Mersenne Digest Friday, October 15 1999 Volume 01 : Number 644 ---------------------------------------------------------------------- Date: Thu, 14 Oct 1999 21:39:15 -0500 From: Ken Kriesel <[EMAIL PROTECTED]> Subject: Re: Mersenne: # of digits in 2^p-1 Look it up in the FAQ listed at the bottom of every mailing list message, is best in my opinion. Ken At 09:15 PM 1999/10/14 -0400, Darxus wrote: > >What's the best way of finding the number of decimal digits for the number >2^p-1 ? > >__________________________________________________________________ >PGP fingerprint = 03 5B 9B A0 16 33 91 2F A5 77 BC EE 43 71 98 D4 > [EMAIL PROTECTED] / http://www.op.net/~darxus > Join the Great Internet Mersenne Prime Search > http://www.mersenne.org/prime.htm > > >_________________________________________________________________ >Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm >Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers > _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 14 Oct 1999 22:49:17 -0400 From: Jud McCranie <[EMAIL PROTECTED]> Subject: Re: Mersenne: # of digits in 2^p-1 At 09:15 PM 10/14/99 -0400, Darxus wrote: >What's the best way of finding the number of decimal digits for the number >2^p-1 ? p * log10(2) and round up to the next integer. log10(2) = 0.301029996. +---------------------------------------------------------+ | Jud McCranie | | | | Programming Achieved with Structure, Clarity, And Logic | +---------------------------------------------------------+ _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 14 Oct 1999 23:02:01 -0400 (EDT) From: Darxus <[EMAIL PROTECTED]> Subject: Re: estimating primes (was: Re: Mersenne: Islands of Truth) On Thu, 14 Oct 1999, Darxus wrote: > On Thu, 14 Oct 1999, Darxus wrote: > > > On Thu, 14 Oct 1999 [EMAIL PROTECTED] wrote: > > > > > conjectures. <<(#1: That there's a prime around the 4M range that we're > > > missing. #2: That the discovered M38, which all we knew about was that it was > > > in the 6M range, was actually around 6.9M, which I was correct about, and #3: > P digits > #38 5,014,947 1,408,773 > #39 7,414,614 2,070,471 Wow... I recalculated my estimates of P as # of digits * 3.321928094887 -- based on #5.6 from the faq (I really must read that whole thing some time so I stop asking stuff in it....). They came out as: #38 4679842.61 #39 6877955.78 At some point I had a vague recollection that STL had believed there was a number missing, and I was quite happy to see that it basically matched what I got. And rounded, my estimate for #39 equals his. So now I'd estimate we're missing a prime near 2^4679842-1.. but of course when I try to do that manually, I'm getting told it's composite. __________________________________________________________________ PGP fingerprint = 03 5B 9B A0 16 33 91 2F A5 77 BC EE 43 71 98 D4 [EMAIL PROTECTED] / http://www.op.net/~darxus Join the Great Internet Mersenne Prime Search http://www.mersenne.org/prime.htm _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 06:47:18 +0200 From: "Shot" <[EMAIL PROTECTED]> Subject: Mersenne: pre-LL factoring Hi all, I have a simple question: In between of a LL-test I downloaded v19. Soon came the time to request additional work and I got second exponent to stand in the queue. Prime95 switched to factoring the newer one from 63 to 64 - no factor. So far so good - I remember reading somewhere that v19 now factors up to 64 before attempting the LL-test. But then Prime95 switched back to continue the LL-test of the older exponent... The question is: why didn't Prime95 factor the older one from 63 to 64 (I checked - it is factored up to 63)? It would take an additional day, but it could save two weeks that it will take to complete the older one's LL-test... Thanks for your time, - -- Shot __ c"? Shot - [EMAIL PROTECTED] hobbies: Star Wars, Pterry, GIMPS, ASCII `-' [EMAIL PROTECTED] join the GIMPS @ http://www.mersenne.org Science Explained (by Kids): Some oxygen molecules help fires burn while others help make water, so sometimes it's brother against brother. _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 01:18:56 -0400 (EDT) From: Lucas Wiman <[EMAIL PROTECTED]> Subject: Re: estimating primes (was: Re: Mersenne: Islands of Truth) > Hmm... I just changed my worktodo.ini to Test=5014947,63 (where's the 63 > come from ? it was used for the last number I was assigned). > > It's saying "Error: Work-to-do file contained composite exponent: 5014947" > > I suppose that means it's already