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-   -   Found a factor? Enshrine, embalm and entomb it here! (RU "Выкрасить и выбросить")) (https://www.mersenneforum.org/showthread.php?t=13977)

 Batalov 2010-11-24 23:14

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
[FONT=Arial Narrow]Pminus1=1,2,23355961,-1,500,60000000[/FONT]
in worktodo.txt. It appears to work fine here.

In that range, however, the numbers appear [URL="http://www.mersenne.org/report_exponent/?exp_lo=23355901&exp_hi=23356061&B1=Get+status"]to have been tested[/URL] to about B1=280000, B2=6370000, which is not enough to find this factor.

 cbright 2010-11-25 01:54

[QUOTE=Batalov;238567]Any known factor can be "found" with TF. [/QUOTE]
Heh, OK. Naturally you can 'find' it with just one modular exponentiation.

[QUOTE=Batalov;238567]If the machine was reliable, then try it again; you can even save some time by using
[FONT=Arial Narrow]Pminus1=1,2,23355961,-1,500,60000000[/FONT]
in worktodo.txt. It appears to work fine here.[/QUOTE]
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...

 lorgix 2010-11-26 07:15

M2135957 has a factor: 1540376824575416172080436777449

101bit

k=2^2*17*239*751*1399*6971*25033*121013

P-1

 moebius 2010-12-09 18:13

M79804321 has a [COLOR=Red]factor[/COLOR]: 50705092580156382209

recent result from me, found [SIZE=2]at December, 8th 2010[/SIZE]

 ckdo 2010-12-09 18:33

Still hanging around with Miss February, are we? :big grin:

 moebius 2010-12-09 19:05

[QUOTE=ckdo;240974]Still hanging around with Miss February, are we? :big grin:[/QUOTE]

No, Miss February should have been this one:

[SIZE=2]45980579 [/SIZE][SIZE=2]F-PM1 [/SIZE][SIZE=2]2010-01-26: 56[/SIZE][SIZE=2]670576085183271870247[/SIZE]

 Rhyled 2010-12-09 22:08

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

 harlee 2010-12-12 18:02

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

 KingKurly 2010-12-13 00:31

[QUOTE=harlee;241438]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[/QUOTE]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.)

 harlee 2010-12-13 01:20

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.

[QUOTE=harlee;241511]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.[/QUOTE]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: "[B]How to LMH using Prime95 v25.8 and PrimeNet v5[/B]" at [URL]http://mersenneforum.org/showthread.php?t=11308[/URL] and emphasize the importance of step 8.

[QUOTE=KingKurly;241505]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.)[/QUOTE]KingKurly,

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

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

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 [I]carefully[/I] follow Uncwilly's procedure.

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