mersenneforum.org  

Go Back   mersenneforum.org > Factoring Projects > Factoring

Reply
 
Thread Tools
Old 2010-03-11, 06:05   #12
Andi47
 
Andi47's Avatar
 
Oct 2004
Austria

2·17·73 Posts
Default

Quote:
Originally Posted by R. Gerbicz View Post
Code:
48 c256
p-1: B1=1e9, B2=1e14, no factor.
Andi47 is offline   Reply With Quote
Old 2010-03-11, 16:28   #13
grandpascorpion
 
grandpascorpion's Avatar
 
Jan 2005
Transdniestr

7678 Posts
Default

Very exciting stuff
grandpascorpion is offline   Reply With Quote
Old 2010-03-11, 17:06   #14
fivemack
(loop (#_fork))
 
fivemack's Avatar
 
Feb 2006
Cambridge, England

11000111011112 Posts
Default

Will try to run a large number of curves at 43e6 while I'm on vacation (set off 16 jobs at 1e8 but this made the machine swap beyond the point of usability).
fivemack is offline   Reply With Quote
Old 2010-03-11, 17:07   #15
R.D. Silverman
 
R.D. Silverman's Avatar
 
Nov 2003

22×5×373 Posts
Default

Quote:
Originally Posted by fivemack View Post
Will try to run a large number of curves at 43e6 while I'm on vacation (set off 16 jobs at 1e8 but this made the machine swap beyond the point of usability).
Ask Bruce to take a whack at it.
R.D. Silverman is offline   Reply With Quote
Old 2010-03-11, 17:34   #16
axn
 
axn's Avatar
 
Jun 2003

134616 Posts
Default

2000 curves completed @ 3e6.

currently running 43e6
axn is offline   Reply With Quote
Old 2010-03-12, 16:45   #17
bdodson
 
bdodson's Avatar
 
Jun 2005
lehigh.edu

210 Posts
Default

Quote:
Originally Posted by R.D. Silverman View Post
Ask Bruce to take a whack at it.
I've spent the past 10-days-or-so "whack"ing on the current NFS@Home
reservation, with another 10-days-or-so left to go. I recently completed
p55-tests on the Cunninghams from c190-c209.99 (either 7t50 or 6t50,
depending on the difficulty); and am currently working toward t55's on
c210-c233, in between NFS@Home and Batalov+Dodson numbers. I'm also
making a lower priority run through c234-c289.487 plus the 2- and 2+
numbers (not including 2LMs) the rest of the way up, through C355; working
toward 3t50. Likely enough to keep our cpus busy the rest of 2010.

Almost all curves are with p60-optimal limits (B1=26e7=260e6, gmp-ecm
default B2); except for a few xp's with just 500Mb available for condor jobs,
running p55-limits.

Uhm. This is a c256 gnfs number, currently in testing for p50's? I'm having
some trouble seeing this as the first gnfs number above 768-bits
(232-digits). -Bruce
bdodson is offline   Reply With Quote
Old 2010-03-12, 18:53   #18
Batalov
 
Batalov's Avatar
 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

2×37×127 Posts
Default

By definition, the single smallest factor is enough to continue the sequence.

But from the current status, it is going to take a leap of faith, if (e.g.) a p54 factor is found. This iteration may need a lot of subsequent ECM to minimize the probability that that would be the smallest factor (and still not remove the doubt entirely). Tough!

(The same was or still is the case on the -1 analog of EM sequence, right? I don't see the p51 there, it was mentioned earlier in this thread. Sloane's A005265)
Batalov is offline   Reply With Quote
Old 2010-03-12, 18:59   #19
10metreh
 
10metreh's Avatar
 
Nov 2008

91216 Posts
Default

Remember that if we do find a factor with ECM and the cofactor is composite, we will still have to factor the cofactor to check that the ECM factor is indeed the smallest prime factor.
10metreh is offline   Reply With Quote
Old 2010-03-12, 19:03   #20
bdodson
 
bdodson's Avatar
 
Jun 2005
lehigh.edu

40016 Posts
Default

Quote:
Originally Posted by Batalov View Post
By definition, the single smallest factor is enough to continue the sequence.

But from the current status, it is going to take a leap of faith, if (e.g.) a p54 factor is found. This iteration may need a lot of subsequent ECM to minimize the probability that that would be the smallest factor (and still not remove the doubt entirely). Tough! ...
A p54 would go a long way towards making a composite cofactor nearer
to our current gnfs range; or perhaps better yet, leave a large prime
cofactor. I'd consider running a second t55, once the first one fails.
So somewhere past the effort of 4 t50's (with t55 = c. 5.7*t50?). Finding
a p53/p54 isn't among my objectives, unless it's from a Cunningham.
Once p53/p54 is unlikely, EM48 is as good as any other candidate for
finding a nice p60+ factor (which would get recorded, for a while at least
.... uhm, maybe p62+, Brent's list of p60+ is already past 10). -Bruce
bdodson is offline   Reply With Quote
Old 2010-03-12, 20:03   #21
CRGreathouse
 
CRGreathouse's Avatar
 
Aug 2006

135418 Posts
Default

10,000 curves done at 11M, so the smallest factor should be at least 45 digits. Just for fun, I'm running some curves at 260M... but even if there was a factor in the appropriate range, there's only about a 1-(1-1/52000)^{1000}\approx2% chance I'd find it with as few curves as I'm running.

Last fiddled with by CRGreathouse on 2010-03-12 at 20:25
CRGreathouse is offline   Reply With Quote
Old 2010-03-12, 20:08   #22
Andi47
 
Andi47's Avatar
 
Oct 2004
Austria

2×17×73 Posts
Default p+/-1

Has any p+/-1 been done besides my p-1 with B1=1e9, B2=1e14?

For p-1 I have extended B1 to 1e10 (no factor with B2=1e13) and I'm currently extending it to B1=2e10 or even further (maybe 5e10).

As soon as my laptop will get free (currently running a GNFS-job, will be finished around Wednesday) I will do B2=1e15 for whatever B1 I will have reached by then. (B2=1e18 will be left to someone with a machine with 8 cores and 32+ GB RAM)

Last fiddled with by Andi47 on 2010-03-12 at 20:08
Andi47 is offline   Reply With Quote
Reply

Thread Tools


All times are UTC. The time now is 20:42.

Wed Apr 21 20:42:47 UTC 2021 up 13 days, 15:23, 0 users, load averages: 2.40, 2.20, 1.98

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.