been tested & found to be non-prime ? > (composite = non-prime, right?) This is for the number of bits the Mersenne number has been trial factored to. I.E. your last number was factored to 2^63. the reason that it reported a problem was that the exponent was composite. This means that the corisponding Mersenne number is composite, thus we only check prime exponents. The number 5014947=3*7*47*5081. Thus 2^3-1, 2^7-1, 2^47-1, and 2^5081-1 all divide 2^5014947-1 (though they do not factor it completely!). - -Lucas _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 00:25:04 -0500 From: Ken Kriesel <[EMAIL PROTECTED]> Subject: Re: Mersenne: Mprime in dual cpu setup? At 06:14 PM 1999/10/14 -0400, "St. Dee" <[EMAIL PROTECTED] wrote: >If I run a single instance of mprime, I get LL iteration times on exponents >near 8,200,000 of about .220. If I run two instances of mprime, each gets >iteration times of around .245. I expected some hit, but I have no idea if >that is too big of a hit or not. Curiously, I did notice that when the box >was doing some factoring to 64 bits, it didn't seem to make any difference >in the factoring times whether I had one or two processors crunching. Sounds like a typical hit. With Prime95 & Prime95 or NTPrime LLtesting, hits are typically Pentium-MMX 18% Pentium Pro 20% Pentium II 10-12% Individual motherboard/cpu combinations can be affected up to 25% by choice of RAM type (at least on pentium, FPM vs EDO) % performance hit is expected to vary with FFT size due to varying cache effectiveness. Ken _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 06:57:23 +0100 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: Islands of Truth On 14 Oct 99, at 9:57, [EMAIL PROTECTED] wrote: > > #4: The Noll Island Theory is not valid. As more > > Mersenne primes are collected, statistical effects > > due to our small sample size will be lessened. > > Actually I think the "theory" is valid, at least in that we'd expect > these sort of clusters - significance testing as you say is pretty > much a lost cause with only 38 data. If it sounds illogical that we have some sort of clustering phenomenon, see Riesel, "Prime Numbers and Computer Methods for Factorization" on super-dense clusters of prime numbers. Sometimes you _can_ get significance from much less than 38 data points. If you toss a coin only 8 times and it falls heads every time, you can be 99% confident that the coin isn't fair. (You would expect a fair coin to deliver a run of 8 matching results once in every 128 trials) > The problem though is it makes no difference where the next one is, > you can always shape the conjecture to fit the existing data. This method is widely used by astrophysicists ;-) > Could anyone pick *one* new Mersenne prime that would either > confirm or deny the island theory? I don't think you can. Just move > the goalposts if you need to. If the theory is that "Mersenne primes occur in pairs" and you define a "pair" as being seperated from their mean by less than 5%, with a gap of at least 50% between the higher of one pair and the lower of the next, then it's already sunk. If it turns out that M6972593 has no "partner" and we find one more in the 5 million range, the statistical evidence (which is, at the moment, tending towards significance) will be badly damaged. Conversely, if the lowest currently undiscovered Mersenne prime turns out to be a partner for M6972593, then the statistical evidence is strengthened. But statistical evidence never _proves_ anything, there's always a chance (even if vanishingly small) that the result could arise accidentally. It's purely a question of whether you want to risk being wrong once in 20 times (5% confidence level), once in 1000 times (0.1% confidence level), or some other figure. But the _real_ problem is that statistics depends on sampling from a population. The sample of Mersenne primes we have at the moment is not only small, it's also _heavily_ biased in favour of the smaller ones. This implies that statistical inferences from our sample _may_ be just as invalid as Gallup's use of telephone polling in the 1936 US Presidential election - in 1936, very few poorer people had telephones. > There's an older version of the Noll Island Conjecture that goes > something like this. You can wait for a bus for hours and hours, > then two come along at once. This was not called the Bus Island > Conjecture - because it's common experience. But there's a straightforward heuristic argument to