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Old 2008-12-26, 09:10   #1
gd_barnes's Avatar
May 2007
Kansas; USA

100111110000002 Posts
Default Sieving drive for k=1005-2000 n=200K-500K

This is a sieving drive for k=1005-2000 and n=200K-500K. If you can spare the machines, we are asking that people dedicate 15-20% of their CPU resources to the effort so that we can complete it in ~3 weeks. I will personally be putting 2 of my newer 64-bit Intel quads on it.

The reason for the priority is because the 5000th-place prime on the top-5000 site is rising rapidly, largely as a result of us finding so many primes on our 1st drive and now the 5th/6th/7th drives. We would like to begin LLRing the effort before the 5000th place prime reaches n=350K, which at the current rate will be in about 3 weeks.

Bruce started the sieve on n=50K-500K several months ago and got it up to P=160G. Ian has accelerted the pace in the last 2 months. Our current sieve depth is P=1400G and Ian is currently working on P=1400G-1800G. I have determined the optimal sieve depth for the n=50K-200K range to be about P=1600G so we will break off that range and not include it in this effort. In the mean time, we need to continue sieving n=200K-500K starting from P=1800G.

As you can guess, even for the smaller range of n=200K-500K, the file is huge. Even in ABCD format, the entire n=50K-500K range is 32 MB and the n=200K-500K range that we will be working on is 21 MB after removing all factors up to P=1400G. Zipped, it should be about 6 MB. I provide a link to the zipped file below. If it is a problem for you to pull it off of the link, let me know and I'll Email it to you.

We will likely sieve to about P=6T (6000G) and then break off n=200K-350K. We'll then need to continue sieving n=350K-500K. A rough estimate for the optimum sieve depth for that final range is P=9T-10T (9000G-10000G).

Ian has been sieving P=200G per core and it has been taking him ~10-11 days using 64-bit sieving. Assuming that you have new cores and a 64-bit O.S., I would suggest taking P=100G ranges per core to start with to guage the sieving speed of your machine. If his machines are a guage, that would take you 5-6 days for each core. For slower/older machines or if you. have a 32-bit O.S., I would suggest half of that.

sr2sieve is what we will use. Let us know if you need the executable or more detailed instructions on using it.

I prefer that we use the more "modern" method of sieving by specifying the ranges and file name at the command prompt as in:

sr2sieve -p 1800e9 -P 2000e9 -i sieve1005-2000-200K-500K.txt

The above would be if you were sieving P=1800G-2000G. The file is listed after the "-i" command and is the actual file name that will be in the zipped file at googlepages. Feel free to name it something shorter if you want or use the "srwork" older convention where you don't have to specify a file name.

When complete, you should have a factors.txt file. Just post the file here in this thread or if it is too big, please Email the file to me at:
gbarnes017 at gmail dot com

Sieve file:
1005-2000-200K-500K [factors removed up to P=3800G]

  P-range     reserved by     Status
   0G- 160G   Brucifer        complete
 160G-1800G   MyDogBuster     complete
1800G-3400G   gd_barnes       complete
3400G-3800G   Flatlander      complete
3800G-4000G   MyDogBuster     complete
4000G-4050G   Mini-Geek       complete
4050G-5850G   MyDogBuster     complete
5850G-5900G   mdettweiler     complete
5900G-7100G   gd_barnes       complete
7100G-7200G   Mini-Geek       complete
7200G-8200G   IronBits        complete
8200G-8600G   gd_barnes       complete
8600G-8800G   glennpat        complete
8800G-10000G  gd_barnes       complete
It won't be neccesary to reserve ranges for P>10000G.
After Ian is complete to P=1800G, we will start an 8th drive for n=50K-350K beginning with the range of n=50K-200K. After we have completed all sieving, we will start a 9th drive for n=350K-500K. n=200K-350K will be done after n=50K-200K in the 8th drive.

There's a lot of work to do so let's get crackin'. Once this is done, we'll have a drive where we'll likely be finding a gob of top-5000 primes each day!


Last fiddled with by gd_barnes on 2009-01-17 at 16:03 Reason: update status
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