Contributing to GMP

Marco Bodrato bodrato at
Wed Feb 26 10:13:08 UTC 2020


Il Lun, 24 Febbraio 2020 2:51 pm, Marc Glisse ha scritto:
> On Mon, 24 Feb 2020, Marco Bodrato wrote:

>> Of course, if you don't care to obtain sqrt(9/49) = 3/7 or anything
>> different...
> If you are going to approximate sqrt(2) with a rational, you probably
> don't care that much about getting exactly 3/7 either.

True, but 3/7 is more efficient for the following computations :-)

>> Well, also mpz_sqrt is not exact :-)
> I see it more like division: you can see integer division as inexact, or
> as a different operation (division with remainder).

That's an interesting point of view.

>> But of course, with mpq, we can decide how to approximate.
> By the way, maybe the function could return a bool (exact or not) or
> {-1,0,+1} to say in which direction it approximated.

That's the easy part. But one may also want to let the caller decide the
desired direction of approximation. Efficiency is much more tricky.

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