20200930, 17:14  #1 
Feb 2020
Germany
25_{16} Posts 
Noob question about primality checking
Hi everyone,
I have a noob question about the pari scripts that are used to test primes that can not be factored / certified by primo that easily. I would like to do these tests in addition to the N1/N+1 tests that pfgw does with my candidates. Currently I am a bit obsessed with general repunit primes and I came across the additional information (http://xenon.stanford.edu/~tjw/pp/index.html) on C. Caldwell's prime page of these numbers. There CHG, KP and BLS scripts where used to check for primality. I already downloaded the 'Coppersmith  HowgraveGraham Primality Prover' as pari script and the 'Coppersmith  HowgraveGraham Primality Prover' script. I have a good understanding of programming/scripts but here I have no clue how to feed my candidates/factors into those scripts. The thread ' If you find a prime...' (https://www.mersenneforum.org/showthread.php?t=19118) unfortunally did not help. Could someone please explain to me how to use them, do the nessesary preperatory work and where the input files come from or point me to a documentation I have missed ? kind regards hunson Last fiddled with by hunson on 20200930 at 17:23 
20200930, 18:21  #2  
Sep 2002
Database er0rr
3·1,327 Posts 
Quote:
For CHG you need "known factors" of n1 and n+1: Quote:
Adjust the script: Code:
\\ PROGRAM INPUT \\  worktodofile="TestSuite\/_09.in"; certificatefile="TestSuite\_09.out"; The proof assumes you have run PFGW with the know factors in a helper file. Just list known factors in a file called something like "helper.txt" and run ./pfgw64 hhelper.txt tc <input_file_with_n_in_it> (or the number). PFGW64 is required to say it is FermatPRP and LucasPRP. Last fiddled with by paulunderwood on 20200930 at 19:08 

20201001, 18:09  #3 
Feb 2020
Germany
37 Posts 
Thank you for the explanation.
I have one further question regarding the ~33 % factorisation of the numbers listed at http://xenon.stanford.edu/~tjw/pp/index.html . Can I assume numbers this big are factored on big clusters / universities to finish in a reasonable amount of time ? If so, I might refrain to persue to search for those numbers since I only have one machine to check. kind regards hunson 
20201001, 18:17  #4  
Sep 2002
Database er0rr
3×1,327 Posts 
Quote:


20201002, 14:19  #5 
Feb 2020
Germany
37 Posts 
Again, thanks for the reply.
I tried to contact T. Wu, but it seems that the email addres no longer works. Ok, lets not get to off topic. I will try to set up the software to do a test. Thanks. 
20201002, 14:52  #6 
Sep 2002
Database er0rr
3981_{10} Posts 
There may be some low hanging fruit in the masses of data in factorDB, for you to practice some ECM/CHG/KP on. Perhaps some one else can give pointers to likely numbers
Last fiddled with by paulunderwood on 20201002 at 14:54 
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