Msieve doesnt print found pre-factor

Karl M Johnson · 2010-06-09, 08:00

Been playing with Msieve today.
Decided to factor this number:

Code:

42734883900163624857094621807876721359795483286209312811244843209772450004974556754862199091514562767677661120667719181850740747700635351096238640647281624823627777

Now, when I launch Msieve with "-e" flag, it says:

Code:

Wed Jun 09 10:54:17 2010  
Wed Jun 09 10:54:17 2010  
Wed Jun 09 10:54:17 2010  Msieve v. 1.45
Wed Jun 09 10:54:17 2010  random seeds: f0536280 4bb61f69
Wed Jun 09 10:54:17 2010  factoring 42734883900163624857094621807876721359795483286209312811244843209772450004974556754862199091514562767677661120667719181850740747700635351096238640647281624823627777 (164 digits)
Wed Jun 09 10:54:19 2010  searching for 15-digit factors
Wed Jun 09 10:54:19 2010  searching for 20-digit factors
Wed Jun 09 10:54:20 2010  ECM stage 1 factor found
Wed Jun 09 10:54:26 2010  searching for 25-digit factors
Wed Jun 09 10:55:50 2010  searching for 30-digit factors

It found one factor, but doesnt want to print/report it.How come?
Can this be fixed?
Or can I somehow find out this factor?

debrouxl · 2010-06-09, 10:48

AFAICS, msieve prints the factor if you abort it

Code:

$ ~/msieve/msieve -e -v 42734883900163624857094621807876721359795483286209312811244843209772450004974556754862199091514562767677661120667719181850740747700635351096238640647281624823627777


Msieve v. 1.46
Wed Jun  9 12:47:29 2010
random seeds: f9a79a0c fc161bad
factoring 42734883900163624857094621807876721359795483286209312811244843209772450004974556754862199091514562767677661120667719181850740747700635351096238640647281624823627777 (164 digits)
searching for 15-digit factors
P+1 stage 1 factor found
searching for 20-digit factors
searching for 25-digit factors
ECM stage 1 factor found
^C of 214 curves
received signal 2; shutting down
p1 factor: 7
p2 factor: 11
p3 factor: 349
p4 factor: 5701
p5 factor: 57131
p10 factor: 1340604403
prp18 factor: 161854686723721471
c125 factor: 22501817005493334348523392493796091936051703811945995046532087369436635411582778638204076829552998288737677246374840629189083
elapsed time 00:00:20

current factorization was interrupted

Karl M Johnson · 2010-06-09, 10:59

Great googaly-moogaly, you're right!
It's all about the verbose flag.
Thanx a million, Debrouxl.

Edit:No it's not.
It has something to do with shutting down Msieve too early.

Mini-Geek · 2010-06-09, 11:55

It probably doesn't print the factor immediately because it's trying to factor the cofactor first, get the whole factorization, then tell you that.

jasonp · 2010-06-09, 12:00

Yes, by default it will not print any factors until the input is completely split. That's clearly a problem if you only want small factors; an exception is if you hit Ctrl-C while ECM is running, in that case msieve will quit and print all factors found plus any remaining composites.

Karl M Johnson · 2010-06-10, 12:51

Ok, after some hours of polyselecting on Msieve, I got this poly(already converted for GGNFS script):

Code:

n: 22501817005493334348523392493796091936051703811945995046532087369436635411582778638204076829552998288737677246374840629189083
skew: 1257698.40
Y0 -1903681667229673635651352
Y1: 20794241923391
c0 -353322081250584758714689607870235
c1: 3095563285919716633384764648
c2 -3557200175395056994975
c3 -4602443679682184
c4: 652887174
c5: 900
type: gnfs

However, when I try to feed it to factmsieve.py, it prints this error:

Code:

Error: poly coefficients have a common factor commonfac. Please divide it out

Now, what shall I do?

Batalov · 2010-06-10, 19:43

Put the missing colons in the file. Do you see the missing ":" after Y0, c0, etc?
That's the only problem.

Karl M Johnson · 2010-06-10, 20:45

Always something small!

Thanks for pointing out, Batalov.

2010-06-09, 10:59	#3
Karl M Johnson Mar 2010 3·137 Posts	Great googaly-moogaly, you're right! It's all about the verbose flag. Thanx a million, Debrouxl. Edit:No it's not. It has something to do with shutting down Msieve too early. Last fiddled with by Karl M Johnson on 2010-06-09 at 11:05

2010-06-09, 12:00	#5
jasonp Tribal Bullet Oct 2004 3,541 Posts	Yes, by default it will not print any factors until the input is completely split. That's clearly a problem if you only want small factors; an exception is if you hit Ctrl-C while ECM is running, in that case msieve will quit and print all factors found plus any remaining composites. Last fiddled with by jasonp on 2010-06-09 at 12:01

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2010-06-09, 11:55	#4
Mini-Geek Account Deleted "Tim Sorbera" Aug 2006 San Antonio, TX USA 17×251 Posts	It probably doesn't print the factor immediately because it's trying to factor the cofactor first, get the whole factorization, then tell you that.

2010-06-10, 19:43	#7
Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 3⁶·13 Posts	Put the missing colons in the file. Do you see the missing ":" after Y0, c0, etc? That's the only problem.

2010-06-10, 20:45	#8
Karl M Johnson Mar 2010 3×137 Posts	Always something small! Thanks for pointing out, Batalov.