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 2014-05-13, 19:41 #1 XYYXF     Jan 2005 Minsk, Belarus 19016 Posts Some ECM pre-factoring is necessary to remove small factors before running an SNFS job, stopping when the expected factor size is about 22% of SNFS difficulty. There we collect targets which are ready for SNFS. If you see a composite which survived enough ECM tests and has a small cofactor, feel free to add it there. A polynomial construction is also appreciable :-) Last fiddled with by XYYXF on 2016-02-14 at 19:39 Reason: updated
2014-05-15, 23:56   #2
fivemack
(loop (#_fork))

Feb 2006
Cambridge, England

2×7×461 Posts

Quote:
 Originally Posted by XYYXF C250_128_89, 21000 curves at B1 = 260M, difficulty 250 (2104)6 + 15842*(8921)6 = 6 * C250 C254_127_102, 21000 curves at B1 = 260M, difficulty 256 (12717)6 + 102*(10221)6 = 103 * C254
I'd expect these to take 15k - 25k thread-hours each (depending on the age of the machine you use), so they're non-trivial commitments unless you've got access to a cluster.

Last fiddled with by XYYXF on 2015-06-21 at 17:47

 2014-12-05, 22:45 #3 XYYXF     Jan 2005 Minsk, Belarus 6208 Posts C251_126_103, 20000 curves at B1 = 260M Sextic (difficulty 254): 126*(12617)6 + (10321)6 = 635 * C251
2015-04-13, 20:02   #4
XYYXF

Jan 2005
Minsk, Belarus

1100100002 Posts

All are factored (or reserved) except for
Quote:
 Originally Posted by XYYXF C208_133_43, 7600 curves at B1 = 43M Sextic (difficulty 218): 43*(4322)6 + 133*(1337)6 = 16248239480 * C208

 2015-06-16, 20:35 #5 fivemack (loop (#_fork))     Feb 2006 Cambridge, England 2·7·461 Posts I'll take C208_133_43
 2015-06-21, 23:15 #6 XYYXF     Jan 2005 Minsk, Belarus 19016 Posts (reserved) C162_123_58, 7600 curves at B1=43M Sextic (difficulty 217): 195112*(5820)6 + 228886641*(1239)6 = 50002164960288875248029920622180294596898636638194696301 * C162 C162_144_37, 7600 curves at B1=43M, perhaps needs some curves at B1=110M Sextic (difficulty 226): (3724)6 + 144*(1212)6 = 18503369959822517532081459390273377279584717590723349144530544225 * C162 These two are currently the smallest composites in the project (except for C160_146_39 which is already under SNFS by Sean Wellman). (reserved) C166_117_76, 7600 curves at B1=43M Sextic (difficulty 220): 438976*(7619)6 + 257049*(325*1312)6 = 3687149743256520163799275205528985260542672222364271457 * C166 Last fiddled with by XYYXF on 2015-06-28 at 06:59
 2015-06-22, 13:32 #7 fivemack (loop (#_fork))     Feb 2006 Cambridge, England 2·7·461 Posts I'll take C162_123_58; however, it is definitely a GNFS number (polynomial from five minutes search sieves 60% faster than the SNFS sextic). The other C162 is an SNFS number, since the coefficients of the SNFS polynomial are so much smaller than for 123_58 Last fiddled with by fivemack on 2015-06-22 at 15:26
 2015-06-22, 19:39 #8 XYYXF     Jan 2005 Minsk, Belarus 24×52 Posts That's how the coefficients affect the sieving speed :)
 2015-06-28, 06:53 #9 XYYXF     Jan 2005 Minsk, Belarus 19016 Posts C165_125_71, 18000 curves at B1=110M Sextic (difficulty 234): (7121)6 + 8875*(535)6 = 705802046969421619725838846919055406138655378181220926249900100315924 * C165 Might be GNFS as well...
 2015-06-28, 16:56 #10 fivemack (loop (#_fork))     Feb 2006 Cambridge, England 2·7·461 Posts I will throw 100 CPU-hours at polynomial selection and report back if it gets good enough, but at the moment I suspect 125,71 is SNFS.
 2015-06-30, 08:50 #11 fivemack (loop (#_fork))     Feb 2006 Cambridge, England 2×7×461 Posts I'll take C165_125_71 for GNFS Last fiddled with by fivemack on 2015-06-30 at 10:04

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