explain the BIC, which runs something like this. If you have a number of buses spaced equally (in time) on a circular route, the first bus to stop to pick up a passenger will be delayed. Passengers joining the queue "at random" are now more likely to find the delayed bus arrives at their stop, thus delaying it further. The delayed bus also has to stop more frequently to let off passengers who have completed their journey. This delays it more and more, allowing the following bus to catch up. The following bus eventually becomes almost empty ... In order to maintain an even schedule, it's neccessary to build in "holding points" where a bus is artificially delayed to maintain their spacing. If you don't do that, you might as well only have one bus on the route. Apparently this argument is too subtle for urban transport planners, who insist on inflicting us with "banana specials", but that doesn't make it any less true! If there's a similarly convincing heuristic argument as to why Mersenne primes should occur in obvious bunches, I'm sure we'd all like to hear about it. Regards Brian Beesley _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 06:57:23 +0100 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: DOSville On 14 Oct 99, at 17:29, Lucas Wiman wrote: > Sorry, but M$ didn't invent multitasking, and from what I've seen > (I haven't seen NT multitask much) they have yet to implement it effectivly. I'm most definitely _not_ Bill Gates's biggest fan, but I have to say that Windows NT _does_ multi-task pretty well. In fact, in a SMP environment, it's actually rather _more_ effective than linux, you can (but don't have to) force particular threads to run on a given processor. With luck, & provided there aren't _too_ many threads in the "need CPU cycles" queue, this can give you a significant performance boost, since the data you're working on might well be still available in the CPU cache, even if you've been timesliced or interrupted out since you fetched it - whereas pre-fetched data sitting in the cache of another processor is useless to you. I _don't_ understand Win 98 multitasking. I think they got it wrong, Win 95 seems to me to work better. It's possible they were forced into "fixing" it by demands made my multimedia. The specific problem with Win 98 is that a thread running at higher priority is pre-empted by threads running at lower priority far too often - far more often than is needed to be able to respond to mouse clicks, etc. Regards Brian Beesley _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 07:32:25 +0100 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: Mprime in dual cpu setup? On 14 Oct 99, at 18:14, St. Dee wrote: > I'm running mprime (v19) on a dual-processor box (RH 6.0, very basic, no > graphical interface at installed) and am curious about the hit others take > when moving from using one to two processors. (People running duals under > NT are also welcomed to respond!) I'm running two dual systems, both running NT WS 4.0 SP5. One has 2 x PII-350 and one has 2 x PIII-450. > > If I run a single instance of mprime, I get LL iteration times on exponents > near 8,200,000 of about .220. If I run two instances of mprime, each gets > iteration times of around .245. I expected some hit, but I have no idea if > that is too big of a hit or not. Sounds about right. The performance hit gets bigger with bigger clock multipliers. The problem is that having 2 processors accessing 1 memory bus tends to cause memory bus congestion. > Curiously, I did notice that when the box > was doing some factoring to 64 bits, it didn't seem to make any difference > in the factoring times whether I had one or two processors crunching. Yes. Trial factoring will run from the processor cache (even on a Celeron) so doesn't hit the memory bus. Ideally you want to be running something different on the processors of a dual system; a mix of ECM on small exponents & LL testing also works well. > > In case it matters, the box contains 2 Celeron 466 processors on an Abit > BP6 board. Anyone looking for a big speed bump at low cost, try out a > combo like this! I have it on good authority that Intel are trying hard to prevent people constructing dual Celeron systems - because of the potential damage to the PIII market. Be warned, you might buy the bits & it might not work 8-( Regards Brian Beesley _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 08:33:29 +0200 From: Sturle Sunde <[EMAIL PROTECTED]> Subject: Re: Mersenne: