Assignments?
 

The range {10330000 12830000} :question: has had 3 unfinished candidates for ages.
Isn't anyone doing these?

[QUOTE=Bob Silverman]The range {10330000 12830000} :question: has had 3 unfinished candidates for ages.
Isn't anyone doing these?[/QUOTE]

Yes, they are all assigned by primenet. One seems to be close to expiring, and will most likely be finished within a couple days of expiration. The other two are making progress, however, only one has a chance of finishing in a semi-finite amount of time.

I think we need to ask George to do a formal release on at least one of the exponents which shows over 1000 days to completion. Otherwise it is becoming an attractive target to poachers.

I don’t understand why there are no faster re-assignments for such exponents. We are not even loosing something. Should the result of the original come in it would be used as double-check. So we only would run the double-check before the first LL is in.

Matthias Noch

well, these exponents were assigned to the respective users first and if any one of these exponents is prime, we do not wish to e unfair to them and take away their chance of discovering the prime. However, fair does not mean waiting forever and George usually releases exponents that have not had any work done or are being worked on very very slowly, once every 6 months or so. He will probably be doing a release of these numbers too. But in the meanwhile I hope no one wil take it upon himself/herself to complete them as that is "poaching" and we all know that "poaching is very bad" :)

Will one or more of the complainants please refresh my understanding of precisely what harm is being done by these slow-completers?

Apparently some of the complainants feel impatience when they view the progress reports of the slow-completers. But those are only internal feelings generated by the complainants themselves, not some real damage done by the slow-completer. So, what actual harm is done in reality by any slow-completer?

I've seen the discussion of errors caused by cosmic rays, and that the likelihood of such errors is proportional to the length of the L-L run. In those discussions it is apparently assumed that slow-completers pose a greater risk of turning in erroneous reports due to such errors.

But the likelihood of cosmic-ray-induced errors is also proportional to each computer's sensitivity to such errors. The slower computers are likely to be those with larger mask sizes used in printing their circuits, thus [b]reducing[/b] their sensitivities to cosmic-ray damage, relative to the faster systems with thinner circuitry in which a cosmic-ray hit can affect a larger fraction of the area of a component.

- - - - - - -

Bob, Matthias, anyone else -- can you demonstrate actual real harm (not just an effect on someone's feelings) done by a slow-completer?

< :devil: advocate >

Cheesehead,

Perceived lack of progress of the whole project can make people feel like nothing is happening and that the project is stalling. If people feel that the project is stalling out, they may decide that their cycles have a better impact else where. The rats-jumping-off-a-sinking-ship syndrom is of no help to the project.

A smooth progress milestone production is a good thing. People don't like to see big spikes and then slow speed. Whiplash ain't fun.

< / :devil: advocate >

Okay, that's another feelings example.

Perhaps some of our mathematically-simple progress indicators are ill-suited (in terms of feelings generated by impatient observers :) to the reality of what they're measuring. GIMPS progress, depending on the efforts of human volunteers using systems with a wide range of capabilities, is necessarily always going to have some stragglers. That doesn't mean GIMPS isn't progressing smoothly.

Proposal for the GIMPS status page: (1) Instead of always showing the single lower bound of DCs, which progresses in jerks, show only the average exponent of the trailing 100 (or 41 or whatever) DCs. This average would, I think, increase relatively smoothly and not give the misleading impression of jerky progress. (2) Stop showing the countdown of exact number of tests needed to prove Mxx is Mxx -- anyone who wants to know these numbers can derive them from the various report files. When the countdowns reach the single digits, they're not really informative -- they're just provocative to the impatient.

[QUOTE=cheesehead]Bob, Matthias, anyone else -- can you demonstrate actual real harm (not just an effect on someone's feelings) done by a slow-completer?[/QUOTE]

Hi,

you asked what harm slow-completer are causing. I have three points:

1.) The project is not only about finding isolated new Mersenne primes, but although about proving that these new found are the only ones in the range the current GIMPS is covering. We want to find all Mersenne primes in the data range and prove that they are the only ones. That means that we need to cover all exponents below a given new Mersenne prime to prove that this one is the number 36, 37 or 41. If it takes years to finish one small exponent, which under today’s normal performance would take only 4 of 5 days to calculate, it is holding up the whole process without need. That doesn’t help to get a better understanding of the distribution of those Mersenne primes.

