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 2021-04-24, 22:05 #221 James Heinrich     "James Heinrich" May 2004 ex-Northern Ontario 2·3·569 Posts duplicate post Last fiddled with by James Heinrich on 2021-04-24 at 22:06
2021-04-24, 23:29   #222
R. Gerbicz

"Robert Gerbicz"
Oct 2005
Hungary

148610 Posts

Quote:
 Originally Posted by Prime95 Prime95 version 30.6 build 2 is available. I consider the new features to be lightly tested. No need to upgrade unless you are doing ECM or care to try out the new P+1 factoring work.
Have you included p as a factor in the p+1 (!!) method? Looks like not...
If really not then you will find no p-1 factors where p>B1 (unless with some luck), and all other factors except at most one are smaller than B1, the largest one is <=B2 as usual.
My small example:

M86743 has a factor q=5867520663913, here q-1=2^3*3*19*86743*148339

With the P+1 method, B1=50000,B2=2000000, nthrun=1, so with:
Pplus1=N/A,1,2,86743,-1,50000,2000000,1,40

Code:
[Work thread Apr 25 00:55] P+1 on M86743 with B1=50000, B2=2000000
[Work thread Apr 25 00:55] Chance of finding a factor assuming no ECM has been done is an estimated 7.78%
[Work thread Apr 25 00:55] Using FMA3 FFT length 4K
[Work thread Apr 25 00:55] M86743 stage 1 is 8.92% complete. Time: 0.103 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 18.25% complete. Time: 0.105 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 27.45% complete. Time: 0.103 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 36.68% complete. Time: 0.103 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 45.98% complete. Time: 0.102 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 55.37% complete. Time: 0.103 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 64.64% complete. Time: 0.102 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 73.64% complete. Time: 0.102 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 83.02% complete. Time: 0.102 sec.
[Work thread Apr 25 00:55] M86743 stage 1 is 92.29% complete. Time: 0.103 sec.
[Work thread Apr 25 00:55] M86743 stage 1 complete. 217103 transforms. Time: 1.115 sec.
[Work thread Apr 25 00:55] Stage 1 GCD complete. Time: 0.003 sec.
[Work thread Apr 25 00:55] D: 840, relative primes: 1744, stage 2 primes: 143800, pair%=95.24
[Work thread Apr 25 00:55] Using 57MB of memory.
[Work thread Apr 25 00:55] Stage 2 init complete. 5119 transforms. Time: 0.095 sec.
[Work thread Apr 25 00:55] M86743 stage 2 is 12.63% complete. Time: 0.111 sec.
[Work thread Apr 25 00:55] M86743 stage 2 is 25.68% complete. Time: 0.111 sec.
[Work thread Apr 25 00:55] M86743 stage 2 is 38.86% complete. Time: 0.111 sec.
[Work thread Apr 25 00:55] M86743 stage 2 is 52.03% complete. Time: 0.111 sec.
[Work thread Apr 25 00:55] M86743 stage 2 is 65.02% complete. Time: 0.111 sec.
[Work thread Apr 25 00:55] M86743 stage 2 is 77.73% complete. Time: 0.112 sec.
[Work thread Apr 25 00:55] M86743 stage 2 is 90.49% complete. Time: 0.111 sec.
[Work thread Apr 25 00:55] M86743 stage 2 complete. 154981 transforms. Time: 0.862 sec.
[Work thread Apr 25 00:55] Stage 2 GCD complete. Time: 0.003 sec.
[Work thread Apr 25 00:55] M86743 completed P+1, B1=50000, B2=2000000, Wi8: 024544B3
But with B1=100000,B2=2000000 we can get:
Pplus1=N/A,1,2,86743,-1,100000,2000000,1,40
Code:
[Work thread Apr 25 00:52] P+1 on M86743 with B1=100000, B2=2000000
[Work thread Apr 25 00:52] Chance of finding a factor assuming no ECM has been done is an estimated 8.51%
[Work thread Apr 25 00:52] Using FMA3 FFT length 4K
[Work thread Apr 25 00:52] M86743 stage 1 is 4.33% complete. Time: 0.104 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 9.00% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 13.64% complete. Time: 0.104 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 18.23% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 22.86% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 27.53% complete. Time: 0.105 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 32.23% complete. Time: 0.104 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 36.73% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 41.38% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 46.04% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 50.62% complete. Time: 0.106 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 55.24% complete. Time: 0.104 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 59.66% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 64.43% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 69.11% complete. Time: 0.104 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 73.69% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 78.30% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 82.81% complete. Time: 0.104 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 87.54% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 92.17% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 is 96.58% complete. Time: 0.103 sec.
[Work thread Apr 25 00:52] M86743 stage 1 complete. 435081 transforms. Time: 2.253 sec.
[Work thread Apr 25 00:52] Stage 1 GCD complete. Time: 0.003 sec.
[Work thread Apr 25 00:52] D: 840, relative primes: 1793, stage 2 primes: 139341, pair%=93.26
[Work thread Apr 25 00:52] Using 59MB of memory.
[Work thread Apr 25 00:52] Stage 2 init complete. 5261 transforms. Time: 0.081 sec.
[Work thread Apr 25 00:52] M86743 stage 2 is 12.65% complete. Time: 0.112 sec.
[Work thread Apr 25 00:52] M86743 stage 2 is 25.76% complete. Time: 0.113 sec.
[Work thread Apr 25 00:52] M86743 stage 2 is 39.18% complete. Time: 0.112 sec.
[Work thread Apr 25 00:52] M86743 stage 2 is 52.88% complete. Time: 0.112 sec.
[Work thread Apr 25 00:52] M86743 stage 2 is 65.95% complete. Time: 0.112 sec.
[Work thread Apr 25 00:52] M86743 stage 2 is 78.77% complete. Time: 0.115 sec.
[Work thread Apr 25 00:52] M86743 stage 2 is 91.69% complete. Time: 0.113 sec.
[Work thread Apr 25 00:52] M86743 stage 2 complete. 153070 transforms. Time: 0.863 sec.
[Work thread Apr 25 00:52] Stage 2 GCD complete. Time: 0.003 sec.
[Work thread Apr 25 00:52] P+1 found a factor in stage #2, B1=100000, B2=2000000.
[Work thread Apr 25 00:52] M86743 has a factor: 5867520663913 (P+1, B1=100000, B2=2000000)
[Work thread Apr 25 00:52] No work to do at the present time.  Waiting.
Actually it will discover q only when B1>=p=86743, since for this q the p factor is the 2nd largest factor.