DOSville > On 14 Oct 99, at 17:29, Lucas Wiman wrote: > I'm most definitely _not_ Bill Gates's biggest fan, but I have to say > that Windows NT _does_ multi-task pretty well. In fact, in a SMP > environment, it's actually rather _more_ effective than linux, you > can (but don't have to) force particular threads to run on a given > processor. With luck, & provided there aren't _too_ many threads in > the "need CPU cycles" queue, this can give you a significant > performance boost, since the data you're working on might well be > still available in the CPU cache, even if you've been timesliced or > interrupted out since you fetched it - whereas pre-fetched data > sitting in the cache of another processor is useless to you. Linux is smarter -- it automaticaly gives preference for the last CPU used, without any special settings. Sometimes, however, if for some reason the kernel or other threads need that specific CPU, Linux will move the process. You win. Have you noticed what happens when you on Windows NT run one instence of Prime95 on idle priority with affinity to one CPU and start a new CPU-hogging program with normal priority and no processor affinity? The other program will be on the first CPU 50% of the time and on the other CPU the other 50% of the time. 25% of the time one CPU (the one Prime95 isn't using) will be idle, while the other program is using the CPU which Prime95's processor affinity is set to. That's how smart the processor affinity of Windows NT is! I agree that it should be possible to set the automatic "glue" stronger on Linux for certain processes like mprime (without recompiling the kernel) but I think Linux have a much better approach to this than NT. - -- Sturle URL: http://www.stud.ifi.uio.no/~sturles/ Er det m}ndag i dag? ~~~~~~ MMF: http://www.alladvantage.com/go.asp?refid=BUP399 - St. URLe _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 01:03:57 -0800 (AKDT) From: Gordon Bower <[EMAIL PROTECTED]> Subject: Re: Mersenne: types of work to request - 10m digit prime vs. next prime > ------------------------------ > > Date: Thu, 14 Oct 1999 20:44:16 -0400 (EDT) > From: Darxus <[EMAIL PROTECTED]> > Subject: Mersenne: types of work to request - 10m digit prime vs. next prime > > As soon as I heard that there was a $100,000 prize available for finding a > prime, I decided to switch to the 10m digit test, even though my chances > of finding it were extreemly small. I mean, the tiny chance of winning > that cash is better than leaving your idle CPU time idle, right ? > > Unfortunately, this cash prize had clouded my thoughts, as I fortunately > realized when my girlfriend told me she opted not to switch to the 10m > digit tests, because she was more interested in getting her name in the > history books than getting $100,000, and there was is a significantly > greater chance of finding the next prime than there is of finding the 1st > 10m digit prime. I too am more interested in fame than fortune (and incidentally don't put much stock in the Islands) and to this end I've been latching on to smallish exponents. Speaking of fortune - for a few short weeks in April and May, joining GIMPS really was a positive-expectation bet. I could test one exponent in the 4-5M range a week for a 1-in-35000-more-or-less shot at the prize, for roughly $1 electricity per exponent (less than 2 KWH/day at 8c each, with the monitor off when I wasn't at the keyboard). Of course that meant it was more a lottery than research, and it was bound to end within a couple months. [snip] > It was what, half a million dollars total ? I think it would havebeen > much better to award $25k per new prime discovered for the next 20 primes. The purpose of the EFF awards was not to help GIMPS; it was to inspire people to find better ways to find big primes, and, more generally, encourage fresh mathematical thought. Conjecture time: The prime number earning the $150K prize will not be a Mersenne. Why do I say that? Even with processor speeds increasing, we have a good idea how long it'll take to find big primes by Lucas-Lehmer. Even for the 10M-digit prime it'll be a damn long time the way we are doing it now. Finding the monsters requires an intellectual leap by someone - possibly in processor design, more likely in number theory. Admittedly this leap may well be a better version of L-L in which case Mersennes will still be the record primes for a long while to come. But my hunch is that there is a better chance of finding some new way to either