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 2010-11-24, 23:14 #34 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2×3×5×313 Posts Any known factor can be "found" with TF. Hint: check the structure of the TF savefile (it is only a few bytes), check the order of modular loops (this is a bit convoluted, TF is not sequential in every bitlevel), set up the good starting values and start TF with properly prepared savefile. (Another option is to recompile Prime95 to fine-tune it for this task.) If the machine was reliable, then try it again; you can even save some time by using Pminus1=1,2,23355961,-1,500,60000000 in worktodo.txt. It appears to work fine here. In that range, however, the numbers appear to have been tested to about B1=280000, B2=6370000, which is not enough to find this factor.
2010-11-25, 01:54   #35
cbright

Nov 2010

2 Posts

Quote:
 Originally Posted by Batalov Any known factor can be "found" with TF.
Heh, OK. Naturally you can 'find' it with just one modular exponentiation.

Quote:
 Originally Posted by Batalov If the machine was reliable, then try it again; you can even save some time by using Pminus1=1,2,23355961,-1,500,60000000 in worktodo.txt. It appears to work fine here.
Wait, how does that work? Won't you need 29^2<=B1 at least?

I'll see if I can repeat it, but that machine's motherboard died in 2008, and I don't know for sure which version of Prime95 I used. Now here's a case where we'd like to set the stage 2 starting point...

 2010-11-26, 07:15 #36 lorgix     Sep 2010 Scandinavia 3×5×41 Posts M2135957 has a factor: 1540376824575416172080436777449 101bit k=2^2*17*239*751*1399*6971*25033*121013 P-1
 2010-12-09, 18:13 #37 moebius     Jul 2009 Germany 22516 Posts M79804321 has a factor: 50705092580156382209 recent result from me, found at December, 8th 2010 Last fiddled with by moebius on 2010-12-09 at 18:30
 2010-12-09, 18:33 #38 ckdo     Dec 2007 Cleves, Germany 2·5·53 Posts Still hanging around with Miss February, are we?
2010-12-09, 19:05   #39
moebius

Jul 2009
Germany

54910 Posts

Quote:
 Originally Posted by ckdo Still hanging around with Miss February, are we?
No, Miss February should have been this one:

45980579 F-PM1 2010-01-26: 56670576085183271870247

 2010-12-09, 22:08 #40 Rhyled     May 2010 32×7 Posts Add 2 more ECM factors to the list: 2 ECM factors found a day apart, after 2 months of unsuccessful attempts M5457773 121234416604163371249241 M5456387 168049675942742879743
 2010-12-12, 18:02 #41 harlee     Sep 2006 Odenton, MD, USA 22·41 Posts Here are some of my recent finds, all found with P-1: M5568817 has a factor: 2580875798900949823169201 M5575387 has a factor: 24002502239318494727833 M5576897 has a factor: 2685038897114218470311471 M5579477 has a factor: 264051970555252442377 M5976967 has a factor: 200673846075753516727 M5975051 has a factor: 21173271365286672676124929 M5910731 has a factor: 41919405374519888959
2010-12-13, 00:31   #42
KingKurly

Sep 2010
Annapolis, MD, USA

33×7 Posts

Quote:
 Originally Posted by harlee Here are some of my recent finds, all found with P-1: M5568817 has a factor: 2580875798900949823169201 M5575387 has a factor: 24002502239318494727833 M5576897 has a factor: 2685038897114218470311471 M5579477 has a factor: 264051970555252442377 M5976967 has a factor: 200673846075753516727 M5975051 has a factor: 21173271365286672676124929 M5910731 has a factor: 41919405374519888959
Interesting you are in Odenton, I am in Annapolis. Lovely weather we have today, huh?

How does one perform P-1 on such "small" numbers? Is there an option, is it done by manual assignment, or do you simply select arbitrary numbers? (It is still amusing to me to consider a number like M5568817 to be small.)

 2010-12-13, 01:20 #43 harlee     Sep 2006 Odenton, MD, USA 22×41 Posts KinkKurly, The weather has been so lovely, I've been inside all day except I just had to pick up my son from work. At least it too warm to snow.... Ooooops, having flashbacks to last Feb. As for the assigments, I do a "Factoring limits" query the based on the exponent range, pick the ones with small B1 & B2 bounds, created a worktodo.txt and then register them via the server. Been doing this off and on for over a year now.
2010-12-18, 02:52   #44

"Richard B. Woods"
Aug 2002
Wisconsin USA

22×3×641 Posts

Quote:
 Originally Posted by harlee As for the assigments, I do a "Factoring limits" query the based on the exponent range, pick the ones with small B1 & B2 bounds, created a worktodo.txt and then register them via the server. Been doing this off and on for over a year now.
harlee,

Your brief explanation assumes that the reader knows how to avoid interfering with others' assignments. Please, instead, refer folks to this LMH sticky thread: "How to LMH using Prime95 v25.8 and PrimeNet v5" at http://mersenneforum.org/showthread.php?t=11308 and emphasize the importance of step 8.

Quote:
 Originally Posted by KingKurly How does one perform P-1 on such "small" numbers? Is there an option, is it done by manual assignment, or do you simply select arbitrary numbers? (It is still amusing to me to consider a number like M5568817 to be small.)
KingKurly,

Please see this LMH sticky thread: "How to LMH using Prime95 v25.8 and PrimeNet v5" at http://mersenneforum.org/showthread.php?t=11308

It explains how to obtain assignments outside the standard PrimeNet process, while making sure there's no interference or poaching. Do not skip step 8 of Uncwilly's procedure -- it is crucial to preventing accidental overlapping with other people's assignments!

But do use the standard manual PrimeNet assignment system for exponents in ranges PrimeNet is allowing to be handed out. IOW, first try to get manual assignment from PrimeNet for your range of interest, then if PrimeNet isn't handing out that range, release any unwanted exponents it did assign you, then go to carefully follow Uncwilly's procedure.

Last fiddled with by cheesehead on 2010-12-18 at 03:06

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