 2021-04-25, 10:55 #223 henryzz Just call me Henry     "David" Sep 2007 Cambridge (GMT/BST) 133718 Posts Is there any logic behind trying to identify which starting values actually do P+1? For example, if we multiply the original composite by a small prime that will be found with very small P+1 bounds or known P+1 factors but won't be found with P-1 then we will know that it is actually doing P+1. The downside of this is that we will have to run P+1 on this larger composite which may mess up the efficiency of the arithmetic for Mersenne numbers. This could be better than running 2 or 3 times though.
2021-04-25, 13:04   #224
ATH
Einyen

Dec 2003
Denmark

7×11×41 Posts

Quote:
 Originally Posted by henryzz Is there any logic behind trying to identify which starting values actually do P+1? For example, if we multiply the original composite by a small prime that will be found with very small P+1 bounds or known P+1 factors but won't be found with P-1 then we will know that it is actually doing P+1. The downside of this is that we will have to run P+1 on this larger composite which may mess up the efficiency of the arithmetic for Mersenne numbers. This could be better than running 2 or 3 times though.
The bounds depends on the smoothness of "the unknown factor we are trying to find +1" not on the original composite, and the same with the seeds x0. If they work or not depends on the unknown factor:
"However not all seeds will succeed: only half of the seeds 'x0' work for P+1
(namely those where the Jacobi symbol of x0^2-4 and P is -1.) Unfortunately,
since P is usually not known in advance, there is no way to ensure that this
holds.
"