construct primes, or to test some other special-form number, than there is of dramatically improving on Lucas-Lehmer. Just a hunch. I might be wrong. I hope I live long enough to see all of the EFF prizes awarded, whether to Mersennes or not. Gordon Bower PS - On an unrelated note --- what is the smallest natural number that is not known whether it is prime or composite? Surely *someone* out there is trying to work from the bottom up and factor every number. (I don't know the answer. I am guessing the it is a smallish number of maybe 15 or so decimal digits?) _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 03:42:10 -0600 From: "Aaron Blosser" <[EMAIL PROTECTED]> Subject: RE: Mersenne: Mprime in dual cpu setup? Alot of the "hit" with multi processors depends on how the system is designed. Especially the memory subsystem since you will go outside the L2 cache alot. I'm still partial to Compaq's design, especially the more obscure things like the ability to split IO requests across more than just one processor...things like that. But the memory subsystem on Proliant servers is a lot better than some I've seen, especially the Dell PowerEdge boxes. When running Prime95 on multiple CPU's on the same machine, the Compaq's see far less a degradation than the PowerEdge boxes, or even IBM's servers (which are actually pretty nice, sad to say). I haven't had a chance to test on any HP SMP boxes, but from my previous experience, the NetServer LX or LS boxes at least don't really do anything special for the memory, so I'd expect a larger "hit". As for the off the shelf dual CPU motherboards, don't expect much. Actually, from what's been reported, the Abit BP6 dual Celeron board doesn't seem to do that bad, considering it's generic quality. I'll be a bit interested to see how Athlon SMP systems fare, how well they scale. Another thing that will be interesting is to see how much improvement Coppermine chips will do with the on-chip cache and with the 133MHz bus speed. Non-cache memory access should be a lot faster especially, with RDRAM's faster speed compared to SDRAM. Otherwise though, it's the same PII core that's been around for ages...don't expect *too* much increases. The new 820 and 840 (whenever those come out) chipsets should make generic dual processor capability a bit better too, I hope. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Michael > Oates > Sent: Thursday, October 14, 1999 5:03 PM > To: [EMAIL PROTECTED] > Subject: Re: Mersenne: Mprime in dual cpu setup? > > > Hi, > > I have a dual PII 560Mhz with NT and get similar results to you, with both > running an exponent M8332549 ish I get times of .220 for each processor, > with just one running it goes to .196 > > Also, if one is doing an LL test and the other factoring the LL test will > run at .196 _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 13:16:21 +0100 From: Michael Oates <[EMAIL PROTECTED]> Subject: Re: Mersenne: problem with prme95 - spl file - ME TOO ! I am also having the same problem, but only on one machine, I have 9 others that are fine, all are using the same version of v19 beta 4 I click on Test | PrimeNet... then tick the box "Send new completion dates to PrimeNet" Click ok, then go to Advanced | Manual Communication and click ok. It connects to the server, updates the information on the server then says Done communicating with the server, just as normal. This computer has not been updated on the primenet server since the 3rd Oct so it's happened a few times and I had not realised till today. I have checked that before I do the Manual Communication to see if the prime.spl was there... it was not ! ???? >Sorry, >Need help having tried to overwrite version 18 with 19-on an LL >test(Win98).Have All the files and managed to run the test from my last save >file pxxxxxxx -Also have q xxxxxxx It initially restarted it.from >scratch...irksome...and downloaded about 10 factorization exponents, when I >just wanted to update and continue..my initial LL test .I have lost (I think >the spl. file )- having been resigned to dragging and dropping files into >the old folder. and deleting old versions... My computer will not update >progress to the primeserver...just keeps sending computer update and user >info...no update on my numerical test..? >Any ideas please?! >Confused...spl files??? how can I create one? >Tel/Fax : +44(0)1904 679906 >Mobile : +44(0)7801 823421 >Website: www.chematekuk.co.uk > >_________________________________________________________________ >Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm >Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers Mike, - -- ATLAS CELESTE - Bevis Star Atlas - & "The CD-ROM" http://www.u-net.com/ph/mas/bevis/ Astronomy in the UK http://www.u-net.com/ph/ _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 07:28:38 -0600 From: "Aaron Blosser" <[EMAIL PROTECTED]> Subject: RE: estimating primes (was: Re: Mersenne: Islands of Truth) > I'd also guess that the skipped prime may have been pretty close to > 2^5014947-1, and have a number of digits close to 1408773. <...