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Old 2016-03-16, 20:23   #1
UberNumberGeek
 
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Default P-1 factoring attempts at smallest-remaining Mersenne numbers with no known factors

Hello, Geniuses,

I recently ran 4-month long P-1 tests on M1277, M1619, M1753, and M2137.

I would like to ask for your opinion on what I should do next, please.

I still have the 244 MB files generated by the tests, am I able to increase the B1 and B2 for these tests and, essentially, pick up where I left off?

If so, should I do that since I already have so much time invested?

Thank you for your time and any explanations provided!
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Old 2016-03-16, 21:11   #2
VictordeHolland
 
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If you want to attempt to factor these low Mersenne numbers, you'll want to run ECM curves with high bounds. ECM with B1=800,000,000 for starters. Prime95 has options to do that. You could also give GMP-ECM a try for the stage 2. Curves wirh higher bounds can find larger factors, but take longer to complete.
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Old 2016-03-16, 21:26   #3
UberNumberGeek
 
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Quote:
Originally Posted by VictordeHolland View Post
If you want to attempt to factor these low Mersenne numbers, you'll want to run ECM curves with high bounds. ECM with B1=800,000,000 for starters. Prime95 has options to do that. You could also give GMP-ECM a try for the stage 2. Curves wirh higher bounds can find larger factors, but take longer to complete.
Thank you for replying, Victor!

I am running ECM curves at B1=800,000,000 and B2=80,000,000,000, but on my PC 1 curve takes 2 hours to run, and according to the ECM chart, there are still over 300,000 curves to be run for these numbers at those bounds.

I was hoping that P-1 factoring would find a nice, "smooth" factor and save time. In the 4 months it took my P-1 factoring to complete, I could have only completed a few thousand curves of ECM, still a small percentage.

And, again, I was hoping that, since I have already spent 4 months on P-1 factoring, that I could up the bounds and pick up where I left off and maybe find a decent-sized factor that was bigger than the 65-digit "limit" those bounds imply.

Thank you again!
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Old 2016-03-16, 21:39   #4
Prime95
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For these small Mersennes it is an absolute must to use prime95 for stage 1 and GMP-ECM for stage 2. There are forum threads that show how to do this.
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Old 2016-03-16, 22:01   #5
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Quote:
Originally Posted by Prime95 View Post
For these small Mersennes it is an absolute must to use prime95 for stage 1 and GMP-ECM for stage 2. There are forum threads that show how to do this.
I am honored that you replied to my thread, thank you.

I am melancholy that I have been doing things the wrong way and have been wasting precious time.

Thank you for letting me know, I am sorry to waste everyone's time. I will try to find how to start using GMP-ECM.

Thank you for everything Prime95 has given and taught me.
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Old 2016-03-16, 22:19   #6
VBCurtis
 
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I am running ECM with large bounds (B1 = 4.5e9 B2 = 2e14) on M1277. I have 3 Xeon cores doing so, making slow progress but thus far too lazy to submit manual curve results to George.

1277 has had by far the most work done, so it is least likely to produce a factor per unit of CPU time invested. I'd personally like the help finishing a t65 on it, but the other three get less attention so there's reason to take shots at those too. I second the suggestion to run curves at B1 no lower than 8e8 on these four.

As for getting GMP-ECM to work with P95, P95 needs GmpEcmHook=1 in the settings file (prime.txt or local.txt, I forget). B2 is set no higher than B1, and the results file saves the residue from stage 1. GMP-ECM is then run with -resume <inputfile, B1 set to 1, and B2 set to whatever you like (or, perhaps, not set and GMP-ECM will pick it for you). Lots more detail if you find the other thread.
Good luck!
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Old 2016-03-16, 22:45   #7
ATH
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I have previously done big P-1 run and 2 big P+1 runs on M1277 using only GMP-ECM for both stage 1 and stage 2:

P-1: B1=1012 B2=2.35*1017

P+1: B1=5*1011 B2=5.4*1016

P+1: B1=5*1011 B2=7.8*1016

I have the save files if anyone want to take them higher.
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Old 2016-10-18, 23:20   #8
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I would be interested in P-1 or P+1 save files for small exponents.

For exponents in the low single-digit-thousands, I think these files should be only a few hundred bytes long. The intermediate files (.bu or .bu2) might be very large (hundreds of MB), but the non-bu final savefile should be really tiny for those very small exponents, assuming the P-1 or P+1 test actually ran to completion.

Amazon EC2 cloud has some instances with large amounts of memory, all the way up to x1.16xlarge with 976 GiB and 32 cores, and x1.32xlarge with 1952 GiB and 64 cores. The spot prices are about $0.70/hour and $1.50/hour for these, and there are others with less memory for lower cost. I have no idea how long stage 2 might take with GMP-ECM, but if it's days rather than months then something might be feasible.

