mtsieve

[storm5510]

I use p/sec as a relative speed indicator. On my aging i7 hardware, it will run between 500K and 650K with 7 threads. I have tried 8, but the Windows GUI gets sluggish at times. It is fine at 7. Of course, this throughput depends on how large the series is. There are 36 k's in the series I am running now for CRUS. A smaller series means a little faster. It would be nice if srsieve2 could run faster, but it would need to maintain the stability it has now. This is where the "not broken, don't fix" idea comes from.

[Citrix]

For version 2_4.0 I am getting

twinsieve.exe -k2 -K1000000 -n1000000 -r -b2 -p3 -P10e14
twinsieve v1.3, a program to find factors of k*b^n+1/-1 numbers for fixed b and n and variable k
Sieve started: 3 < p < 1e15 with 499999 terms (2 < k < 1000000, k*2^1000000) (expecting 484095 factors)
  p=0, 0.000 p/sec, no factors found

Am I doing something wrong?
Thanks

[henryzz]

Originally Posted by Citrix

For version 2_4.0 I am getting

twinsieve.exe -k2 -K1000000 -n1000000 -r -b2 -p3 -P10e14
twinsieve v1.3, a program to find factors of k*b^n+1/-1 numbers for fixed b and n and variable k
Sieve started: 3 < p < 1e15 with 499999 terms (2 < k < 1000000, k*2^1000000) (expecting 484095 factors)
  p=0, 0.000 p/sec, no factors found

Am I doing something wrong?
Thanks

You are using an old buggy version. Hopefully an update should solve your issue.

[rogue]

Originally Posted by Citrix

For version 2_4.0 I am getting

twinsieve.exe -k2 -K1000000 -n1000000 -r -b2 -p3 -P10e14
twinsieve v1.3, a program to find factors of k*b^n+1/-1 numbers for fixed b and n and variable k
Sieve started: 3 < p < 1e15 with 499999 terms (2 < k < 1000000, k*2^1000000) (expecting 484095 factors)
  p=0, 0.000 p/sec, no factors found

Am I doing something wrong?
Thanks

This was fixed in twinsieve 1.4. The current version is 1.6.

[rogue]

Originally Posted by Citrix

Here is the simplest pseudocode
1. Get n from command line and classes to be tested (generally +1 or -1 or both); (if n is 2 all primes need to be tested and we do not need to filter as all primes are odd; 2 is the default value)
2. The location where il_PrimeList is initialized with primes we can insert the following lines of code to filter the primes.
(p is current prime)

while (prime<max)
{
if (n>2 && (p%n==+1 || p%n==-1)) {Enter this prime in the array}
else {skip this prime and go to next prime from iterator}
}

3. p%n can be calculated faster for certain n values (ex. n=2^x)- though this might not provide any significant speed up. I will let you decide.

Is "n" the only value to be specified on the command line? I cannot change where the il_PrimeList is populated. I would have to eliminate in TestMegaPrimeChunk(). For the GPU the kernel itself would need to ignore.

[Citrix]

Originally Posted by rogue

This was fixed in twinsieve 1.4. The current version is 1.6.

twinsieve.exe -W16 -k2 -K1000000 -n1000000 -r -b2 -p3 -P10e14 -fA -t1 -r
twinsieve v1.6, a program to find factors of k*b^n+1/-1 numbers for fixed b and n and variable k
Sieve started: 3 < p < 1e15 with 2 terms (3 < k < 999999, k*2^1000000) (expecting 2 factors)
Increasing worksize to 80000 since each chunk is tested in less than a second
Increasing worksize to 10000000 since each chunk is tested in less than a second
Increasing worksize to 50000000 since each chunk is tested in less than a second
Decreasing worksize to 25000000 since each chunk needs more than 5 seconds to test
  p=82453759727, 57.39M p/sec, 1 factors found at 180 sec per factor (last 1 min), 0.0% done. ETC 2023-04-12 17:16

CTRL-C accepted.  Threads will stop after sieving to 158741299859
Sieve interrupted at p=160495427809.
CPU time: 410.95 sec. (21.41 sieving) (4.20 cores)
Fatal Error:  Something is wrong.  Counted terms (0) != expected terms (1)

How does this need to be fixed?

[Citrix]

Originally Posted by rogue

Is "n" the only value to be specified on the command line? I cannot change where the il_PrimeList is populated. I would have to eliminate in TestMegaPrimeChunk(). For the GPU the kernel itself would need to ignore.

The value of N and possible classes need to be specified in the command line. If possible can we allow multiple arbitrary number of classes ex. -f{N,a,b,c,d...}. So we allow p%N=a or b or c or d

You can eliminate in TestMegaPrimeChunk() or wherever you think it would be appropriate.

[rogue]

Originally Posted by Citrix

twinsieve.exe -W16 -k2 -K1000000 -n1000000 -r -b2 -p3 -P10e14 -fA -t1 -r
twinsieve v1.6, a program to find factors of k*b^n+1/-1 numbers for fixed b and n and variable k
Sieve started: 3 < p < 1e15 with 2 terms (3 < k < 999999, k*2^1000000) (expecting 2 factors)
Increasing worksize to 80000 since each chunk is tested in less than a second
Increasing worksize to 10000000 since each chunk is tested in less than a second
Increasing worksize to 50000000 since each chunk is tested in less than a second
Decreasing worksize to 25000000 since each chunk needs more than 5 seconds to test
  p=82453759727, 57.39M p/sec, 1 factors found at 180 sec per factor (last 1 min), 0.0% done. ETC 2023-04-12 17:16

CTRL-C accepted.  Threads will stop after sieving to 158741299859
Sieve interrupted at p=160495427809.
CPU time: 410.95 sec. (21.41 sieving) (4.20 cores)
Fatal Error:  Something is wrong.  Counted terms (0) != expected terms (1)

How does this need to be fixed?

For base 2, even k are already removed, so you don't need -r. I broke this in 1.6. I will fix the code. I think I should remove -r and do that automatically. Thoughts?

[storm5510]

srsieve2 uses values of n and fbncsieve uses values of k.

I don't believe this is a 1-to-1 relationship. So, what is the conversion value for n to k?

[rogue]

Originally Posted by storm5510

srsieve2 uses values of n and fbncsieve uses values of k.

I don't believe this is a 1-to-1 relationship. So, what is the conversion value for n to k?

i don't understand the question.

[storm5510]

Originally Posted by rogue

i don't understand the question.

You don't understand the question. OK. I will make it simpler.

Is k=1e6 the same as n=1e6?