mersenneforum.org - P-1 factoring anyone?

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- - P-1 factoring anyone? (https://www.mersenneforum.org/showthread.php?t=11101)

Actually James, if your bounds are in general a little low, Prime95 calculates bounds using LL tests saved slightly higher than 2 for erroneous tests.

[QUOTE=flashjh;291683]I have plenty of memory but so far no exponent has gone above 960 relative primes. I'm sure it's been discussed, but what is Prime95s max # of relative primes right now?[/QUOTE]Those number come from [url=http://www.mersenneforum.org/showthread.php?t=14562&page=2]this thread[/url], especially starting around post #29. The largest number of RPs I've seen processed is 1440 but that was a rare (unique?) occurrence.

[QUOTE=James Heinrich;291698]Those number come from [URL="http://www.mersenneforum.org/showthread.php?t=14562&page=2"]this thread[/URL], especially starting around post #29. The largest number of RPs I've seen processed is 1440 but that was a rare (unique?) occurrence.[/QUOTE]

Cool, I guess we'll see when [URL="http://www.mersenneforum.org/showthread.php?p=291650#post291650"]this baby[/URL] gets to stage 2.

It's been so long since my main P-1 machine found a factor that I ran a known-factor exponent through it last night just to make sue it was still working - luckily it found the factor. Guess I just have a really dry set of P-1 numbers right now.

[QUOTE=James Heinrich;291659]No, there's room for you to beat me: the largest FFT in Prime95 (32M) is capped at M596,000,000 so that means [URL="http://mersenne-aries.sili.net/M595999993"][COLOR=#0066cc]M595,999,993[/COLOR][/URL] is the largest candidate. But, being the largest candidate, it's already [URL="http://v5www.mersenne.org/report_exponent/?exp_lo=595999993"][COLOR=#0066cc]had some P-1 attention[/COLOR][/URL] from at least 3 users, most recently [I]B1=4479490, B2=107507760 by "Åke Tilander" on 2011-12-03[/I].[/QUOTE]

[QUOTE=flashjh;291683]Anyway, Åke Tilander has that assignment out for LL testing as of 29 Feb 2012. I would hate to P-1 it and find a factor while it's assigned ;)[/QUOTE]

Well, for me its no problem if anyone would like to try to P-1 M595999993 to an even higher level. It would be difficult though to select the boundaries in the most reasonable way in order not to redo the same work again. I think though that the P-1 I already did is more or less to the level which is considered as reasonable. The assignment gave a credit of 403.6681 Ghz-Days. I had to "little" memory (24 GB) for Brent-Suyama to kick in. The largest exponent I have done with B-S is M397626811 (E=6).

M595999993 is the largest exponent prime95 can handle at the moment. I did the P-1 in order to test the capabilities of the program. Sometimes weaknesses in programs appears when you use them close to their limits.

So anyone can feel free to do more P-1s on M595999993 or to trial factor it beyond ^80 or even try to do a LL (double-check). Please post here if you would like to do more work on M595999993 so that we don't do the same work.

If someone wants to do a LL double-check please use in "prime.txt":

ResultsFileIterations=20000000
InterimFiles=20000000

Because then we will have interim-files saved every 20000000 iteration and interim We4 residues every 20000000 interation, so we can compare the residues and will have intermediary files to go back to if the residues don't match.

I have not yet decided if I will do the LL on M595999993 because it will demand such a lot of resources for such a long time but I presently consider it. If not I will release the exponent. I am worried about the error rate.

[QUOTE=aketilander;291741]Well, for me its no problem if anyone would like to try to P-1 M595999993 to an even higher level. It would be difficult though to select the boundaries in the most reasonable way in order not to redo the same work again. I think though that the P-1 I already did is more or less to the level which is considered as reasonable. The assignment gave a credit of 403.6681 Ghz-Days. I had to "little" memory (24 GB) for Brent-Suyama to kick in. The largest exponent I have done with B-S is M397626811 (E=6).

M595999993 is the largest exponent prime95 can handle at the moment. I did the P-1 in order to test the capabilities of the program. Sometimes weaknesses in programs appears when you use them close to their limits.

So anyone can feel free to do more P-1s on M595999993 or to trial factor it beyond ^80 or even try to do a LL (double-check). Please post here if you would like to do more work on M595999993 so that we don't do the same work.

If someone wants to do a LL double-check please use in "prime.txt":

ResultsFileIterations=20000000
InterimFiles=20000000

Because then we will have interim-files saved every 20000000 iteration and interim We4 residues every 20000000 interation, so we can compare the residues and will have intermediary files to go back to if the residues don't match.

