Bug in iteration count in Prime95?

JuanTutors · 2021-10-29, 18:51

I am doing a PRP test on M332290099 (again after restarting after I gave up on it after a ton of Gerbicz errors and then went back to it but the save files were bad so the test restarted).

I noticed that it said "Iteration: 6645800/332290098" (SEE ATTACHED IMAGE.)

I thought "weird, I never noticed in all this time that second number is 1 less than the exponent". But then I went home and checked on one of my home computers and the second number is definitely the exponent and not 1 less than the exponent.

Did I run into a bug?

kriesel · 2021-10-29, 20:23

Quote:

Originally Posted by JuanTutors

Did I run into a bug?

No.
LL does p-2 iterations. https://en.wikipedia.org/wiki/Lucas%...primality_test
PRP does p-1 iterations. https://en.wikipedia.org/wiki/Fermat_primality_test

JuanTutors · 2021-10-29, 22:53

Quote:

Originally Posted by kriesel

No.
LL does p-2 iterations. https://en.wikipedia.org/wiki/Lucas%...primality_test
PRP does p-1 iterations. https://en.wikipedia.org/wiki/Fermat_primality_test

Yes, BUT here are my iterations at home for M332316293 and M332292529 (See image):

"Iteration: 203663120/332292529"
"Iteration: 168611800/332316293"

I see the same thing on my desktop. The number of iterations it states is the exponent.

LaurV · 2021-10-30, 04:27

You are running [U][B]two[/B][/U] workers. Each worker has its own exponent. Hint: read your output lines careful.
Probably (accidentally or intentionally) you selected from the menus "windows/show all workers in the same window".
Scratch that. I misunderstood your question. Going for the morning coffee...

Are you running same version of p95, and same test type?

Prime95 · 2021-10-30, 06:29

Quote:

Originally Posted by kriesel

LL does p-2 iterations. https://en.wikipedia.org/wiki/Lucas%...primality_test

Yes but prime95 has a bug where it starts numbering LL iterations at 3.

JuanTutors · 2021-10-30, 15:10

Quote:

Originally Posted by LaurV

Are you running same version of p95, and same test type?

All running PRP. At home, I confirmed that my laptop running 2 instances that I took a picture of above is running 30.3 b6. I also confirmed that my desktop upstairs (not pictured) is running 30.5 b2 for some reason. The one at work that as one less iteration that I showed above is running 30.3 b6 according to mersenne.org, which I assume is accurate. I never checked a 4th computer.

Quote:

Originally Posted by Prime95

Yes but prime95 has a bug where it starts numbering LL iterations at 3.

I checked to see if I am running LL tests accidentally, but these are all PRP tests. I am sure you can check my username through mersenne.org to confirm.

Prime95 · 2021-10-30, 17:32

Looking at the code (which has not changed among all the versions you are using), the only way I see for the iteration counter to be one less than the exponent is to set

PRPStraightForward=1

in prime.txt. This disables Gerbicz error checking and proofs.

JuanTutors · 2021-10-30, 19:13

Quote:

Originally Posted by Prime95

Looking at the code (which has not changed among all the versions you are using), the only way I see for the iteration counter to be one less than the exponent is to set

PRPStraightForward=1

in prime.txt. This disables Gerbicz error checking and proofs.

I will look to see if that is set when I get to that computer on Monday. However, I did not set that option manually. I didn't know that option existed, and the computer in question is the one that has been having problems, so I would not have set it up to avoid Gerbicz error checking.

Prime95 · 2021-10-30, 19:53

You may need to send me prime.txt, local.txt, worktodo.txt, and a savefile.

JuanTutors · 2021-10-30, 20:08

Quote:

Originally Posted by Prime95

You may need to send me prime.txt, local.txt, worktodo.txt, and a savefile.

Will do when I get to work on Monday. Please let me know how to do that. This is a restarted test as well because the first four save files were detected as bad.

Prime95 · 2021-10-30, 21:28

Quote:

Originally Posted by JuanTutors

Please let me know how to do that.

Dropbox, email, whatever works for you. The files will be in the same folder as prime95.exe.

2021-10-29, 18:51	#1
JuanTutors "Juan Tutors" Mar 2004 1000111011₂ Posts	Bug in iteration count in Prime95? I am doing a PRP test on M332290099 (again after restarting after I gave up on it after a ton of Gerbicz errors and then went back to it but the save files were bad so the test restarted). I noticed that it said "Iteration: 6645800/332290098" (SEE ATTACHED IMAGE.) I thought "weird, I never noticed in all this time that second number is 1 less than the exponent". But then I went home and checked on one of my home computers and the second number is definitely the exponent and not 1 less than the exponent. Did I run into a bug? Attached Thumbnails Last fiddled with by JuanTutors on 2021-10-29 at 18:56

2021-10-30, 04:27	#4
LaurV Romulan Interpreter "name field" Jun 2011 Thailand 10100000110011₂ Posts	You are running [U][B]two[/B][/U] workers. Each worker has its own exponent. Hint: read your output lines careful. Probably (accidentally or intentionally) you selected from the menus "windows/show all workers in the same window". Scratch that. I misunderstood your question. Going for the morning coffee... Are you running same version of p95, and same test type? Last fiddled with by LaurV on 2021-10-30 at 04:31

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2021-10-30, 17:32	#7
Prime95 P90 years forever! Aug 2002 Yeehaw, FL 17×487 Posts	Looking at the code (which has not changed among all the versions you are using), the only way I see for the iteration counter to be one less than the exponent is to set PRPStraightForward=1 in prime.txt. This disables Gerbicz error checking and proofs.

2021-10-30, 19:53	#9
Prime95 P90 years forever! Aug 2002 Yeehaw, FL 20127₈ Posts	You may need to send me prime.txt, local.txt, worktodo.txt, and a savefile.