PrimeGrid
Please visit donation page to help the project cover running costs for this month

Toggle Menu

Join PrimeGrid

Returning Participants

Community

Leader Boards

Results

Other

drummers-lowrise

Advanced search

Message boards : 321 Prime Search : Contents of _cmd files

Author Message
Bur
Send message
Joined: 25 Feb 20
Posts: 6
ID: 1241833
Credit: 259,568
RAC: 8,979
PPS LLR Bronze: Earned 10,000 credits (49,181)SGS LLR Bronze: Earned 10,000 credits (27,421)321 Sieve Silver: Earned 100,000 credits (182,966)
Message 138601 - Posted: 3 Mar 2020 | 14:37:02 UTC

To find out which numbers are actually checked on my computer, I had a look into the _cmd files. They contain something like

sr2sieve -p52830560e9 -P52830570e9
These numbers appear a bit large to be the n in the 321 primes.

There is also a large .sieveinput file where the first line read
ABCD 3*2^$a-1 [25000034]
The remainder of the file are many lines of 1 to 3 digit numbers.

Does anyone here know what is the meaning of these two types of files?

Profile JeppeSNProject donor
Avatar
Send message
Joined: 5 Apr 14
Posts: 1050
ID: 306875
Credit: 12,625,030
RAC: 19,678
Found 1 prime in the 2020 Tour de Primes321 LLR Silver: Earned 100,000 credits (360,928)Cullen LLR Bronze: Earned 10,000 credits (98,851)ESP LLR Silver: Earned 100,000 credits (139,922)Generalized Cullen/Woodall LLR Bronze: Earned 10,000 credits (35,236)PPS LLR Ruby: Earned 2,000,000 credits (3,325,400)PSP LLR Silver: Earned 100,000 credits (212,242)SoB LLR Silver: Earned 100,000 credits (237,390)SR5 LLR Silver: Earned 100,000 credits (145,419)SGS LLR Bronze: Earned 10,000 credits (98,826)TRP LLR Bronze: Earned 10,000 credits (71,060)Woodall LLR Silver: Earned 100,000 credits (109,455)321 Sieve Silver: Earned 100,000 credits (175,037)PSA Turquoise: Earned 5,000,000 credits (7,614,290)
Message 138602 - Posted: 3 Mar 2020 | 16:40:47 UTC

Are you aware of the difference between "321 Prime Search (Sieve)" and "321 Prime Search (LLR)"? You are doing the former, the sieve.

That means you are not primality testing any numbers. You are instead checking if the primes in the interval from 52830560e9 to 52830570e9, i.e. near 52*10^15 or 52 quadrillion ("52 peta"), divide any 3*2^n - 1 candidates, I think.

If you want to check a particular number, choose the 321 LLR subproject instead. Tasks take much longer.

/JeppeSN

Ravi Fernando
Project administrator
Project scientist
Send message
Joined: 21 Mar 19
Posts: 54
ID: 1108183
Credit: 5,341,497
RAC: 7,848
321 LLR Silver: Earned 100,000 credits (224,754)ESP LLR Bronze: Earned 10,000 credits (16,570)PPS LLR Amethyst: Earned 1,000,000 credits (1,361,556)PSP LLR Bronze: Earned 10,000 credits (26,371)SoB LLR Silver: Earned 100,000 credits (183,524)SR5 LLR Bronze: Earned 10,000 credits (51,539)SGS LLR Silver: Earned 100,000 credits (135,227)TRP LLR Bronze: Earned 10,000 credits (77,986)321 Sieve Ruby: Earned 2,000,000 credits (3,189,089)AP 26/27 Bronze: Earned 10,000 credits (72,774)
Message 138615 - Posted: 4 Mar 2020 | 1:08:26 UTC

To add to JeppeSN's correct answer: the second file is a sieve file following the "ABCD" format which is used (for example) by the program OpenPFGW. The full documentation for ABCD (as well as two related formats, ABC and ABC2) is included with OpenPFGW; you can find a download link via google.

The short explanation is that it encodes a very long list of numbers of the form 3*2^a-1, where "a" starts at 25,000,034 and then increments by each of the numbers you see below. (There are gaps because we already have factors for some of these numbers.) The 321 sieve program will determine whether any of these numbers are divisible by a prime between 52,830,560,000,000,000 and 52,830,570,000,000,000; if it finds any, it will report the factors back to the server. We will later get to skip the primality test for 3*2^a-1 for that value of a, since we will already know it's composite.

If you are exceptionally observant, you may notice that the ABCD file actually has another line that looks like the first, a little over halfway down. This is for numbers of the form 3*2^a+1 (instead of -1). We are currently sieving both forms for 25,000,000 <= a < 50,000,000.

Bur
Send message
Joined: 25 Feb 20
Posts: 6
ID: 1241833
Credit: 259,568
RAC: 8,979
PPS LLR Bronze: Earned 10,000 credits (49,181)SGS LLR Bronze: Earned 10,000 credits (27,421)321 Sieve Silver: Earned 100,000 credits (182,966)
Message 138652 - Posted: 5 Mar 2020 | 7:27:11 UTC

Thanks for your answers, that helped a lot.

I looked up sieving and found the sieve of Eratosthenes, so I thought 321 Sieve meant the computer was doing that, i.e. crossing out numbers in a given range until only the prime remained.

Profile JeppeSNProject donor
Avatar
Send message
Joined: 5 Apr 14
Posts: 1050
ID: 306875
Credit: 12,625,030
RAC: 19,678
Found 1 prime in the 2020 Tour de Primes321 LLR Silver: Earned 100,000 credits (360,928)Cullen LLR Bronze: Earned 10,000 credits (98,851)ESP LLR Silver: Earned 100,000 credits (139,922)Generalized Cullen/Woodall LLR Bronze: Earned 10,000 credits (35,236)PPS LLR Ruby: Earned 2,000,000 credits (3,325,400)PSP LLR Silver: Earned 100,000 credits (212,242)SoB LLR Silver: Earned 100,000 credits (237,390)SR5 LLR Silver: Earned 100,000 credits (145,419)SGS LLR Bronze: Earned 10,000 credits (98,826)TRP LLR Bronze: Earned 10,000 credits (71,060)Woodall LLR Silver: Earned 100,000 credits (109,455)321 Sieve Silver: Earned 100,000 credits (175,037)PSA Turquoise: Earned 5,000,000 credits (7,614,290)
Message 138662 - Posted: 5 Mar 2020 | 16:45:01 UTC - in response to Message 138652.

I looked up sieving and found the sieve of Eratosthenes, so I thought 321 Sieve meant the computer was doing that, i.e. crossing out numbers in a given range until only the prime remained.


It is crossing out numbers!

The difference is, it is absolutely impossible to continues until only primes remain. It would take forever because the numbers are so big.

Instead we cross out numbers as long as the time/effort it takes to remove one additional number by "crossing out" is still lower or comparable to the time it would take to remove one number by running a full primality test on such a number.

/JeppeSN

Post to thread

Message boards : 321 Prime Search : Contents of _cmd files

[Return to PrimeGrid main page]
DNS Powered by DNSEXIT.COM
Copyright © 2005 - 2020 Rytis Slatkevičius (contact) and PrimeGrid community. Server load 8.16, 5.83, 5.27
Generated 5 Apr 2020 | 20:16:08 UTC