Prime95 30.8 (big P-1 changes, see post #551)

[lisanderke]

Apologies for the double post, but some new things to report;


- 8420261 successfully reported to Primenet using 30.8 (B2 = 857xB1? Primality tests saved is set to 10 on these exponents, not sure if that is sane at all but you did mention that B2 should be very high.)
- Indicated completion dates seem to be wildly off, this exponent took only 15 minutes to complete P-1 stage1 & 2 but indicated completion time for the next similar exponent is 5 hrs and 30 minutes.

[lycorn]

Originally Posted by Prime95

[*]Use much more aggressive B2 bounds. While the optimal B2 calculations may not be perfect I recommend using them anyway.

Shall we leave the B1/B2 values in the worktodo file at B2 = 100*B1 so the program will choose the optimum figures for Stage 2, like in previous versions?

[kruoli]

It crashes for me with

Error code: 0xc0000005
Error offset: 0x0000000002084266

when entering stage 2 with

Pminus1=N/A,1,2,21356873,-1,1000000,32400000,75

on Zen 2. Roundoff error check is enabled.

[Prime95]

Originally Posted by lisanderke

- 8420261 successfully reported to Primenet using 30.8 (B2 = 857xB1? Primality tests saved is set to 10 on these exponents, not sure if that is sane at all but you did mention that B2 should be very high.)
- Indicated completion dates seem to be wildly off, this exponent took only 15 minutes to complete P-1 stage1 & 2 but indicated completion time for the next similar exponent is 5 hrs and 30 minutes.

This looks fine. Yes, time estimates will be wildly off the mark. Tidying up the incorrect 0.0% stage 2 messages and these time estimates have not been worked on -- part of why I call this an emergency pre-beta release. I felt it was important to get these significant improvements into the 20M groups hands ASAP.

Originally Posted by lycorn

Shall we leave the B1/B2 values in the worktodo file at B2 = 100*B1 so the program will choose the optimum figures for Stage 2, like in previous versions?

Good plan.

[Zhangrc]

Originally Posted by Prime95

Sadly, wavefront P-1 will not benefit much. There are only 200 or so temporaries available if given 16GB RAM.

However, for people who have sufficient RAM, like Ben Delo, I think it's better to use 30.8.
I will continue to use 30.7b8, considering that I only give 9GB of RAM to Prime95.

[firejuggler]

If this is of any help, here are the factor I found 6.2-6.3M with their B1/B2 value

[Luminescence]

Originally Posted by kruoli

It crashes for me with

Error code: 0xc0000005
Error offset: 0x0000000002084266

when entering stage 2 with

Pminus1=N/A,1,2,21356873,-1,1000000,32400000,75

on Zen 2. Roundoff error check is enabled.

Where can I find error logs or where can I turn them on? I ran

Pminus1=1,2,27237523,-1,3000000,300000000,75

and stage 1 was normal (FFT 1440K), stage 2 init finished with a roundoff warning (FFT 1680K) and ran stage 1 from a late savefile again (with FFT 1536k).

P95 then just blew up when it hit stage 2 init again. Using a Zen 3 5900X

[petrw1]

See photos of:
Prime95 Window
CPU SPecs
2 pages of Crash error page.

[Zhangrc]

BUG report -- P-1 missed a factor!
Win10, V30.8b1, on AMD R7 4800H, 4 cores, 1 worker, 16G(8Gx2) DDR4 RAM, 11G of which allocated to Prime95.

[Nov 26 11:49] P-1 on M111298777 with B1=50000, B2=5000000
[Nov 26 11:49] Using FMA3 FFT length 6M, Pass1=1536, Pass2=4K, clm=1, 4 threads
[Nov 26 11:49] Setting affinity to run helper thread 1 on CPU core #3
[Nov 26 11:49] Setting affinity to run helper thread 2 on CPU core #4
[Nov 26 11:49] Setting affinity to run helper thread 3 on CPU core #5
[Nov 26 12:00] M111298777 stage 1 complete. 144422 transforms. Total time: 675.438 sec.
[Nov 26 12:01] Conversion of stage 1 result complete. 5 transforms, 1 modular inverse. Time: 40.386 sec.
[Nov 26 12:01] Switching to FMA3 FFT length 6720K, Pass1=896, Pass2=7680, clm=2, 4 threads
[Nov 26 12:01] Setting affinity to run helper thread 2 on CPU core #4
[Nov 26 12:01] Setting affinity to run helper thread 1 on CPU core #3
[Nov 26 12:01] Setting affinity to run helper thread 3 on CPU core #5
[Nov 26 12:01] Using 11104MB of memory.  D: 330, 40x161 polynomial multiplication.
[Nov 26 12:01] Setting affinity to run polymult helper thread on CPU core #3
[Nov 26 12:01] Setting affinity to run polymult helper thread on CPU core #4
[Nov 26 12:01] Setting affinity to run polymult helper thread on CPU core #5
[Nov 26 12:25] M111298777 stage 2 complete. 154271 transforms. Total time: 1414.600 sec.
[Nov 26 12:25] Round off: 0
[Nov 26 12:25] Stage 2 GCD complete. Time: 24.876 sec.
[Nov 26 12:25] M111298777 completed P-1, B1=50000, B2=5016990, Wi4: 3F048071

Results.json.txt:

[Fri Nov 26 12:25:50 2021]
{"status":"NF", "exponent":111298777, "worktype":"P-1", "b1":50000, "b2":5016990, "fft-length":6881280, "security-code":"3F048071", "program":{"name":"Prime95", "version":"30.8", "build":1, "port":4}, "timestamp":"2021-11-26 04:25:50"}

However, M111298777 has a P-1 smooth factor: 135398831970267435540791 (k = 5 × 23 × 37 × 313 × 1069 × 427241).
This is a TF factor found by me long ago. Theoretically, it could be found by the P-1 above.

[petrw1]

Originally Posted by Zhangrc

BUG report -- P-1 missed a factor!
Win10, V30.8b1, on AMD R7 4800H, 4 cores, 1 worker, 16G(8Gx2) DDR4 RAM, 11G of which allocated to Prime95.

[Nov 26 11:49] P-1 on M111298777 with B1=50000, B2=5000000

However, M111298777 has a P-1 smooth factor: 135398831970267435540791 (k = 5 × 23 × 37 × 313 × 1069 × 427241).
This is a TF factor found by me long ago. Theoretically, it could be found by the P-1 above.

Just as a double check I ran it with 30.7 and 50,000/500,000

[Comm thread Nov 25 23:36] Sending result to server: UID: petrw1/Magic_8_Ball, M111298777 has a factor: 135398831970267435540791 (P-1, B1=50000, B2=500000)

[Prime95]

Thanks everyone! You've given me several bugs to hunt down. Please stop using 30.8 for now.

Edit: 30.8 removed from the server.