I have not yet decided if I will do the LL on M595999993 because it will demand such a lot of resources for such a long time but I presently consider it. If not I will release the exponent. I am worried about the error rate.[/QUOTE]

I'd like to try the P-1, if you don't mind. If you decide to unreserve it from LL, let me know so I can grab it for P-1 from PrimeNet. PrimeNet is down for maintenance... it was TFd to 80, correct?

Edit: OK, I need an opinion. If I TF to 82 first, Prime95 gives:
[CODE]Optimal P-1 factoring of M595999993 using up to 117950MB of memory.
Assuming no factors below 2^82 and 2 primality tests saved if a factor is found.
Optimal bounds are B1=4990000, B2=130987500
Chance of finding a factor is an estimated 4.38%
Using Core2 type-3 FFT length 32M, Pass1=2K, Pass2=16K, 4 threads
[/CODE]

If I leave it at 80:
[CODE]Optimal P-1 factoring of M595999993 using up to 117950MB of memory.
Assuming no factors below 2^80 and 2 primality tests saved if a factor is found.
Optimal bounds are B1=5530000, B2=167282500
Chance of finding a factor is an estimated 5.5%
Using Core2 type-3 FFT length 32M, Pass1=2K, Pass2=16K, 4 threads
[/CODE]

At this point, is it better to go with higher TF, lower P-1 probablity or the other way around?

[QUOTE=flashjh;291748]I'd like to try the P-1, if you don't mind.[/QUOTE]You can, of course, do whatever you want, but I suggest it would be better if you tried P-1 on another exponent, since Åke already did a pretty good P-1 on 595999993. [url=http://mersenne-aries.sili.net/M595999973]M595999973[/url] already has a small factor; the smallest unfactored exponent is [url=http://mersenne-aries.sili.net/M595999939]M595,999,939[/url].

[QUOTE=flashjh;291748]At this point, is it better to go with higher TF, lower P-1 probablity or the other way around?[/QUOTE]Take TF up to at least 82 (about a week on a GPU) and do the smaller P-1.

[QUOTE=James Heinrich;291754]You can, of course, do whatever you want, but I suggest it would be better if you tried P-1 on another exponent, since Åke already did a pretty good P-1 on 595999993. [URL="http://mersenne-aries.sili.net/M595999973"]M595999973[/URL] already has a small factor; the smallest unfactored exponent is [URL="http://mersenne-aries.sili.net/M595999939"]M595,999,939[/URL].

Take TF up to at least 82 (about a week on a GPU) and do the smaller P-1.[/QUOTE]

:smile:

Ok, looking for some help here.

I have a machine that does nothing but P-1. I had UDIMM memory in it and the memory kept going bad, I was getting restarts, etc.

I replaced the UDIMM memory with RDIMM ECC memory on the KGPE-D16 QVL. The system has been very stable, but I noticed it stopped finding S-2 factors.

It had been so long since it found S-2 factor that I gave it [URL="http://mersenne-aries.sili.net/exponent.php?exponentdetails=54699223"]M54699223[/URL] to work on since Dubslow found one:

[QUOTE=Dubslow;291362]Brent-Suyama 0_o

[URL="http://mersenne-aries.sili.net/exponent.php?factordetails=3546977485247966555997217"][COLOR=#0066cc]http://mersenne-aries.sili.net/exponent.php?factordetails=3546977485247966555997217[/COLOR][/URL]

[COLOR=#0066cc]:mellow:[/COLOR]

k = 2^4 × 3 × 1367 × 1427 × [U][B]346 268 953[/B][/U] (81.55 bits)

B2 = 8,906,250;
factor = 346,268,953

factor/B2 = 38.9

For every other expo on this comp, E=12, but P95 doesn't report E when a factor is found.[/QUOTE]

So when I ran it, the system didn't find the factor:

[CODE]
[Mon Mar 12 14:48:12 2012]
UID: flashjh/P1Main, M54699223 completed P-1, B1=475000, B2=9025000, E=12, We4: 878AB6EE
[/CODE]

My B2 was a little higher than Dubslow's, but that shouldn't matter, correct? Anyone have any ideas why the system isn't fining S-2 factors?

I would try one that doesn't require Brent-Suyama. The extension is kinda funny when it comes to the math, and it doesn't necessarily check every potential k under a given bound, otherwise we wouldn't bother with E and just call it a higher B2. I wouldn't be surprised at all if the different bounds did in fact play a part in what E=12 can find. I would run a S2 on a factor which can in fact be found without E (e.g. [URL="http://mersenne-aries.sili.net/exponent.php?exponentdetails=49197853"]this one[/URL] or most any other on the GPU272 top factors report), and if that factor is found, then rerun this E=12 test with exactly the same bounds as I had (reported on Mersenne-aries).