mersenneforum.org potential problems in 2022; double-check likely needed
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2022-11-22, 22:27   #23
gd_barnes

"Gary"
May 2007
Overland Park, KS

1179010 Posts

Quote:
 Originally Posted by rebirther R88 250-500k testing range complete, no primes found, 300-350k double check range matching all residues with the first run If you have another important base to double check where a prime is expected but doesn't find anything let me know.
Great. Sounds good. Assumed to be no problems with R88. Thank you for the effort involved!

Future clarification for me and anyone else: The 250-500k testing range only included tests that were sieved out between P=100e12 and 500e12.

A big thanks to Luminescence for doing the sieve to 100e12 and providing factors!

We will be double-checking a good portion of the 2k bases from this year. I need to think about the best way to do that.

 2022-12-23, 20:08 #24 MisterBitcoin     "Nuri, the dragon :P" Jul 2016 Good old Germany 2·443 Posts I lately used srsieve2 a lot, even versions prior v1.5. Now updated to the latest version. Does anyone know which version yoyo is using for yoyo@home; I asked him just in case. Edit: Quick reply: He still uses sr1sieve and sr2sieve. So we should be fine with the deeper sieved files; now it would depend on which software the sieve file was started I guess? Last fiddled with by MisterBitcoin on 2022-12-23 at 20:12
2022-12-23, 22:36   #25
gd_barnes

"Gary"
May 2007
Overland Park, KS

2·32·5·131 Posts

Quote:
 Originally Posted by MisterBitcoin I lately used srsieve2 a lot, even versions prior v1.5. Now updated to the latest version. Does anyone know which version yoyo is using for yoyo@home; I asked him just in case. Edit: Quick reply: He still uses sr1sieve and sr2sieve. So we should be fine with the deeper sieved files; now it would depend on which software the sieve file was started I guess?
Thanks for the info! That's good to know. I am having them re-sieve a few of the files that looked a little strange on the tests remaining for the sieve depth shown. I estimate they will be done in the next couple of weeks. At that point, we will begin a double-check for the lower half of the n-range done on most of the 2k bases. It is mostly the 2k bases where we should have had primes. Not having primes on the 1k bases was not so unusual. If we end up finding missing primes on the 2kers, we will likely have to expand the double-check.

2022-12-26, 16:12   #26
MisterBitcoin

"Nuri, the dragon :P"
Jul 2016
Good old Germany

15668 Posts

Quote:
 Originally Posted by rebirther I hope this does not affect this old bug from srsieve2: Code: 2.2.2 - October 22, 2021 srsieve2, srsieve2cl: version 1.5.3 Modified to not remove terms that are prime as that defeats the purpose of Sierpinski/Riesel searches.
Hmmm. I just realised that I used srsieve2 1.3.1 for my R71 reservation. Up to n=5K I found a bit over 2.2K primes; sounds about fine by me.
Just for fun I will now run a sieve with 1.6.8 and compare both sieve files. If there was a bug, we should notice it in those lower n-ranges I think.

2022-12-26, 20:37   #27
MisterBitcoin

"Nuri, the dragon :P"
Jul 2016
Good old Germany

2·443 Posts

Quote:
 Originally Posted by MisterBitcoin Hmmm. I just realised that I used srsieve2 1.3.1 for my R71 reservation. Up to n=5K I found a bit over 2.2K primes; sounds about fine by me. Just for fun I will now run a sieve with 1.6.8 and compare both sieve files. If there was a bug, we should notice it in those lower n-ranges I think.
Code:
2022-12-20 01:06:48: Sieve started: 3 < p < 5e7 with 22403873 terms (2500 < n < 5000, k*71^n+c) (expecting 21015458 factors)
2022-12-20 01:51:57: Sieve interrupted at p=32456407.  Primes tested 2000152.  Found 21045607 factors.  1358266 terms remaining.  Time 2708.77 seconds

2022-12-26 21:13:02: Sieve started: 3 < p < 32456407 with 22403873 terms (2500 < n < 5000, k*71^n-1) (expecting 20980769 factors)
2022-12-26 21:30:14: Sieve completed at p=32456441.  Primes tested 1999996.  Found 21045607 factors.  1358266 terms remaining.  Time 1030.92 seconds
Everything looks about fine for me

2022-12-30, 01:36   #28
Luminescence

"Florian"
Oct 2021
Germany

2628 Posts

I looked around a bit in the SRBase forum and found this thread:

and this part of a reply:

Quote:
 Using zero-padded FMA3 FFT length 560K, Pass1=448, Pass2=1280, 5 threads, a = 3
As mentioned by George, two functions introduced with Gwnum 30.4 have problems with zero-padded FFTs.

I thought this kind of FFT is used if |c| != 1 but the post on the SRBase forum shows that this is not necessarily the case.

Any opinions on this?

Last fiddled with by Luminescence on 2022-12-30 at 01:37

2022-12-30, 08:09   #29
rebirther

Sep 2011
Germany

1101010101002 Posts

Quote:
 Originally Posted by Luminescence I looked around a bit in the SRBase forum and found this thread: https://srbase.my-firewall.org/sr5/f...ad.php?id=1368 and this part of a reply: As mentioned by George, two functions introduced with Gwnum 30.4 have problems with zero-padded FFTs. I thought this kind of FFT is used if |c| != 1 but the post on the SRBase forum shows that this is not necessarily the case. Any opinions on this?
This was and old thread where we have used llr, in the meantime all llr2 apps were updated to the latest version with gwnum 3.10.

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