[Cado-nfs-discuss] FactorBaseFormat

Emmanuel Thomé emmanuel.thome at inria.fr
Sat Feb 3 13:00:10 CET 2018

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

On February 3, 2018 11:21:24 AM GMT+01:00, Pierrick Gaudry <pierrick.gaudry at loria.fr> wrote:
>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
>roots and the contribution that must be subtracted at these positions
>    (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.
>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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