> > Hmm... I just changed my worktodo.ini to Test=5014947,63 (where's the 63 > come from ? it was used for the last number I was assigned). > > It's saying "Error: Work-to-do file contained composite exponent: 5014947" > > I suppose that means it's already been tested & found to be non-prime ? > (composite = non-prime, right?) That's because the exponent itself needs to be prime, and 5014947 is not. Divides by 3 in fact. _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 09:46:40 -0400 From: George Woltman <[EMAIL PROTECTED]> Subject: Re: Mersenne: pre-LL factoring Hi, At 06:47 AM 10/15/99 +0200, Shot wrote: >The question is: why didn't Prime95 factor the older one from 63 to >64? No good reason. The program doesn't do any trial factoring once an LL test has begun. Regards, George _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 16:27:21 +0200 (CEST) From: Henrik Olsen <[EMAIL PROTECTED]> Subject: Re: Mersenne: problem with prme95 - spl file - ME TOO ! On Fri, 15 Oct 1999, Michael Oates wrote: > I have checked that before I do the Manual Communication to see if the > prime.spl was there... it was not ! prime.spl only ever exists when there is something to send to the server and it hasn't been sent yet. If it's not present, there is no communication spooled. - -- Henrik Olsen, Dawn Solutions I/S URL=http://www.iaeste.dk/~henrik/ Thomas Daggert to Lucifer: I have my soul, and I have my faith. What do you have... angel? The Prophecy _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 08:09:31 -0700 From: "John R Pierce" <[EMAIL PROTECTED]> Subject: Re: Mersenne: DOSville > Linux is smarter -- it automaticaly gives preference for the last CPU > used, without any special settings. Sometimes, however, if for some > reason the kernel or other threads need that specific CPU, Linux will > move the process. You win. Actually, NT does the same thing. > Have you noticed what happens when you on Windows NT run one instence > of Prime95 on idle priority with affinity to one CPU and start a new > CPU-hogging program with normal priority and no processor affinity? > The other program will be on the first CPU 50% of the time and on the > other CPU the other 50% of the time. 25% of the time one CPU (the one > Prime95 isn't using) will be idle, while the other program is using > the CPU which Prime95's processor affinity is set to. That's how smart > the processor affinity of Windows NT is! have you actually tested this? That doesn't sound right to me, the idle processor should get the next avaiable process regardless. Sure, I could see the CPU with the affinity getting some slices from the other process, but NT is not going to leave a CPU 50% idle with ready processes. - -jrp _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 17:45:25 +0200 From: Sturle Sunde <[EMAIL PROTECTED]> Subject: Re: Mersenne: DOSville >> Linux is smarter -- it automaticaly gives preference for the last CPU >> used, without any special settings. Sometimes, however, if for some >> reason the kernel or other threads need that specific CPU, Linux will >> move the process. You win. > Actually, NT does the same thing. Nope. You set the affinity to CPU 0, 1, etc. The process will then _only_ run on that specific CPU. >>... > have you actually tested this? Start Prime95 at idle priority with CPU affinity set to one of the CPUs. Start the "Tast Manager", choose "Performance" and look at the graphs. One should be at 100%, the other close to 0%. Then start another process at normal priority and see how the load of that process divides between the CPUs, leaving one 50% idle while Prime95 stays on the single CPU it has set affinity to (the other). I tried this on a Windows NT 4.00.1381 Service Pack 3 Terminal Server. - -- Sturle URL: http://www.stud.ifi.uio.no/~sturles/ Er det m}ndag i dag? ~~~~~~ - St. URLe _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 16:47:03 +0100 