mpz_prevprime

[Seth Troisi]

There doesn't seem to be any objection to this change and it has good tests.
I think the macro can be improved (and potentially expanded to
mpz_nextprime_stride) but I hope that can happen after an initial version
is checked in.
committing this would also allow me to improve my implementation of
mpz_primepi which I'm energized to get pulled.

pulling the patch for t-nextprime.c proposed in
https://gmplib.org/list-archives/gmp-devel/2020-January/005672.html
should probably be done first to simplify the testing here, I'm happy to
resolve the merge conflict and propose a new patch
once that's done


On Sat, Nov 16, 2019 at 1:09 AM Marco Bodrato <bodrato at mail.dm.unipi.it>
wrote:

> Ciao,
>
> Il 2019-09-03 08:41 Seth Troisi ha scritto:
> > 1. s->reps next_primes chained (next_prime(p, p); next_prime(p, p);)
>
> > Currently it takes about 20 seconds to test -s 16-128, and 15 minutes
> > to test -s 16-1028
> > with -t 1.04 the resulting graph is much smoother than the old graph.
>
> Also your proposed patch for tune/speed, to support mpz_nextprime, was
> committed.
>
> https://gmplib.org/repo/gmp/rev/8aa3b936c707
>
> Ĝis,
> m
>