When you guys did your tests, were you constrained by available memory or by CPU time, or both?

Sadly, openmp does not seem to work properly with P-1 for GMP-ECM, so only one thread could be used per exponent. If this bug could be fixed then perhaps it might go faster.

Last fiddled with by GP2 on 2016-10-18 at 23:21
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Old 2016-11-16, 19:07   #9
GP2
 
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Quote:
Originally Posted by ATH View Post
I have previously done big P-1 run and 2 big P+1 runs on M1277 using only GMP-ECM for both stage 1 and stage 2:

P-1: B1=1012 B2=2.35*1017

P+1: B1=5*1011 B2=5.4*1016

P+1: B1=5*1011 B2=7.8*1016

I have the save files if anyone want to take them higher.

I obtained these save files and took them to:

Pāˆ’1: B1=1014774826757 (unchanged) B2=4.55e18
P+1: B1=ā€‡510021907147 (unchanged) B2=1.00e18
P+1: B1=ā€‡512993898541 (unchanged) B2=9.15e17

with no result.

Last fiddled with by GP2 on 2016-11-16 at 19:18
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Old 2016-11-16, 22:21   #10
petrw1
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Quote:
Originally Posted by Prime95 View Post
For these small Mersennes it is an absolute must to use prime95 for stage 1 and GMP-ECM for stage 2. There are forum threads that show how to do this.
When you say "...smaller Mersennes..." up to what size?
I'm looking to try to ECM Factor a Prime or 2 for Primes under 20,000.
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Old 2016-12-14, 18:36   #11
petrw1
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Default Interested in furthering P-1 for sub 20,000 Exponents.

I put together this list of sub-20,000 Exponents with the lowest B1/B2 done so far.
Granted even these are VERY large but I am thinking of taking these higher.
I have a decent PC with 16GB of RAM running nothing but GIMPS.

Unless the wiser among you advise this a a big waste of time...
I am also going to run LOTS of ECM as well.
My 2017 goal is to first-factor at least 1 sub-20,000 exponent.

I listed the latest B1/B2 on record and who did that test.
If any any you still have the the save files PM me.

