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-   -   Queestion about twinsieve (https://www.mersenneforum.org/showthread.php?t=25443)

hunson 2020-04-09 11:51

Queestion about twinsieve
 
Hey,


I am experimenting a bit with twinsieve.exe.
I tried the following command: twinsieve.exe -k 1 -K 100000000 -b 2 -n 268768 -P 1e14 -W 12
After a while I got this this error message.

[Quote]
p=6057931104593, 53.01M p/sec, 99902590 factors found at 3.15 sec per factor, 6.1% done. ETC 2020-04-10 04:47
Fatal Error: Something is wrong. Counted terms (96257) != expected terms (97304)[/Quote]Can someone please explain to me what I did wrong ? Sieving for -k 1 -K 10000000 -P 1e12 for the same base resulted in no error.


Thanks in advance.

rogue 2020-04-09 12:52

[QUOTE=hunson;542195]I am experimenting a bit with twinsieve.exe.
I tried the following command: twinsieve.exe -k 1 -K 100000000 -b 2 -n 268768 -P 1e14 -W 12
After a while I got this this error message.

Can someone please explain to me what I did wrong ? Sieving for -k 1 -K 10000000 -P 1e12 for the same base resulted in no error.[/QUOTE]

Which version and build date? I will have to take a look.

hunson 2020-04-09 13:41

Hey,


twinsieve is from the mtsieve-framework version 1.9.5, version 1.2.
Sorry can't find the build date.


My machine:
Win10-64bit
AMD Ryzen 3600 (6 cores, 12 threads)

16 GB RAM




Thanks for helping out.

pepi37 2020-04-12 13:55

[QUOTE=hunson;542200]Hey,


twinsieve is from the mtsieve-framework version 1.9.5, version 1.2.
Sorry can't find the build date.


My machine:
Win10-64bit
AMD Ryzen 3600 (6 cores, 12 threads)

16 GB RAM




Thanks for helping out.[/QUOTE]

Old bug you must use start point that is not even

hunson 2020-04-12 15:38

What start point do you mean ? In my case k is not even and works for smaller ranges (1-10.000.000).

rogue 2020-04-12 16:42

[QUOTE=hunson;542200]twinsieve is from the mtsieve-framework version 1.9.5, version 1.2.[/QUOTE]

Try 1.9.6 (assuming I posted it). I fixed a patch when using multiple threads. I haven't had time to try to reproduce this.

Note that for twinsieve, it might be difficult to get maximum utilization from multiple threads due to how fast it goes thru a chunk of work.

rogue 2020-04-12 20:37

I ran a test with 1.9.6 framework. No issues. This means that either the bug has been fixed or I don't have the right conditions for reproducing it.

pepi37 2020-04-12 22:39

[QUOTE=rogue;542465]I ran a test with 1.9.6 framework. No issues. This means that either the bug has been fixed or I don't have the right conditions for reproducing it.[/QUOTE]


I cannot find 1.9.6


e:\MTSIEVE\mtsieve1957\twin>twinsieve -P10000000000 -W6 -k 6 -K 990000000 -n 50000 -b10 -fN -r -o twinb10.txt
twinsieve v1.2, a program to find factors of k*b^n+1/-1 numbers for fixed b and n and variable k
Sieve started: 1 < p < 1e10 with 890999995 terms (6 < k < 990000000, k*10^50000) (expecting 864178223 factors)
Sieve completed at p=10000000019.
Processor time: 104.38 sec. (3.52 sieving) (1.93 cores)
Fatal Error: Something is wrong. Counted terms (2331345) != expected terms (2349970)

rogue 2020-04-12 23:10

I posted 1.9.6 executables on the mtsieve home page. Hopefully that resolves the multi-threading issue.

pepi37 2020-04-12 23:22

[QUOTE=rogue;542478]I posted 1.9.6 executables on the mtsieve home page. Hopefully that resolves the multi-threading issue.[/QUOTE]
Speed is same...as CPU usage.

rogue 2020-04-13 00:16

[QUOTE=pepi37;542479]Speed is same...as CPU usage.[/QUOTE]

I would not expect any speed gains. The best way to gain speed with this sieve is to do one of two things:

1) Run multiple copies then use the factor files to eliminate terms.
2) When running one copy, use -w to increase the number of primes per chunk of work.

In any case I'm hoping that the Fatal Error is gone.


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