2.) It makes a bad impression about the organisation of the project when we can’t finish a data range in an acceptable amount of time. We are crunching very large numbers, but fail to finish much smaller exponents. That doesn’t look good.

3.) We are doing a very abstract stuff here. To keep people motivated one needs to reach small and big milestones from time to time. As we don’t find a new Mersenne every month other milestones have to keep people interested. Like :

All exponents below 8,715,700 have been tested and double-checked.
All exponents below 12,441,900 have been tested at least once.
Countdown to testing all exponents below M(13466917) once: 4
Countdown to testing all exponents below M(20996011) once: 9,549
Countdown to testing all exponents below M(24036583) once: 42,739
Countdown to proving M(13466917) is the 39th Mersenne Prime: 39,154
Countdown to proving M(20996011) is the 40th Mersenne Prime: 204,395
Countdown to proving M(24036583) is the 41st Mersenne Prime: 271,351

If we loose one normal cruncher with an up-to-date PC due to frustration about no progress we are loosing much more power then when we loose 10 angry slow-crunchers because their exponents were reassigned in time to keep the project rolling.

It will close to be impossible to keep the project running in the much higher areas with only slow-completers. We need as much high-power as we can get now that we really working big numbers.

Best,

Matthias C. Noch

[QUOTE=Matthias C. Noc]If we loose one normal cruncher with an up-to-date PC due to frustration about no progress we are loosing much more power then when we loose 10 angry slow-crunchers because their exponents were reassigned in time to keep the project rolling.[/QUOTE]
Each time you loose one slow cruncher, there is a great cance you'll loose the rest of his machines too. (I have >200, a few of them are rather slow, but I don't want to see cycles wasted.) It is very discouraging when you find that the exponent you have been working on the last four months was poached, and I don't think you'll find that many people leaving the project because of a couple of exponents testing very slowly.

I think we should take another approach to handing out work. Let us decide how large exponents we want by the number of days it will take to complete it, and hand out exponents in lots of different ranges at the same time. This will let everyone make steady progress and see exponents complete regularly at the speed he or she decide. And let the server deny requests for exponents which will take more than 120 days or so to complete. We will make progress in all ranges at the same time, and if you believe that there is a good chance to find a prime in a specific range, you can choose exactly that range. Machines will last longer in the project (remember that every cycle count as long as the exponent is completed) and produce results longer. Shure we won't complete the lower ranges as fast, but we will have perfect work for all kinds of computers for longer. When there are no more exponents left to test at 120 PIII days, the PIIIs will get double checks from the higher ranges, while there is still work left for Pentium IIs in the lower ones.

[QUOTE=S00113]
I think we should take another approach to handing out work. [/QUOTE]

You assume that everyone joining the project has read the user manual and is able to select number of hours and kind of reservation.

I don't think so. Many people use to start an application just clicking on it, and to forget about it. They usually put default values in the boxes just to see "if it works".

To get rid of long-standing exponents, I think there should be an automated algorithm to calculate the effective CPU daily work, and request exponents based upon that algorithm.

Luigi

[QUOTE=S00113]And let the server deny requests for exponents which will take more than 120 days or so to complete.[/QUOTE]
What about people with slower computers that want to look for primes that are larger then the ones yet discovered?
Sure, it'll take forever for somebody with a 386 to do an LL test on a number bigger then M41, but if it isn't slowing somebody else's progress down, we shouldn't stop them.
If you're going to deny the longer requests, at the very least let anybody who wants tackle the longer exponents (although perhaps give them a warning that it'll take a while if it's going to take more then six months or so). They won't be slowing down the countdowns - in fact, it would speed up the countdowns by letting someone with a faster computer have a go.

Yes, assigning first time tests to the slowest computers may be a good idea since it would prevent them from holding up any milestones. (The "tested once" milestones are really not very important since we have so many errors.) And assigning first time tests to the REALLY slowest computers may prevent them from holding up any milestones for the first four years, or so.

[QUOTE=S00113]It is very discouraging when you find that the exponent you have been working on the last four months was poached...[/QUOTE]

Four month would be no problem, I was talking about those who need years or how nfortino wrote "only one has a chance of finishing in a semi-finite amount of time".