2021-04-25, 15:51   #225
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT/BST)

5,881 Posts

Quote:
 Originally Posted by ATH The bounds depends on the smoothness of "the unknown factor we are trying to find +1" not on the original composite, and the same with the seeds x0. If they work or not depends on the unknown factor: "However not all seeds will succeed: only half of the seeds 'x0' work for P+1 (namely those where the Jacobi symbol of x0^2-4 and P is -1.) Unfortunately, since P is usually not known in advance, there is no way to ensure that this holds."
I forgot it was the factor and not the composite.

 2021-04-25, 22:25 #226 ATH Einyen     Dec 2003 Denmark 315710 Posts Moved the posts regarding missing P-1 / P+1 work to the "<20M unfactored" thread: https://mersenneforum.org/showthread.php?t=22476
2021-04-26, 00:41   #227
storm5510
Random Account

Aug 2009

22×3×163 Posts

Quote:
 Originally Posted by Prime95 Prime95 version 30.6 build 2 is available. I consider the new features to be lightly tested. No need to upgrade unless you are doing ECM or care to try out the new P+1 factoring work...
I like to run ECM's of varying sizes at time. I saw something different in the Stage 2 output after I started running this version. Something called "D-Block" in each output line. Is there a special significance to this?

2021-04-26, 01:43   #228
Prime95
P90 years forever!

Aug 2002
Yeehaw, FL

165548 Posts

Quote:
 Originally Posted by storm5510 Something called "D-Block" in each output line. Is there a special significance to this?
No special significance. It is simply a measure of how far along you are in stage 2.

2021-04-27, 03:04   #229
Prime95
P90 years forever!

Aug 2002
Yeehaw, FL

22×7×269 Posts

Quote:
 Originally Posted by gLauss Not sure if it is stupid what I'm doing (it most probably is), but I'm getting stuck for an unreasonable amount of time in the "initializing step" for stage 2 and the CPU is only used a few percent there. Why did it take 6 minutes to initiliaze after calculating stage 1 GCD? Something strange must be going on here. might be a bug...
Fixed in 30.6 build 3

 2021-04-27, 03:20 #230 Prime95 P90 years forever!     Aug 2002 Yeehaw, FL 11101011011002 Posts 30.6 build 3 is ready Prime pairing is ever so slightly better. Lengthy stage 2 init problem on small exponents fixed. Several other minor bug fixes and improvements. Download links: Before downloading, make sure prime.spl is uploaded to the server. There was a bug in spool file format for versions 30.6b1 and 30.6b2. Version 30.6b3 will have no trouble creating and reading spool files that are compatible with version 30.5 and earlier. Windows 64-bit: https://mersenne.org/ftp_root/gimps/p95v306b3.win64.zip Linux 64-bit: https://mersenne.org/ftp_root/gimps/...linux64.tar.gz
 2021-04-27, 04:28 #231 LaurV Romulan Interpreter     Jun 2011 Thailand 25A516 Posts b2 was reasonably working in a win7 computer, 10 cores, 5 workers x2 cores each, therefore I decided to install it in a second computer, 18 cores, 6 workers, x3 cores each. Now, there are two differences, first this is a win10, second, b3 was issued meantime, so I installed b3. I am stuck with "error larger than 0.5, trying to resume from before", in all 6 workers, infinite loop. There is no "before", this is fresh start. When I "stop" all workers, worker 2 and 3 won't stop, but continue to flood the screen. If I exit, it hangs, I see the green icon, but it does nothing and it needs to be stopped from task man. In all this time (screen flooding) it takes about 4% cpu resources. edit: b2 is the same in this computer. Both b2 and b3 will run normal when non-P+1 assignments provided in worktodo. The "flooding" is only if P+1 lines present. Lines are copied from the other computer, where it worked. Last fiddled with by LaurV on 2021-04-27 at 04:59

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