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-   -   46k sieve, max. n = 5M (https://www.mersenneforum.org/showthread.php?t=12432)

Cruelty 2009-09-12 13:00

46k sieve, max. n = 5M
 
The following k have been chosen for this sieve:[code]51 from n=1.7M
57 from n=1.7M
61 from n=1.7M
65 from n=1.7M
73 from n=2M
75 from n=1.5M
79 from n=1.12M
83 from n=1.12M
87 from n=1.7M
89 from n=1.12M
91 from n=1.12M
111 from n=1M
115 from n=1M
117 from n=1M
119 from n=1M
125 from n=1M
129 from n=1M
135 from n=1M
149 from n=1M
155 from n=1M
157 from n=1M
165 from n=1M
175 from n=1M
179 from n=1M
185 from n=1M
191 from n=1M
201 from n=1.2M - reserved by VBCurtis
207 from n=1.2M - reserved by VBCurtis
209 from n=1M
213 from n=1M
215 from n=1M
229 from n=1M
231 from n=1M
237 from n=1M
241 from n=1M
249 from n=1M
261 from n=1M
265 from n=1M
267 from n=1M
271 from n=1M
273 from n=1M
279 from n=1M
285 from n=1M
291 from n=1M
293 from n=1M
443 from n=1044006 - reserved by VBCurtis[/code]
The initial file sieved till p=2T is ~20MB large (6MB after compression) and is available upon PM request sent to either me or VBCurtis. Ranges below p=10T are reserved by me VBCurtis and Kosmaj.
Anyone interested in helping out is welcome. Minimum reservation range is p=1T, which takes ~4 weeks to complete on a single 1.8GHz C2D core under 64bit linux.
We are looking forward to ideas concerning this sieve and future reservations of sieved k / ranges.

em99010pepe 2009-09-12 18:19

Cruelty,

You can also add the k's (123, 153, 159, 171, 183, 189, 219, and 225) from the 9Ks drive.

Carlos

Thomas11 2009-09-15 16:18

Cruelty,

is there a reason for NOT taking k=113 from n=1.5M?
I released this k quite a while ago, and (as far as I know) nobody else has taken it yet.

And there is also k=29 at n=2M...

Cruelty 2009-09-15 18:10

There is no particular reason why any "k" is in this sieve or not, however at some point of time decision was needed to go forward rather than think which other "k" can be also included. The speed of this sieve is also a discouraging factor when it comes to making it even bigger...

em99010pepe 2010-03-09 21:23

I have a question. Will the next drive with these numbers be available within 5-6 months? I just need a yes or no answer.

Carlos

VBCurtis 2010-03-10 00:40

Carlos-
That depends entirely on how many people help with the sieve. If you wish to add a core to our sieve effort, I imagine we'd be far enough to begin 1.0M-1.1M work sometime this summer. We won't be at the optimal sieve depth, but the optimal depth is truly massive for a sieve this large. If you want to participate in testing these, it would be fair to help with the sieve.

A 1T range for this sieve takes about 3 weeks on a Core2-2.0. I think Kosmaj/Cruelty are in the 20-25T range right now with the sieve; I've only done 4T of the sieving to help out, because I plan to reserve a couple of these k's when they're ready. I'm trying to do 10-15% of the sieving, because I plan to test 5 to 7 of the k's including the couple already reserved to me (201,443, I think one other).

50T is not deep enough to get testing started, so at the current rate we will not be ready to go in 6 months.
-Curtis

VBCurtis 2010-03-10 01:08

Sieve speed and efficiency
 
To give an idea of how large a project this is-
There are roughly 3.7M candidates in the sieve. At 20T, my stock Core2-1866 (64 bit ubuntu) takes about 150s to find a factor. An LLR test of 1.0M on this machine takes ~1500 sec. If every k started at 1.0M in the sieve, this would imply a 200T depth before LLR is equal to factoring. Luckily, the 1.0-1.1M range is only half the k's, meaning half the sieve depth in principle.

This means 100T should be our target to begin LLR at 1.0M, and 150T or more for 1.1 to 1.2M. This is not the optimal sieve depth, where optimal means the depth that produces the shortest total project length to test all candidates. Optimal depth is so large it's depressing- 160T to get started, 320T at 1.1M, 450T or so at 1.2M. By 1.5M, we "should" be at 650T!!

This is what Cruelty referred to when he said we had to stop including k's somewhere.

Where is the blistering sheep when we need him?? Sheep, I hope you are healthy and working somewhere- you disappeared after discussing some life and wellness challenges with me.
-Curtis

Cruelty 2010-03-10 12:44

[QUOTE=VBCurtis;207893]There are roughly 3.7M candidates in the sieve. [/QUOTE]To be more exact, there are approx. 7.5M condidates in the sieve file now :wink:

em99010pepe 2010-03-10 13:52

I will help sieving with my 8 cores 64-bit when we complete the 6th drive.

VBCurtis 2010-03-10 21:16

Carlos-
Thanks for your offer to help. But we don't want to finish the 6th drive before we sieve the big file- that would leave us with no megabit tests to offer people (well, lower-1M range, ignoring k=15/17). That's why we dedicate 1 or 2 cores each to the sieve; the hope is it would be ready before we run out of the other drives.
We have tried to create and manage the drives so there is a selection of exponent ranges to test at any time. Ideally, we can release 1.0-1.1M from this sieve before the 6th drive reaches 1.4M. Think of the drives as ways to get people like unconnected to stop by and help out- we want them to have as much choice as possible.

Perhaps once the 6th drive is near 1.3M, we can convince you to mix in sieving with finishing the drive.
-Curtis

VBCurtis 2010-03-10 21:19

[QUOTE=Cruelty;207938]To be more exact, there are approx. 7.5M condidates in the sieve file now :wink:[/QUOTE]

That's what I get for quoting numbers from memory. Thanks for the correction!

That's a lot of megabit tests! For homework, estimate how many years (centuries?) it would take you (any of you) to finish LLRing the file working alone.
-Curtis


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