mersenneforum.org Sieving for CRUS
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 2015-12-10, 19:53 #1 rebirther     Sep 2011 Germany 65368 Posts Sieving for CRUS Hi Followers, If someone is able to sieve some S/R Bases from 25-100k this would be great. Also 100-200k and 200-400k are welcome. I am out of running these ranges soon in BOINC and I don't want to lose time. Thx in advance! See recent posts in this thread for incomplete sieving reservations. See completed sieve files in the right-hand column of our reservations pages here: http://www.noprimeleftbehind.net/cru...e-reserves.htm http://www.noprimeleftbehind.net/cru...e-reserves.htm Sieving for bases with < ~30 k's remaining is mostly done by Yoyo now. See the status of the sieves here: http://www.rechenkraft.net/yoyo/y_status_sieve.php Last fiddled with by gd_barnes on 2022-11-08 at 07:43 Reason: general info and links
2015-12-10, 21:12   #2
gd_barnes

"Gary"
May 2007
Overland Park, KS

22×2,963 Posts

Quote:
 Originally Posted by rebirther Hi Fellowers, if someone is able to sieve some S/R Bases from 25-100k this would be great. Also 100-200k and 200-400k are welcome. Iam out of running these ranges soon in BOINC and I dont want to loose time. Thx in advance!
My suggestion is to sieve some of the lowest difficulty bases as shown here:
http://www.noprimeleftbehind.net/cru...s-unproven.htm

Most of them will be 100-200k or 200k-400k. There are a lot of bases in that area that can more easily be proven or reduced to 1k or 2k remaining by BOINC.

 2015-12-11, 06:30 #3 LaurV Romulan Interpreter     "name field" Jun 2011 Thailand 282916 Posts Ok, can you tell me one base I could sieve, preferable sr1sieve or sr2sieve job, the limits to go to (about) and the time frame when you need it, and I can allocate some resources to it.
 2015-12-11, 06:34 #4 wombatman I moo ablest echo power!     May 2013 22·463 Posts I'm sieving R347 (with its remaining k of 22) from n=200k to 400k. Not quite to P=1e12 yet, at which point I'll run a PRP test to get a feel for how far I need to sieve.
2015-12-11, 10:08   #5
gd_barnes

"Gary"
May 2007
Overland Park, KS

22·2,963 Posts

Quote:
 Originally Posted by LaurV Ok, can you tell me one base I could sieve, preferable sr1sieve or sr2sieve job, the limits to go to (about) and the time frame when you need it, and I can allocate some resources to it.
Using that list in the link that I posted above, the lowest difficulty bases are S428, S638, and S332. (Wombatman is doing R347.) I'd suggest starting with S428 for n=200k-400k.

2015-12-11, 10:32   #6
LaurV
Romulan Interpreter

"name field"
Jun 2011
Thailand

1028110 Posts

Quote:
 Originally Posted by gd_barnes Using that list in the link that I posted above, the lowest difficulty bases are S428, S638, and S332. (Wombatman is doing R347.) I'd suggest starting with S428 for n=200k-400k.
Ok, sieving S428 for n>200k for a while, to see what's going on. Starting in one hour. Do you need factors file?

2015-12-11, 10:56   #7
gd_barnes

"Gary"
May 2007
Overland Park, KS

1185210 Posts

Quote:
 Originally Posted by LaurV Ok, sieving S428 for n>200k for a while, to see what's going on. Starting in one hour. Do you need factors file?
No

2015-12-11, 11:04   #8
unconnected

May 2009
Moscow, Russia

24·181 Posts

Quote:
 Originally Posted by rebirther Hi Fellowers, if someone is able to sieve some S/R Bases from 25-100k this would be great. Also 100-200k and 200-400k are welcome. Iam out of running these ranges soon in BOINC and I dont want to loose time. Thx in advance!
I have sieve file for S333 100K-250K, but sieve limit is only 1T. Will sieve deeply and send file to Gary.

Last fiddled with by gd_barnes on 2016-01-03 at 10:15 Reason: R333 -> S333

 2015-12-11, 11:54 #9 MyDogBuster     May 2008 Wilmington, DE 1011001001002 Posts Check for doubles People should check when starting a sieve for a base and range to see if the other side (Riesel or Sierp) has the same base with the same range and sieve them together. Saves time and resources. I'll be working on the 25K-100K range doing the doubles first. We don't take sieving reservations so using this thread to give a general area of work would help out a bit.
 2015-12-11, 14:21 #10 LaurV Romulan Interpreter     "name field" Jun 2011 Thailand 3·23·149 Posts R428 seems proven, which saves me of the troubles to learn how use srXsieve to sieve both sides in the same time... Last fiddled with by LaurV on 2015-12-11 at 14:22
 2015-12-13, 04:31 #11 LaurV Romulan Interpreter     "name field" Jun 2011 Thailand 1028110 Posts S428 200k=2, as I just didn't like those numbers being prime for n=1. This is for the category "futile work", but it still can be posted like a puzzle. I found primes for n higher than 1 for all of them, except 2 and 6, but 6 is eliminated by algebraic factorization, it seems that all of them are divisible by 7. So here the primes with higher n: Code: 2*428^1+1 = 857 is prime! (trial divisions) 5*428^1+1 = 2141 is prime! (trial divisions) 9*428^1+1 = 3853 is prime! (trial divisions) 3*428^2+1 = 549553 is prime! (trial divisions) 7*428^2+1 = 1282289 is prime! (trial divisions) 9*428^3+1 = 705624769 is prime! (trial divisions) 1*428^32+1 is prime! (85 decimal digits) Time : 9.273 ms. 3*428^15+1 is prime! (40 decimal digits) Time : 9.067 ms. 4*428^14+1 is prime! (38 decimal digits) Time : 13.575 ms. 5*428^21+1 is prime! (56 decimal digits) Time : 9.341 ms. 7*428^20+1 is prime! (54 decimal digits) Time : 9.544 ms. 9*428^1665+1 is prime! (4383 decimal digits) Time : 156.265 ms.  Now, the "puzzle" is that I didn't find any prime for k=2, although I sieved to 1T and I cllr it to n=69133 - still running. (I am not so happy with the prime for k=4 also, as that is long known, and not a "new find", hehe, but I didn't do any action in that direction. ) One outcome from this futile playing with numbers is that I uncovered a small bug in cllr. My first sieving file was including 10*428^n+1 too, and it was sieving from n=0, therefore after srsieve kept 10*428^0+1 (which is prime) and eliminated all the other, so in the resulted sieved file (I stopped srsieve at 1e8 and continued with sr2sieve, then split and used sr1sieve for 2 and 8) - so in resulted file after first application of the srsieve, the 2*428^1+1 (=857, prime) followed after 10*428^0+1 (=11, also prime). In this very particular situation, cllr is testing the first one, and says it's prime, but is skipping the other one (i.e. misses the prime 857). Now I know this is a buggy situation, which will never happen in real life, but I wonder which other primes it can miss... Last fiddled with by LaurV on 2015-12-13 at 04:35

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