gmp 4.1 documentation improvement suggestions

[Paul Zimmermann]

   > I think the manual is clear (well, almost...); it says:
   > 
   >     The precision of a calculation is defined as follows: Compute
   >     the requested operation exactly (with ``infinite precision''),
   >     and round the result to the destination variable precision with
   >     the given rounding mode.

   It seems to me that these two usages of "precision" are different.

   I'd suggest that the paragraph

   > > "...if two low-precision numbers of nearly equal magnitude are added, 
   > > the precision of the result will be limited to what is required to 
   > > represent the result accurately."

   be reworded as something like

   > > "...if two low-precision numbers of nearly equal magnitude are added, 
   > > MP will not perform more operations than required to 
   > > compute the result accurately, even if high precision is set 
   > > in the result. In this case the high precision of the resulting 
   > > mpfr object will not reflect the actual low precision of this
   > > calculation."

Yes that was indeed unclear (and even partly wrong). I suggest rewriting
both paragraphs in one:

   The semantics of a calculation in MPFR is specified as follows: Compute the
   requested operation exactly (with ``infinite accuracy''), and round the result
   to the precision of the destination variable, with the given rounding mode.
   The MPFR floating-point functions are intended to be a smooth extension
   of the IEEE P754 arithmetic. The results obtained on one computer should not
   differ from the results obtained on a computer with a different word size.

Is that ok?

Paul