We have entered the "optimal sieve zone". Actually, we've been floating around it for some time since the last prime was found back in June. Please consider this the first notice to anyone on the cusp of their next badge level (20K, 200K, 1M, 2.5M).

It is currently unknown "exactly" when the sieve will end. However, we can guarantee another four weeks (REVISED sooner: to at least 13 Oct 2010). In the meantime, we'll be investigating to pinpoint an exact stop date. And yes, we are taking the Calendula Challenge into consideration so people won't be forced to make a choice between the two. :)

This is a major accomplishment for both the Prime Sierpinski Problem and the Seventeen or Bust projects. The PSP/SoB sieve at PrimeGrid was announced on 13 Oct 07. That date this year might be a very fitting day to end the sieve. :)

The official classification of this will be a suspension and not a termination. Should "improved" sieving methods come up in the future, this sieve will be reviewed for continuation. EDIT: And of course, should there still be k's remaining as we approach 50M, we'll need to resume sieving for n>50M. :)

We'll update everyone as soon as we know more.
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It is currently unknown "exactly" when the sieve will end. However, we can guarantee another four weeks. In the meantime, we'll be investigating to pinpoint an exact stop date. And yes, we are taking the Calendula Challenge into consideration so people won't be forced to make a choice between the two. :)

This is a major accomplishment for both the Prime Sierpinski Problem and the Seventeen or Bust projects. The PSP/SoB sieve at PrimeGrid was announced on 13 Oct 07. That date this year might be a very fitting day to end the sieve. :)

Color me confused. Today is the 18th of September, you're saying there's at least 4 weeks to go (that takes us to the 6th of October), and you're saying (I think) that you're extending that by 13 days to allow for the Calendula challenge. That takes the earliest possible end date to October 29th.

Then the next paragraph says it might end on the 13th.

So I'm confused.

By suggesting a symbolic end date, I should have revised the initial guarantee. The guarantee is at least until the 13th of October, 2010.

I am wondering about how "optimal" is determined across all sieves. I assume that it is generally the same method...namely that the rate of factors being found falls below the rate of computational time to find actual primes with LLR, etc.

However, this leaves me with a question...if you will permit me the use of an old cliche in analogy...

Let us assume that we are dealing with the old "...forest for the trees" analogy where each "tree" is a number that is or is not prime. The prime "trees" are much rarer than non-prime "trees", and we have two methods for observing this difference. One method is to look directly at the primeness of each "tree"; in the analogy perhaps by walking to each tree and counting the branches. The second way is to observe the non-primeness of the tree in some manner (i.e., the sieve process); for the analogy, let's say by observing some characteristic of the leaves--say their color. The way that I understand the "optimal" decision is being made would be, in the analogy, to see when it takes the same amount of time to count the branches as to discern the leaf color of each "tree"?

If this is correct, then I wonder if it is really optimal for all sieve conditions. For example, the time of calculation of each workunit in the TRP LLR and sieve applications is similar, essentially like walking to each "tree", and thus the time to assess each "tree" by each method can be compared directly for efficiency. However, in the case of the PSP/SoB sieve vs. PSP LLR and SoB LLR, these times are drastically different (about 35minutes on average for the sieve vs. 90 hours and 286 hours for the LLR's. respectively). In the analogy, this would seem to be like the difference of walking to each "tree" to see if it is prime vs. flying over the "forest" in a plane and observing whole sections that are not prime. More directly said, in BOINC, I believe that it is fair to say that individuals are more likely to chose to crunch smaller/shorter work (at least with a preference for no more than a 1-day/24-hour workunit). Thus, even if the actual "tree by tree" rate of sieving is no faster than the LLR approach, isn't there an efficiency of more individuals being willing to sieve shorter work (essentially eliminating whole sections of the "forest")? Or has this already been factored into determining what is "optimal"?

Edit: or said more mathematically, let's say that you have 100 crunchers. All 100 are willing to crunch (and have the equipment to handle) the short sieves. If all 100 are also willing and capable of crunching the much longer LLR, then the direct application/computational efficiency can be directly compared. However, if only 25 are willing and/or have the capability to LLR, then wouldn't the optimal sieve depth need to be 4 times the actual application/computational efficiency?
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141941*2^4299438-1 is prime!

Conversely, however, people do want to find prime numbers, and sieves never will. That makes the LLRs more desirable. Finding one of these primes would be a big, big event. So there's also some pressure pushing crunchers towards the longer WUs.

If I wasn't playing "find the badge,", I would most likely be running some combination of SoB, PSP, and ESP LLRs.
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My lucky number is 75898⁵²⁴²⁸⁸+1
(I am NOT an administrator anymore, so please don't PM me with questions. I can't help.)

toms83, looking at your computer list it would only take some days to get a bronze badge if you want this one.

isn't there an efficiency of more individuals being willing to sieve shorter work (essentially eliminating whole sections of the "forest")? Or has this already been factored into determining what is "optimal"?

