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Re: [Cado-nfs-discuss] FactorBaseFormat


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  • From: Emmanuel Thomé <emmanuel.thome@inria.fr>
  • To: cado-nfs-discuss@lists.gforge.inria.fr, Pierrick Gaudry <pierrick.gaudry@loria.fr>, Pankaj Charpe <charpe.pankajamol@gmail.com>
  • Subject: Re: [Cado-nfs-discuss] FactorBaseFormat
  • Date: Sat, 03 Feb 2018 13:00:10 +0100
  • List-archive: <http://lists.gforge.inria.fr/pipermail/cado-nfs-discuss/>
  • List-id: A discussion list for Cado-NFS <cado-nfs-discuss.lists.gforge.inria.fr>

Yes.
Actually log(p) would be less misleading than degree(p)...
E.


On February 3, 2018 11:21:24 AM GMT+01:00, Pierrick Gaudry
<pierrick.gaudry@loria.fr> wrote:
>Hi,
>
>From an old README file I have somewhere in an old directory:
>
> Factor base file format:
> ------------------------
>
> An entry is of the form:
>
> q:n1,n2: r1,r2,r3
>
> In the (frequent) case where n1,n2=1,0 this can be abridged with:
>
> q: r1,r2,r3
>
>Here, q is a irreducible or a irreducible power, ri are the
>corresponding
>roots and the contribution that must be subtracted at these positions
>is
> (n1-n2)*degree(p) (assuming smaller powers of this irreducible have
> alredy been taken care of). By position, we mean (a,b) such that a -
> b*ri = 0 mod q.
>
> The roots ri must be sorted in lexicographical order. If a root ri is
> greater or equal to q, it means that this is a projective root:
> subtracting q gives a root for the reciprocal polynomial (or
> equivalently, (1:(ri-q)) is the projective root).
>
> It is allowed to have several lines with the same q, but there must be
> only one line for a given (q,n1,n2) triple.
>
>Hopefully this is still valid in the version you are using.
>
>Regards,
>Pierrick
>
>On Sat, Feb 03, 2018 at 01:50:46PM +0530, Pankaj Charpe wrote:
>> Hi,
>> In factor base construction of cado-nfs we have this entry,
>> Factor Base format: q:n1,n2:r1,r2,r3
>>
>> Can you please explain me what is these n1 and n2 ?. I will be very
>> thankful to you.
>>
>>
>> Thanks & Regards
>> Pankaj charpe
>
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>
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Sent from my phone. Please excuse brevity and misspellings.




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