[QUOTE=S00113] think we should take another approach to handing out work. Let us decide how large exponents we want by the number of days it will take to complete it, and hand out exponents in lots of different ranges at the same time. This will let everyone make steady progress and see exponents complete regularly at the speed he or she decide. And let the server deny requests for exponents which will take more than 120 days or so to complete.[/QUOTE]

Yes, something like that would be good. I think a stricter expiration rule might do the trick too, e.g. if procress per week on a small exponent is not bigger than 5 % (except holidays), then a warning should be send, after three warnings the exponent should expire and returned to the pool.

[QUOTE=I_like_tomatoes]What about people with slower computers that want to look for primes that are larger then the ones yet discovered?
Sure, it'll take forever for somebody with a 386 to do an LL test on a number bigger then M41, but if it isn't slowing somebody else's progress down, we shouldn't stop them.
If you're going to deny the longer requests, at the very least let anybody who wants tackle the longer exponents (although perhaps give them a warning that it'll take a while if it's going to take more then six months or so). They won't be slowing down the countdowns - in fact, it would speed up the countdowns by letting someone with a faster computer have a go....[/QUOTE]

If one isn't holding up the progress I see no problem at all. In the higher ranges one year or more to complete won't matter in the foreseeable future. So there is no problem.

Best,

Matthias C. Noch

[QUOTE=Matthias C. Noc]
If one isn't holding up the progress I see no problem at all. In the higher ranges one year or more to complete won't matter in the foreseeable future. So there is no problem. [/QUOTE]

Apart from discovering M42 with one year of delay...

Luigi

[QUOTE=ET_]Apart from discovering M42 with one year of delay...
[/QUOTE]

Yes, maybe, but it will take a lot of time to prove that M42 is really M42 and not M44. IMHO the real worth of this project is that we are checking all exponents, and are not just adding some new, but isolated M-primes.

Best,

Matthias C. Noch

I think you are forgetting something very important.

This is a proyect we are all contributing as a TEAM, and I think we need everybody contribution. The sum of all contributions is what gives this proyect its impressive computing power...

If you think your supercomputers (which btw I really don't think you have) can do this work alone then please don't bother everybody else: Become LMHs and enjoy your superb speed.

Best Regards,
EMC

[QUOTE=Matthias C. Noc]Hi,

you asked what harm slow-completer are causing. I have three points:[/quote]
(... each of which explains how impatient people can affect the project, but none of which demonstrates any effect on the project by the slow-completers themselves, which is what I asked for! :-)
[quote]1.) The project is not only about <..snip..> If it takes years to finish one small exponent, which under today’s normal performance would take only 4 of 5 days to calculate, it is holding up the whole process without need.[/quote]
No, it isn't!!

Let's say the fast machine does the small exponent in 4 days, while the slow machine does it in 400 days. Then their relative speeds are 100 and 1. With the fast machine alone, total speed of GIMPS progress is 100 speed units. With both machines, total speed of GIMPS progress is 101 speed units, which is 1% faster. The slow machine is speeding up GIMPS, not slowing it down.

If the slow machine were not taking care of exponent A it is working on, the fast machine [u]would have to be diverted from working on a different exponent B in order to take care of exponent A[/u]. [u]That[/u] (i.e., elimination of the slow machine's contribution) would hold up the project for the time it would take the fast machine to work on exponent A instead of exponent B! It is the elimination of the slow machine, not its participation, that would hold up the project!

Who would advance the work on exponent B while the fast machine worked on exponent A? Do you ever take [u]that[/u] into account?

It seems to me that the objectors to the slow-completers systematically overlook that if the slow-completers were not participating, faster machines [u]would have to be diverted from other work[/u] in order to perform the work that the slow machines would have performed, thus [u]slowing down[/u] progress on the exponents that the faster machines would otherwise have been doing.
[quote]That doesn’t help to get a better understanding of the distribution of those Mersenne primes.[/quote]
Tell us how slowing GIMPS progress from a speed of 101 to a speed of 100 helps to get a better understanding of the distribution of Mersenne primes than continuing at speed 101 would get.
[quote]2.) It makes a bad impression about the organisation of the project when we can’t finish a data range in an acceptable amount of time.[/quote]
What is that acceptable amount of time? Who defines the acceptable amount? Will you admit that your argument is only about the emotions of impatient people, not about any real harm done by the slow-completers?
[quote]We are crunching very large numbers, but fail to finish much smaller exponents. That doesn’t look good.[/quote]
But we haven't failed to finish any much smaller exponent!! If you disagree, tell us one exponent which this project has "failed to finish". [i]Note that that can't include any exponent on which work is currently in progress, or else you're declaring that all of the thousands of assignments which are not yet completed are ones that we are "fail[ing] to finish". If you're saying that all the thousands of currently uncompleted assignments are failures to finish exponents, then your argument doesn't seem to be worth anything.[/i]
[quote]3.) We are doing a very abstract stuff here. To keep people motivated one needs to reach small and big milestones from time to time. As we don’t find a new Mersenne every month other milestones have to keep people interested.[/quote]
Okay. For the purposes of this discussion, I'll accept that.

