# gmp 4.1 documentation improvement suggestions

**Paul Zimmermann
**
Paul.Zimmermann@loria.fr

*Thu, 12 Dec 2002 16:32:20 +0100*

> 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