20200629, 13:20  #353  
Random Account
Aug 2009
1980_{10} Posts 
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20200630, 15:42  #354 
"Viliam Furík"
Jul 2018
Martin, Slovakia
2^{3}×5×17 Posts 
Hello, I would like to test primes for k=20020913 (my birthday date ). Could somebody please guide me to how far sieve, and what program to use? I have Radeon VII, RTX 2080Ti, and Ryzen 9 3900X available for testing. I would also like to ask if there is any difference between searching in k=20020913 and k=2002913?
In case there isn't a difference, I reserve the k=20020913, and the other one is for the future me. 
20200630, 16:15  #355 
"Curtis"
Feb 2005
Riverside, CA
2^{7}×3×13 Posts 
I suggest you make a short project out of n=1 to n=400k to find small primes, and then decide how large an 'n' you want to set up a sieve for.
For the small primes, srsieve or newpgen to create the sieve file, then sr1sieve because it's faster than the other two. One generally sieves until the average time to find a factor is equal to the LLR time for a candidate 70% of the way from nmin to nmax; in this example, that would be at n=280k. The reason I don't give a sieve depth number is that the proper depth depends quite a bit on how many candidates remain in the sieve, which is a way of saying the weight of the kvalue. Different k's have different patterns of small factors that eliminate a bunch of candidates, so some k's need sieve depths an order of magnitude larger than others. LLR is the primalitytesting program; there is a version for GPU, but it's best described as alphaversion quality. Rogue has srsieve2 package of programs, some of which are GPUenabled; peruse that thread (or wait for someone who knows more than I do here) to see if you can sieve on GPU and test LLR on CPU. Large sieve ranges are more efficient than small ones; after you run to 300k or 400k for the first sieve and test all those candidates, I'd make a second sieve that covers any range you are likely to ever test 400k to 4M isn't crazy, but that's coreyears of searching; 400k to 2M could be completed in a few months. The second k will yield different primes, so "saving" that for futureyou makes sense. Happy hunting! 
20200630, 18:54  #356 
"Viliam Furík"
Jul 2018
Martin, Slovakia
1010101000_{2} Posts 
First prime, before any tests!
BTW, before any tests, I found 20020913*2^121 to be prime. I simply calculated the value and used an online tool (https://primes.utm.edu/curios/includes/primetest.php) to find out whether it is prime.

20200701, 08:58  #357  
"Alexander"
Nov 2008
The Alamo City
1366_{8} Posts 
Quote:


20200701, 19:06  #358 
"Viliam Furík"
Jul 2018
Martin, Slovakia
2^{3}·5·17 Posts 
I meant the GPUs for LLR testing. Is there a program for GPU testing, not sieving? Especially if it had properties as gpuOwl, it would be really fast on Radeon VII.

20200701, 19:13  #359  
Sep 2002
Database er0rr
3,853 Posts 
Quote:
I asked Yves Gallot about Proth on GPUs, downloaded and compiled the source and it was equal to 4 CPU cores, whereas Mersenne is like 40 cores 

20200701, 23:28  #360 
Random Account
Aug 2009
2^{2}·3^{2}·5·11 Posts 

20200702, 09:18  #361  
"Alexander"
Nov 2008
The Alamo City
2·379 Posts 
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20200702, 12:33  #362 
Mar 2007
Estonia
2^{2}×37 Posts 
llrCUDA works, I have been running one for months. But it's slow, much slower than a CPU in the same class .
I am getting 1.1ms per iteration on n=3.8M on a 1080TI While the same n is getting 0.271 ms per iteration on 5 threads and 0.7ms on 1 thread on an i76700K Last fiddled with by kuratkull on 20200702 at 12:39 
20200714, 08:05  #363 
"Alexander"
Nov 2008
The Alamo City
2×379 Posts 
My work on filling in gaps for (near)Woodall k's has reached n=300k. Three primes were found:
A prime for k=197673 was found earlier. The list of k's tested to n=300k is:
Updates will be posted to PrimeWiki shortly. I'm also reserving k=1993191 (the latest nearWoodall k) for n < 3986382. Last fiddled with by Happy5214 on 20200714 at 08:17 
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