Karim Belabas on Sat, 12 Oct 2024 18:08:20 +0200


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Re: computing all square root modulo a composite


* Karim Belabas [2024-10-12 18:05]:
> * Max Alekseyev [2024-10-12 17:56]:
> > As for the name, maybe sqrtall() ?
> 
> sqrtmod rather. Also note that function gives you all roots of any
> monic quadratic polynomial, not only square roots.
> 
> And it has a weird output format, which makes perfect sense if you
> think of it (you get the most precise mathematical information). It
> does not give you all solutions mod N but modulo M | N, whose
> lifts + k (N/M) mod N, 0 <= k < M are the solutions mod N.

Rather:

 lifts + k M mod N, 0 <= k < N/M are the solutions mod N.

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/