Re: t_PADIC to t_INTMOD and use of chinese()

[Max Alekseyev <maxale@gmail.com>]

Hi Karim,

I have already written my own code addressing those issues, but I believe it'd be beneficial to have built-in support for that conversion and application of chinese().

Hence, I posted those requests here.

Btw,

padic2mod(x) = Mod(x, x.mod);

looks a bit more straightforward.

Regards,

Max

On Fri, Feb 14, 2025 at 9:31 AM Karim Belabas <Karim.Belabas@math.u-bordeaux.fr> wrote:

* Max Alekseyev [2025-02-14 15:09]:
> dueHello,
>
> I have a couple of requests:
>
> 1) An easy way to convert t_PADIC to t_INTMOD, maybe extending Mod() to
> support a single argument of type t_PADIC, e.g. Mod(1 + O(5^2)) would
> produce Mod(1, 25).

  padic2mod(x) = Mod(x, x.p^padicprec(x, x.p));

  ? padic2mod(1+O(5^2))
  %1 = Mod(1, 25)

  ? padic2mod(5+O(5^2))
  %2 = Mod(5, 25)

  ? padic2mod(1/5+O(5^2))
  *** Mod: inconsistent  t_PADIC , t_INTMOD.

> 2) Extend chinese() to support t_PADIC arguments (still producing t_INTMOD).

  padicchinese(v) = chinese(apply(padic2mod, v))

  ? padicchinese([1 + O(5^2), 3 + O(3^3)])
  %3 = Mod(651, 675)

Cheers,

    K.B.
--
Pr. Karim Belabas, U. Bordeaux, Vice-président en charge du Numérique
Institut de Mathématiques de Bordeaux UMR 5251 - (+33) 05 40 00 29 77
http://www.math.u-bordeaux.fr/~kbelabas/