[Cado-nfs-discuss] Polyselect problem in cado-nfs-1.1
Zimmermann Paul
Paul.Zimmermann at loria.fr
Sat Mar 24 20:31:23 CET 2012
Dear Zachary,
thank you for your mail. I didn't know the "zero padding" trick to construct
fake numbers of 60 digits or more. Funny...
> In summary, although using CADO/NFS to factor numbers with less than
> 60 digits may not have value in /professional applications/, doing so
> may very well have pedagogical value. Can we say that is a fair
> statement, CADO guys?
you are right. However we prefer to spend our time improving CADO-NFS for
numbers of 100 digits or more, instead of providing support for tiny numbers.
> CADO-NFS is optimized only for numbers above 85 digits, and support
> is not even provided for factorization of integers with less than 60
> digits (since other factorization algorithms are much better for
> these smaller numbers). Also note that it is a good idea to first
> remove small prime factors with a different program that utilizes a
> suitable algorithm for that purpose (such as ECM---or ???) and only
> then to run CADO-NFS on any "hard" remaining factors which have at
> least 60 digits.
thank you, I have modified the README along those lines:
CADO-NFS is optimized only for numbers above 85 digits, and no support will
be provided for numbers of less than 60 digits. Note that it is a
good idea to remove small prime factors using special-purpose algorithms
such as trial division, P-1, P+1, or ECM, and use CADO-NFS only for the
remaining composite factor.
Paul
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