Bill Allombert on Wed, 26 Apr 2023 18:07:07 +0200
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Re: Factoring Carmichael Numbers
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- To: pari-dev@pari.math.u-bordeaux.fr
- Subject: Re: Factoring Carmichael Numbers
- From: Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>
- Date: Wed, 26 Apr 2023 18:05:51 +0200
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On Thu, Apr 20, 2023 at 11:59:43AM +0200, Paul Underwood wrote:
> Hi Bill,
>
> thank you for the explanation about factor().
>
> I have majorly increased the speed of my code, partly by incorporating
> factor() into it, but mostly by switching from expensive 2 selfridges Lucas
> sequences to 1 selfridge "Miller-Rabin" type calculations. The code now
> computes the maximum g.c.d of N with the "simple" algebraic factors of
> a^(n-1)-1.
By curiosity, why would you need to factor such numbers ? They are almost always
built from their factorisation.
You can probably speed up your code by skipping ispseudoprime until the factor
are fairly small (or fail to factor).
Cheers,
Bill.