But ever since this project's beginning, we [u]have[/u] been reaching small and big milestones all along, despite the participation of those darned slow-completers. In fact, the slow-completers have been helping GIMPS reach those milestones 1% or 2% faster than we would have without their help.
[quote]Countdown to testing all exponents below M(13466917) once: 4
Countdown to testing all exponents below M(20996011) once: 9,549
Countdown to testing all exponents below M(24036583) once: 42,739
Countdown to proving M(13466917) is the 39th Mersenne Prime: 39,154
Countdown to proving M(20996011) is the 40th Mersenne Prime: 204,395
Countdown to proving M(24036583) is the 41st Mersenne Prime: 271,351[/quote]
... and GIMPS will reach each of those milestones, just as it has been reaching earlier milestones all along.
[quote]If we loose one normal cruncher with an up-to-date PC due to frustration about no progress[/quote]
[i]No[/i] progress? What do you mean [i]no[/i] progress? GIMPS is making progress every day, so why do you write about "no progress"?

... and I note again that your argument is about the feelings of impatient people, not about any real harm done by slow completers. I'm not saying feelings are unimportant -- I'm saying that although I asked for arguments about real harm by slow completers, so far all I've gotten are arguments about feelings of impatient people. I just want folks to call a spade a spade.
[quote]we are loosing much more power then when we loose 10 angry slow-crunchers because their exponents were reassigned in time to keep the project rolling.[/quote]
But the project [u]is[/u] rolling. I haven't yet seen you offer any evidence that it isn't!!
[quote]It will close to be impossible to keep the project running in the much higher areas with only slow-completers.[/quote]
Why do you exaggerate? No one except you has said anything about running the project with only slow-completers.

Can't you tolerate the participation of a small percentage of slow-completers? Neither I nor anyone else has proposed that slow-completers would constitute a large proportion of participants -- it just ain't gonna happen. So what's your worry?
[quote]We need as much high-power as we can get now that we really working big numbers.[/quote]
I agree.

So why don't the folks with high power simply just continue to participate as they have been?

Do you want to lose 1-2% (or whatever it is) of GIMPS speed by eliminating the slow-completers?

Cheesehead, you have stated in a far more clever way my point of being a team.

I completely agree with you.
EMC

Back to the main issue, what is the projected time for the last 4 to finish ?

Years or months ? Or an aproximate date.

I think it's fair to say that, had it not been for the slow computers, we would not know that M24036583 is prime. Personally, I don't see any way for us to have gotten to test M20996011 either if it weren't for those "slow computers".

Plus, if you have 1000 slow computers running at the same rate as 100 new, fast computers, then those 1000 slow produce the same quantity of results in a given time as the fast 100. Since the slow 1000 are also not working synchronously, they are producing results just as if they were the fast 100, and really the only difference between the slow 1000 and fast 100 is the quantity of numbers that are being worked on. Were it not for the fact that this program's creators have allowed us to have access to information about specific numbers, it would be completely impossible to tell the difference between numbers done by slow and fast computers. (In other words, other computer speeds are irrelevant if you don't know their speeds, making their speed irrelevant even if their speed is known.)


Plus, if you need one supreme, nonmathematical reason, let it be that you joined a project that its creators wanted everyone to be able to participate and help in, independent of how much they could do in any given amount of time.

cheesehead good defending of those old computers!! 15581 gigaflops (copied from primenet at time of posting) 1% of it (if thats what it is) is still 581 gigaflops!! (i think) that is quite a bit of computing power if you ask me!!!