wolfram:
> 
> Mantissa 
> For a real number , the mantissa is defined as the
> positive fractional part. 
>
> For example,  for real 3.14159 , the mantissa is
> 0.14159. 

This eyebrow-raising definition does correctly quote
the source page
(http://mathworld.wolfram.com/Mantissa.html ), but
this is not one of Eric's better efforts!

The definition fails to point out the rather crucial
point that the number "x" referred to there is assumed
to be a LOGARITHM representing (in some base B) the
real number y = B^x.

A careful reading of the GMP manual (sections 17.1 and
17.3) should explain what I mean by "the mantissa is
an integer", why that is indeed so, and how the
"algorithm" of mpf_out_raw is simply a consequence of
this elementary property.

Cheers

Jim White
MSI, ANU