20160616, 15:36  #1376  
Sep 2011
Germany
2×3^{2}×151 Posts 
Quote:
I have one more prime in my list which I have forgot to add: 72344*52^743481 I will resend you the primefile for this base. There are 99 remain. 

20160616, 17:00  #1377 
Sep 2011
Germany
2·3^{2}·151 Posts 
Reserving R94 to n=1M (586.7k1M) for BOINC

20160617, 00:36  #1378 
Jun 2008
Wollongong, .au
3·61 Posts 
S49
S49 has two remaining k at n=600K. I'll try to extend that out to n=1M.
Since there are only two k remaining, how far should I go with sieving? When removing a factor take 50%? 80%? of the time to complete a primality test at n= ~1M? 
20160617, 06:17  #1379  
Dec 2011
After milion nines:)
2575_{8} Posts 
Quote:
On the other side, if you find prime at beginning of your search then you will have many candidates removed... Decision is yours :) 

20160617, 15:21  #1380  
"Curtis"
Feb 2005
Riverside, CA
2×3×19×41 Posts 
Quote:
However, you are not planning to test the entire file if you find a prime, half the remaining tests will not be run. You could use the heuristic for chance of finding a prime, and solve for optimal sieve time; or you could take a wildassguess and sieve to a point somewhat below 75% of 1M testing time and call it good. My WAG is 10% chance of prime in the entire file, so I'd sieve to about 70% of the 1M testing time; remember that optimal sieving *barely* matters in overall project length; you could get away with 50% or 100% and it won't make very much difference. 

20160617, 17:00  #1381 
Dec 2011
After milion nines:)
5×281 Posts 
If I may say: that logic is OK if you have many CPU cores. But if you have limited number of CPU cores , than every candidate removed by sieve is at least one hour less on fast AVX core

20160617, 17:41  #1382 
Just call me Henry
"David"
Sep 2007
Cambridge (GMT/BST)
2×2,909 Posts 

20160617, 22:24  #1383  
"Curtis"
Feb 2005
Riverside, CA
2×3×19×41 Posts 
Quote:
Are you saying a factored candidate will save more than one hour on your AVX core? Then you should sieve until it takes the sieve an hour or so to factor a candidate. I still don't get what you are trying to say. 

20160618, 06:36  #1384 
Jun 2009
683 Posts 
As somebody stated before, optimum sieve depth is impossible to determine as we hope we don't need to test the whole candidate file. I've had files that I sieved from n=1M to n=2M only to find a prime at n=1.05M and all the sieving I did was basically wasted.
That's why I do some basic sieving, test a few candidates at different nlevels to get timing information and then switch from sieving to LLR and back and forth, depending on what is faster. 
20160618, 12:36  #1385  
Dec 2011
After milion nines:)
5×281 Posts 
Quote:
Yes, that is what I try to say. We all hope that prime will be at beginning of the file we process. But what if it on the end, or even there is no prime in our range. In that case, every candidate removed with sieve is less to process. 

20160619, 13:11  #1386 
Sep 2011
Germany
101010011110_{2} Posts 

Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Bases 5011030 reservations/statuses/primes  KEP  Conjectures 'R Us  3828  20210227 09:19 
Bases 251500 reservations/statuses/primes  gd_barnes  Conjectures 'R Us  2257  20210227 09:18 
Bases 101250 reservations/statuses/primes  gd_barnes  Conjectures 'R Us  890  20210224 18:35 
Riesel base 3 reservations/statuses/primes  KEP  Conjectures 'R Us  1081  20210223 16:13 
Bases 432 reservations/statuses/primes  gd_barnes  Conjectures 'R Us  1431  20210218 16:05 