Code:
7127	63	 60,000,000,000 	 4,800,000,000,000 	Mikr
7621	63	 60,000,000,000 	 4,800,000,000,000 	Mikr
8291	62	 60,000,000,000 	 4,800,000,000,000 	Mikr
10399	63	 10,000,000,000 	 100,000,000,000 	bcp19
10463	63	 10,000,000,000 	 500,000,000,000 	bcp19
10771	63	 10,000,000,000 	 500,000,000,000 	bcp19
10831	63	 10,000,000,000 	 100,000,000,000 	bcp19
11027	63	 10,000,000,000 	 100,000,000,000 	bcp19
11159	63	 10,000,000,000 	 100,000,000,000 	bcp19
11251	63	 10,000,000,000 	 100,000,000,000 	bcp19
11351	63	 10,000,000,000 	 100,000,000,000 	bcp19
11423	63	 10,000,000,000 	 100,000,000,000 	bcp19
11467	63	 10,000,000,000 	 100,000,000,000 	bcp19
11483	63	 10,000,000,000 	 100,000,000,000 	bcp19
11489	63	 10,000,000,000 	 100,000,000,000 	bcp19
11657	63	 10,000,000,000 	 100,000,000,000 	bcp19
11821	63	 10,000,000,000 	 100,000,000,000 	bcp19
11839	63	 10,000,000,000 	 100,000,000,000 	bcp19
12149	63	 10,000,000,000 	 100,000,000,000 	bcp19
12161	63	 10,000,000,000 	 100,000,000,000 	bcp19
12269	63	 10,000,000,000 	 100,000,000,000 	bcp19
12281	63	 10,000,000,000 	 100,000,000,000 	bcp19
12377	63	 10,000,000,000 	 100,000,000,000 	bcp19
12517	63	 10,000,000,000 	 100,000,000,000 	bcp19
12637	63	 10,000,000,000 	 100,000,000,000 	bcp19
13007	63	 10,000,000,000 	 500,000,000,000 	bcp19
13217	63	 10,000,000,000 	 100,000,000,000 	bcp19
13219	63	 10,000,000,000 	 100,000,000,000 	bcp19
13327	63	 10,000,000,000 	 100,000,000,000 	bcp19
13523	63	 10,000,000,000 	 100,000,000,000 	bcp19
13597	63	 10,000,000,000 	 100,000,000,000 	bcp19
13691	63	 10,000,000,000 	 100,000,000,000 	bcp19
14153	63	 10,000,000,000 	 100,000,000,000 	bcp19
14173	63	 10,000,000,000 	 100,000,000,000 	bcp19
14243	63	 10,000,000,000 	 100,000,000,000 	bcp19
14447	63	 10,000,000,000 	 100,000,000,000 	bcp19
14489	63	 10,000,000,000 	 100,000,000,000 	bcp19
14557	63	 10,000,000,000 	 100,000,000,000 	bcp19
14723	63	 10,000,000,000 	 100,000,000,000 	bcp19
14867	63	 10,000,000,000 	 100,000,000,000 	bcp19
14951	63	 10,000,000,000 	 9,887,122,214,540,710 	bcp19
15017	63	 10,000,000,000 	 100,000,000,000 	bcp19
15077	63	 10,000,000,000 	 100,000,000,000 	bcp19
15259	63	 10,000,000,000 	 100,000,000,000 	bcp19
15349	63	 10,000,000,000 	 100,000,000,000 	bcp19
15451	63	 10,000,000,000 	 100,000,000,000 	bcp19
15497	63	 10,000,000,000 	 100,000,000,000 	bcp19
15559	63	 1,446,830,000 	 43,643,783,079 	Jayder
15643	63	 10,000,000,000 	 100,000,000,000 	c10ck3r
15649	63	 1,446,830,000 	 43,643,783,079 	Jayder
16057	63	 1,446,830,000 	 43,643,783,079 	Jayder
16061	63	 1,851,000,000 	 43,643,783,079 	Jayder
16253	63	 1,446,830,000 	 43,643,783,079 	Jayder
16349	63	 10,000,000,000 	 100,000,000,000 	c10ck3r
16369	63	 10,000,000,000 	 100,000,000,000 	c10ck3r
16381	63	 10,000,000,000 	 100,000,000,000 	c10ck3r
16649	63	 984,343,260 	 49,217,163,000 	Jocelyn Larouche
16673	63	 982,360,150 	 49,118,007,500 	Jocelyn Larouche
16843	63	 20,000,000,000 	 200,000,000,000 	blahpy
17053	63	 10,000,000,000 	 100,000,000,000 	blahpy
17077	63	 949,978,502 	 47,498,925,100 	Jocelyn Larouche
17203	63	 1,935,060,000 	 35,360,118,869 	Jayder
17239	63	 20,000,000,000 	 100,000,000,000 	David Campeau
17359	63	 2,000,000,000 	 130,000,000,000 	David Campeau
17393	63	 1,172,220,000 	 35,360,118,869 	Jayder
17471	63	 2,840,000,000 	 2,840,000,000 	Never Odd Or Even
17761	63	 1,172,220,000 	 35,360,118,869 	Jayder
17827	63	 3,000,000,000 	 3,000,000,000 	Sergiosi
18119	63	 2,000,000,000 	 130,000,000,000 	David Campeau
18149	63	 1,172,220,000 	 35,360,118,869 	Jayder
18341	63	 1,172,220,000 	 35,360,118,869 	Jayder
18397	63	 1,172,220,000 	 35,360,118,869 	Jayder
18413	63	 1,172,220,000 	 35,360,118,869 	Jayder
18439	63	 1,172,220,000 	 35,360,118,869 	Jayder
18457	63	 1,172,220,000 	 35,360,118,869 	Jayder
18539	63	 1,172,220,000 	 35,360,118,869 	Jayder
18553	63	 1,172,220,000 	 35,360,118,869 	Jayder
18583	63	 1,172,220,000 	 35,360,118,869 	Jayder
18587	63	 1,172,220,000 	 35,360,118,869 	Jayder
19013	63	 24,250,000,000 	 50,000,000,000 	Sergiosi
19157	63	 1,172,220,000 	 35,360,118,869 	Jayder
19219	63	 1,172,220,000 	 35,360,118,869 	Jayder
19373	63	 1,172,220,000 	 35,360,118,869 	Jayder
19423	63	 1,172,220,000 	 35,360,118,869 	Jayder
19433	63	 1,172,220,000 	 35,360,118,869 	Jayder
19483	63	 1,172,220,000 	 35,360,118,869 	Jayder
19501	63	 1,172,220,000 	 35,360,118,869 	Jayder
19507	63	 10,000,000,000 	 100,000,000,000 	bcp19
19531	63	 10,000,000,000 	 100,000,000,000 	bcp19
19583	63	 10,000,000,000 	 100,000,000,000 	bcp19
19709	63	 10,000,000,000 	 100,000,000,000 	bcp19
19753	63	 10,000,000,000 	 100,000,000,000 	bcp19
19813	63	 10,000,000,000 	 100,000,000,000 	bcp19
19853	63	 10,000,000,000 	 100,000,000,000 	bcp19
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