20130423, 16:21  #1 
Jun 2012
2×53 Posts 
Help with sieving
Do you need any help with sieving Kosmaj? I'd be happy to throw a core or two at that for a while, just to give me something to do.
Is there a specific range that I could sieve, or just to do, say, n = 3m to 3.25m? 
20130423, 16:54  #2 
"Dave"
Sep 2005
UK
2^{3}×347 Posts 
We are using sieve files provided by PrimeGrid who are sieving k=39999 for both n1 and n+1. n=36M is currently sieved to 274P (274e15) and they are still sieving.

20130423, 19:21  #3 
Jun 2012
2×53 Posts 
Ok then  I guess PrimeGrid are going to trump anything I can do  ah well.

20130426, 03:06  #4 
Nov 2003
3622_{10} Posts 
Hi f1,
Thanks for your kind offer. As the others said, k<10000 are already extensively sieved, but you can help us extra sieving our candidates from our lowweight 10th drive, featuring k>10000. Let me know if you are still interested. Thanks! 
20130427, 16:07  #5 
Jun 2012
2×53 Posts 
Sounds good to me! I can get started at any time.
EDIT: Having sewn the whole range together, I'm at 2.5M p/sec. So, I'm looking at 10G/hr or 1T/100 hrs of wall clock time. Expecting 1 factor every twenty hours, am I going to be working efficiently at this range? Last fiddled with by f1pokerspeed on 20130427 at 16:29 
20130427, 16:39  #6  
"Carlos Pinho"
Oct 2011
Milton Keynes, UK
2·3^{2}·281 Posts 
Quote:


20130427, 16:51  #7 
Jun 2012
2×53 Posts 
The lowest candidate in the file takes ~1,100s (by quick extrapolation)  so this range looks to be optimal right now. The highest candidate is roughly the same  I'd say it's even oversieved ever so slightly.
It might be easier for me to just presieve some later ranges, say n = 2m > 3m. If that could be accommodated for, I would be happy to do some work on it. Last fiddled with by f1pokerspeed on 20130427 at 16:53 
20130427, 21:33  #8 
Nov 2003
2×1,811 Posts 
Hi f1
Thanks again for your kind offer. I'm enclosing the latest sieving file with candidates from the 10th drive, starting at n=1312k, sieved to 75T. We are also preparing another file with high weight Ks for sieving. When it's ready we'll ask you to kindly stop this one and sieve the new one. If you don't mind, can we establish email connection for easier exchange of files. Thanks! 
20130427, 22:07  #9  
"Curtis"
Feb 2005
Riverside, CA
1010100000111_{2} Posts 
Quote:
Generally speaking, sieve ranges smaller than a factor of two from nmin to nmax are not very efficient. This is an effect of the sieve speed scaling with the squareroot of nrange, combined with LLR testing scaling with the square of n. So, while this sieve from 1300 to 2000 is probably properly sieved, you are correct that not only would sieving 23m be of use, but once 75T is reached you could combine the current sieve and run from 1300 to 3000 with more efficiency than either 13002000 or 20003000. If demand supported it, I'd even go with 24 million. However, that would be quite a large project, and it's not clear that this lowweight drive would have sufficient interest to bother with a new sieve up to the 100T range. With primegrid sieving over 1000 times deeper (10 bits, at almost 2% candidates removed per bit, so 15 to 18% fewer candidates than 100T), it's hard to believe we'll have sufficient interest to justify a massive effort on the 10th drive. That said, I'll be happy to participate in a future highweightk sieve and drive, and hope you will too. Curtis Last fiddled with by VBCurtis on 20130427 at 22:08 

20130427, 22:43  #10 
Dec 2011
After milion nines:)
2^{3}·3·5·13 Posts 
What is "chance" to find any prime in this low weight Ks?

20130427, 23:41  #11 
"Carlos Pinho"
Oct 2011
Milton Keynes, UK
5058_{10} Posts 
Last fiddled with by pinhodecarlos on 20130427 at 23:41 
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