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-   -   Unexpected termination of PM-1 (https://www.mersenneforum.org/showthread.php?t=27331)

Miszka 2021-11-18 18:07

Unexpected termination of PM-1
 
2 Attachment(s)
I'm using Prime95v. 30. 7b4
During implementation:
Pminus1=N/A,1,2,3779,-1,40000000000,2000000000000,68,"7559,2086009,6084191,274476660553,5086072485847,6306850735777,3476227576267836521,2078022893280176212649"
The program aborted after finishing the first stage and calculating B2=999*B1=39960000000000 without any message, writing to the log, or sending the result to the GIMPS server (See Photo1).

I restarted the program forcing the value B2=2000000000000
Pminus1=N/A,1,2,3779,-1,40000000000,2000000000000,"7559,2086009,6084191,274476660553,5086072485847,6306850735777,3476227576267836521,2078022893280176212649"
The program has again terminated unexpectedly (See Photo2).

Perhaps the B2 value used (calculated) is too large and exceeds the allowable limit?
I don't know, because there is no announcement.

Viliam Furik 2021-11-18 18:13

[QUOTE=Miszka;593392]I'm using Prime95v. 30. 7b4
During implementation:
Pminus1=N/A,1,2,3779,-1,40000000000,2000000000000,68,"7559,2086009,6084191,274476660553,5086072485847,6306850735777,3476227576267836521,2078022893280176212649"
The program aborted after finishing the first stage and calculating B2=999*B1=39960000000000 without any message, writing to the log, or sending the result to the GIMPS server (See Photo1).

I restarted the program forcing the value B2=2000000000000
Pminus1=N/A,1,2,3779,-1,40000000000,2000000000000,"7559,2086009,6084191,274476660553,5086072485847,6306850735777,3476227576267836521,2078022893280176212649"
The program has again terminated unexpectedly (See Photo2).

Perhaps the B2 value used (calculated) is too large and exceeds the allowable limit?
I don't know, because there is no announcement.[/QUOTE]

I had similar issues before, with small exponents and huge B1/B2. I don't remember the details exactly, but I think I had problem with B2 being too large. That's probably the reason for you too.

Miszka 2021-11-18 18:24

And what's the biggest value B2 can be?

Viliam Furik 2021-11-18 20:07

[QUOTE=Miszka;593394]And what's the biggest value B2 can be?[/QUOTE]

Not sure... But it's easy to find out. Try which ones work! It's like a guessing game.

kriesel 2021-11-18 20:45

[QUOTE=Viliam Furik;593405]Not sure... [/QUOTE]Or read the source code, perhaps while a guess runs.

Viliam Furik 2021-11-18 21:23

[QUOTE=kriesel;593411]Or read the source code, perhaps while a guess runs.[/QUOTE]

Frankly, that didn't occur to me... :blush::bow:

Prime95 2021-11-18 23:37

[QUOTE=Miszka;593392]I'm using Prime95v. 30. 7b4

Pminus1=N/A,1,2,3779,-1,40000000000,2000000000000,68,[/QUOTE]

Prime95 is the wrong tool for the job. Use GMP-ECM.

tuckerkao 2021-11-19 04:52

[QUOTE=Miszka;593394]And what's the biggest value B2 can be?[/QUOTE]
It depends on the available memories of the user's PC. Many larger factors require the bounds to be up to 2^14 or greater which can be out of reach by many models. ECM has the higher chance to find such the useful factors, but require many curves to be run before able to find 1.

ATH 2021-11-19 06:20

[QUOTE=Miszka;593394]And what's the biggest value B2 can be?[/QUOTE]

With GMP-ECM you can run stage2 in as many stages as you want, going as high as you want. First you run stage1 and save the result:

ecm.exe -v -pm1 -save M3779stage1.txt 4e10 4e10 < M3779.txt

The "M3779.txt" file is just this line:
[CODE](2^3779-1)/7559/2086009/6084191/274476660553/5086072485847/6306850735777/3476227576267836521/2078022893280176212649[/CODE]

Then you can just run stage2 like this:
ecm.exe -v -pm1 -resume M3779stage1.txt 4e10 4e10-1e13 < M3779.txt
ecm.exe -v -pm1 -resume M3779stage1.txt 4e10 1e13-2e13 < M3779.txt
ecm.exe -v -pm1 -resume M3779stage1.txt 4e10 2e13-3e13 < M3779.txt
etc.

You can adjust the interval you want to run each time depending on how much memory you want to use. 1e13 takes 2784 MB. Generally I think running as high an interval as possible each time is faster than running many small intervals, but don't remember if that is always the case. I seem to remember testing than sometimes it was not.

Miszka 2021-11-19 07:33

[QUOTE=Prime95;593418]Prime95 is the wrong tool for the job. Use GMP-ECM.[/QUOTE]

I made several attempts to determine the value of B2 to complete my task.
Only B2=B1=40000000000 was successful.
In this experimental way I found out that for small Mersenne numbers the P-1 method is not a good method.

Prime95 2021-11-19 15:51

[QUOTE=Miszka;593434]I made several attempts to determine the value of B2 to complete my task.
Only B2=B1=40000000000 was successful.
In this experimental way I found out that for small Mersenne numbers the P-1 method is not a good method.[/QUOTE]

Keep the save file. Version 30.8 may be able to complete stage 2.


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