Well I've only got 2 (64-bit) cores @2.9GHz, and am barely over the bronze badge threshold. At about 24 minutes per WU, it'll take me at least 45 days 24/7 to get to 200K. Realistically that means more like 90 days. >>punt<<

I certainly support shutting things down if the science warrants it; I just wish I had poured some more time in to this earlier. Oh well.

--Gary

Fair enough, I'm doing same actually, making a quick push for silver before resuming LLR elsewhere... but there's already closed projects where new joiners can't get a badge at all. We can only crunch what's there.

I wonder if John's initial guarantee for 13th of October 2010 took under consideration that "quick push" by so many of us...

Two quick questions:
1.During The Calendula Challenge PSP sieving project will be available or not?
2.What other subproject could face suspension or termination in upcoming months ?

13 October is approaching

This will be the last insertion date for PSP (Sieve) before it is suspended. Until then, the queue will be kept full for anyone wishing to complete their last effort on this project.
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Are you considering to use the new version of LLR, and take advantage of the 33% speedup to further increase the progress of this project?

KEP

It'll be a tight timeline for me to get silver. My estimates put the 200,000 credit achievement at about 12 hours into October 13th. Hope the reservoir can stay filled that long...

It'll be a tight timeline for me to get silver. My estimates put the 200,000 credit achievement at about 12 hours into October 13th. Hope the reservoir can stay filled that long...

Hmmmm.

Well, you can set a 10 day cache on your computer, but, yes, the server can be set to limit the number of WUs, so depending on your machine you may not be able to download 10 days worth without some fudging around.

The question, however, had to do with missing by about 12 hours, so 300 WUs should be enough unless you're crunching more than 25 WUs/hr on your machine(s).

If you want to fudge it and get more (John, don't look!), you can set up virtual machines on your mutli-crore crunchers. They'll appear as separate computers to the server, so the VM and the host machine can both get 300 WUs. You might even be able to run multiple VMs at once, but I've never tried that. In theory, you could run one VM for each core, each with 300 WUs. You'll need about 500 meg of ram per VM, however.
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My lucky number is 75898⁵²⁴²⁸⁸+1
(I am NOT an administrator anymore, so please don't PM me with questions. I can't help.)

A few hours left

This will be the last insertion for PSP (Sieve) before it is suspended. Increase your cache if you're not going to make it. However, at the rate of the pass couple of days, there will only be 2-3 days of work left after this last insertion.

Congratulations to everyone who has participated in the sieve. It's a wonderful milestone to reach.
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PSP Sieve Update

The buffer is quickly heading towards 0. Currently, there are less than 90K tasks remaining. Get'em while you can. :)
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PSP Sieve Update

Currently, there are less than 20K tasks remaining. Less than 24 hours of work at our current rate.

EDIT: And now as of 18 Oct 2010 20:26:12 UTC there are none! :) Available: PSP/SoB (Sieve) 0

All that's left now are the resends. Currently there are 32681 tasks in progress.
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PSP Sieve Update

As of 18 Oct 2010 20:26:12 UTC there are 0 tasks remaining in the work buffer! :) Available: PSP/SoB (Sieve) 0

All that's left now are the resends. Currently there are 518 tasks in progress.

History: work in progress
29 Oct: 518 tasks
28 Oct: 1028 tasks
27 Oct: 2415 tasks
24 Oct: 3317 tasks
23 Oct: 6419 tasks
22 Oct: 7546 tasks
21 Oct: 12604 tasks
20 Oct: 13396 tasks
19 Oct: 15262 tasks
18 Oct: 32681 tasks
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PSP Sieve Update

Currently there are 0 tasks in progress.

History: work in progress
03 Nov: 0 tasks
02 Nov: 4 tasks
30 Oct: 354 tasks
29 Oct: 518 tasks
28 Oct: 1028 tasks
27 Oct: 2415 tasks
24 Oct: 3317 tasks
23 Oct: 6419 tasks
22 Oct: 7546 tasks
21 Oct: 12604 tasks
20 Oct: 13396 tasks
19 Oct: 15262 tasks
18 Oct: 32681 tasks
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PSP (Sieve) is officially suspended

The last few remaining tasks are now complete. The official classification of this will be a suspension and not a termination. Should "improved" sieving methods come up in the future, this sieve will be reviewed for continuation. EDIT: And of course, should there still be k's remaining as we approach 50M, we'll need to resume sieving for n>50M. :)

This is a major accomplishment for both the Prime Sierpinski Problem and the Seventeen or Bust projects. In a little over three years (13 Oct 2007 to 3 Nov 2010) we helped advance the sieve from 1.5P to just over 83.1P. Also, the PSP (Sieve) was the inaugural project in the Challenge Series starting in 2008 and was a mainstay each year with the Ides of March Challenges. Now that it has joined Caesar, we'll have to find another project to replace it. :)

Thank you to all who contributed to this project.
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