Discussion related to cado-nfs

[Pierrick Gaudry <pierrick.gaudry@loria.fr>]

Definitely a bug. Thanks for reporting!

This is not the first time we have this kind of problem. Very annoying...

I've opened an issue on gitlab and will have a look in the next few days.
https://gitlab.inria.fr/cado-nfs/cado-nfs/-/issues/30012

Regards,
Pierrick

On Wed, Mar 17, 2021 at 04:08:28AM +0000, Robert Balfour wrote:
> Dear all,
> 
> I've found a case where las produces a relation where one of the factors is
> the square of a prime. This was picked up by msieve filtering; I haven't
> tried CADO filtering on this dataset. Is this expected behaviour or a bug?
> 
> The relation is:
> 2511674949,47519:2,2,2,2,2,2f,3d,359,587b,253c69,91b17f,107ef81:2,2,2,3,3,3,5,5,7,b,59,2f41,2fa5,25a29,cb45f,1b1a87,b35a35,4dcef0f,146baa23
> where 0x107ef81 = 17297281 = 4159^2 = (0x103f)^2.
> This number was correctly factored as 103f,103f in other relations. Both
> the latest revision and revision dbdb6eb fail to split 107ef81 in this
> relation.
> 
> Number and polynomials are:
> n:
> 295050353250969949275638952676190854099143197890400946947699613474117769236877135613197953075573082247700069221444132611618998393933743532422465257
> # f(x) =
> -3003840*x^5+957820236360*x^4+1389898521545792753*x^3-322967502530987876578342*x^2-83629655633967437555949973621*x+3423180581131422410334670590644010
> # g(x) = 164665144403235916141*x-15113634718431527142364842527
> 
> Parameters used for sieving:
> tasks.I = 14
> tasks.qmin = 4000000
> tasks.lim0 = 13000000
> tasks.lim1 = 25000000
> tasks.lpb0 = 29
> tasks.lpb1 = 29
> tasks.sieve.mfb0 = 54
> tasks.sieve.mfb1 = 57
> tasks.sieve.lambda0 = 2.06
> tasks.sieve.lambda1 = 2.165
> tasks.sieve.ncurves0 = 15
> tasks.sieve.ncurves1 = 20
> tasks.sieve.qrange = 10000
> tasks.sieve.adjust_strategy = 2
> tasks.sieve.rels_wanted = 60000000
> 
> The relation was found in the range 11750000-11760000 (q=11754037).
> 
> Best regards,
> Robert Balfour