proposal to change the return type/value of mpz_primorial_ui

[Shane Neph]

First, thank you for your work.  I will be using it.  I'd like to see
it or similar become part of the GMP library.

I also would like to see the primordial function return that same
value because it knows the value.

In my work, I use primordial in ways similar to factorials, and I use
it over a factorial because it simply grows faster.

Your work is appreciated here, Marco.

On Thu, Nov 11, 2021 at 1:54 PM Marco Bodrato <bodrato at mail.dm.unipi.it> wrote:
>
> Ciao,
>
> Il 2021-11-08 18:57 Marco Bodrato ha scritto:
> > I got inspired by a piece of code that Seth Troisi sent a couple of
> > years ago and I wrote a gmp_pi_ui(n) function with two variants, a
> > trivial one (it calls gmp_primesieve) and an implementation of the
> > Legendre strategy.
> >
> > I attach it for comments. Compiled with -DMAIN it prints the number of
> > primes up to increasing powers of two. On my computer, with small
> > ranges it is slower than GP/Pari, for large ranges, it is faster...
>
> I checked the results against https://oeis.org/A007053 and
> https://oeis.org/A006880 up to 2^47. Everything seems correct... Of
> course, for "large" (>2^32) values it is a slow function.
>
> It currently takes an ui for the argument. But it should not be
> impossible to implement it also for values larger than 32 bits on
> 32-bits CPUs... Is it worth trying?
>
> Ĝis,
> m
>
> --
> http://bodrato.it/papers/