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 2018-05-30, 14:55 #441 hyramgraff   Jan 2018 1000012 Posts I was surprised to find such a large factor with settings optimized for 30 digit factors. Code: GMP-ECM 6.4.4 [configured with GMP 6.1.0, --enable-asm-redc] [ECM] Input number is 6791799153936500645432803709415674897403576115854345106509216573 02512210842714107504042514143509279143687934326862045806637465598577170030698639 39907063566032574234124386293757069836112420856904967943580197314005326553433926 69757816473416914726230827204181126950395601088979588731066439566823842928717186 75128298911533216869178867334130055945694895191331739721881 (363 digits) Run 401 out of 430: Using B1=250000, B2=128992510, polynomial Dickson(3), sigma=3019497377 Step 1 took 2780ms Step 2 took 1028ms ********** Factor found in step 2: 557172295660978462709725502307664383623870135 93731 Found probable prime factor of 50 digits: 55717229566097846270972550230766438362387013593731 Composite cofactor 1218976465059040443834739477156945548674792920302985605853429121627794 9623085784139709424457244324893107339172209402274275409256523706461433 7580941668601591059388584090906010550632184811055694891626199854079344 1844366357645987957465610950583807902371206167370270125577233154179128 6338464719210648028029318760713651 has 314 digits
 2018-06-11, 09:13 #442 fivemack (loop (#_fork))     Feb 2006 Cambridge, England 11001001101012 Posts Input number is 76983647872843791624151541906153913917977086313839027114971383467019508946343866342583615282406460808225869127591905065014787008215584264828981273123902994205217437194952904477939999664624747162863484885320070182586711670719715251 (230 digits) Run 11 out of 32: Using B1=1000000000, B2=19071176724616, polynomial Dickson(30), sigma=2807183577 Step 1 took 7728506ms Step 2 took 1153124ms ********** Factor found in step 2: 444391024295554825813920762553875384889500352609895126972409492191251 Found probable prime factor of 69 digits: 444391024295554825813920762553875384889500352609895126972409492191251 Composite cofactor 173234029636124329482413732384526787484660614027478215919523802481002152006501938783825536536976828897093688027674839882103830789172586815108211331791558012524001 has 162 digits
2018-06-11, 18:15   #443
hyramgraff

Jan 2018

3·11 Posts

Quote:
 Originally Posted by fivemack Input number is Found probable prime factor of 69 digits: 444391024295554825813920762553875384889500352609895126972409492191251
That's large enough to make it on the list of the top 50 factors: https://members.loria.fr/PZimmermann/records/top50.html

 2018-07-01, 16:05 #444 fivemack (loop (#_fork))     Feb 2006 Cambridge, England 645310 Posts 139!+1 done Code: Sun Jul 1 16:17:33 2018 p84 factor: 154026526536259486976791381709202414274307957213250722438177850806284297292352596891 Sun Jul 1 16:17:33 2018 p118 factor: 6944057549861420000506059176845705934485118493784592283341919973506171847370193586592773910514334148505693338642574449 Not sure this isn't the largest GNFS job using personal resources. 821 hours on 14 cores i9-7940X for the linear algebra on 44.48M density 136 matrix; about 20000 thread-days, mostly on E5-2650v1 processors, to get 978139469 relations.
2018-07-01, 16:09   #445
fivemack
(loop (#_fork))

Feb 2006
Cambridge, England

33×239 Posts

Quote:
 Originally Posted by hyramgraff That's large enough to make it on the list of the top 50 factors: https://members.loria.fr/PZimmermann/records/top50.html
Good point! I've mailed Paul

2018-07-01, 19:22   #446
sean

Aug 2004
New Zealand

227 Posts

Quote:
 Originally Posted by fivemack 139!+1 done
Very impressive, shame you didn't get a slightly larger penultimate.

 2018-07-04, 19:07 #447 chris2be8     Sep 2009 1001000101002 Posts Here's a nice split of (21623179^17-1)/218287827114501499853622 Code: prp51 factor: 400835974449507026429508363750399967684136291934989 prp51 factor: 564463714760965671472715787256458062957396312856251 Chris
 2018-07-25, 15:41 #448 chris2be8     Sep 2009 22·7·83 Posts My first job done with a septic. (10^105-10^90-10^74-1)/107 generates a nice poly: Code: n: 9345794392523355140186915887849532710280373831775700934579439252336448598130841121495327102803738317757 # m = 10^17 m: 1000000000000000 c7: 10 c6: -10 c5: -1 c0: -10 type: snfs And after a couple of hours: Code: p38 factor: 42430500173911639766168922724959195247 p66 factor: 220261235531454083548140762412574845378444054516121707598517853331 It would probably have been faster by GNFS since it's only a 103 digit number. But at least I can say I've done a septic. Chris
 2018-07-26, 19:18 #449 VBCurtis     "Curtis" Feb 2005 Riverside, CA 3×1,759 Posts ECM on 13*2^962-1, a C185: Using B1=150000000, B2=3973047228166, polynomial Dickson(30), sigma=1042721289 Step 1 took 1027041ms Step 2 took 541536ms ********** Factor found in step 2: 2519220864327285024701856003209805861449234353205468125651304153 Found probable prime factor of 64 digits: 2519220864327285024701856003209805861449234353205468125651304153 The c122 cofactor is composite: p64=1996676390473830958898711803711554458063469800085054040597619681 p59=18293875123847681477399988567617933809599560940077343333271
2018-07-26, 20:13   #450
ET_
Banned

"Luigi"
Aug 2002
Team Italia

22·7·173 Posts

Quote:
 Originally Posted by VBCurtis ECM on 13*2^962-1, a C185: Using B1=150000000, B2=3973047228166, polynomial Dickson(30), sigma=1042721289 Step 1 took 1027041ms Step 2 took 541536ms ********** Factor found in step 2: 2519220864327285024701856003209805861449234353205468125651304153 Found probable prime factor of 64 digits: 2519220864327285024701856003209805861449234353205468125651304153 The c122 cofactor is composite: p64=1996676390473830958898711803711554458063469800085054040597619681 p59=18293875123847681477399988567617933809599560940077343333271
That's huge!

 2018-07-31, 12:39 #451 Nooks   Jul 2018 19 Posts The last composite divisor of (34*10^227-61)/9 factorizes nicely as p81 * p81: Code: 52461733535023469582898980803025972072154673059207507371871956720157538\ 98046977445635531886836257491304639830851690564317257362489857828241541\ 1269306626660506087 == 10827123788671956642383008247645953132666017522133372016228954601610784\ 8102783919 * 48453988851510461382956631659231929664064303447082394831858420014654224\ 5073120073 Total factorization wall-clock time using the stdkmd-supplied SNFS polynomial and CADO-NFS was just shy of 3 days.

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