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: problem with prme95 - spl file - ME TOO ! On 15 Oct 99, at 13:16, Michael Oates wrote: > I am also having the same problem, but only on one machine, I have 9 others > that are fine, all are using the same version of v19 beta 4 What's different? Must be _something_ ... > > I click on Test | PrimeNet... then tick the box "Send new completion dates > to PrimeNet" Click ok, then go to Advanced | Manual Communication and click > ok. It connects to the server, updates the information on the server then > says Done communicating with the server, just as normal. > > This computer has not been updated on the primenet server since the 3rd Oct > so it's happened a few times and I had not realised till today. > > I have checked that before I do the Manual Communication to see if the > prime.spl was there... it was not ! I thought this behaviour was normal since about V19 beta 2, when I queried it I was told it had been modified as a result of a request from Scott Kurowski to update the computer information every time the client contacts PrimeNet, for whatever reason. Even if you force a connection without there being a need to communicate results or update completion dates. There will not be a prime.spl file in this case (nor if the system realises during a forced connection that it would like to fetch another assignment from the server). > >Confused...spl files??? how can I create one? Select "Send new completion dates" in the Test/Primenet menu. Or simply wait for an assignment to finish, or long enough for the system to want to update the completion dates automatically (Options/Preferences/Days between, default 28 days) Regards Brian Beesley _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 16:01:56 GMT From: [EMAIL PROTECTED] (Michael Oates) Subject: Re: Mersenne: problem with prme95 - spl file - ME TOO ! Hi, >Why don't you get the release version of v19? Well that is of course what I will do when I get back to work. But I thought it very strange that only one machine was behaving in this way. >----- Original Message ----- >From: Michael Oates <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Sent: Friday, October 15, 1999 2:16 PM >Subject: Re: Mersenne: problem with prme95 - spl file - ME TOO ! > > >> I am also having the same problem, but only on one machine, I have 9 >others >> that are fine, all are using the same version of v19 beta 4 >> >> I click on Test | PrimeNet... then tick the box "Send new completion dates >> to PrimeNet" Click ok, then go to Advanced | Manual Communication and >click >> ok. It connects to the server, updates the information on the server then >> says Done communicating with the server, just as normal. >> >> This computer has not been updated on the primenet server since the 3rd >Oct >> so it's happened a few times and I had not realised till today. >> >> I have checked that before I do the Manual Communication to see if the >> prime.spl was there... it was not ! >> >> ???? >> > > Mike, - -- ATLAS CELESTE - Bevis Star Atlas - & "The CD-ROM" A very rare atlas found at the Godlee Observatory http://www.u-net.com/ph/mas/bevis/ Astronomy in the UK http://www.ph.u-net.com _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 16:01:57 GMT From: [EMAIL PROTECTED] (Michael Oates) Subject: Re: Mersenne: problem with prme95 - spl file - ME TOO ! Henrik, Ah, but, it should be spooled because I have asked it send new completion dates to PrimeNet. It does it on my other machines. I will put the final version of v19 on and see if that works. >On Fri, 15 Oct 1999, Michael Oates wrote: >> I have checked that before I do the Manual Communication to see if the >> prime.spl was there... it was not ! >prime.spl only ever exists when there is something to send to the server >and it hasn't been sent yet. > >If it's not present, there is no communication spooled. Mike, - -- ATLAS CELESTE - Bevis Star Atlas - & "The CD-ROM" A very rare atlas found at the Godlee Observatory http://www.u-net.com/ph/mas/bevis/ Astronomy in the UK http://www.ph.u-net.com _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 18:25:42 +0100 (BST) From: Chris Jefferson <[EMAIL PROTECTED]> Subject: Mersenne: Modular arthimatic.. Hi! Just something I was pondering a couple of days ago... Consider a general number (odd) number c which can be factored into ab=c W.L.O.G. assume b is greater than a then let x=(a+b)/2 , y=(b-a)/2 then (x+y)(x-y)=c x^2 - y^2 = c x^2 = c + y^2 So if we can find if this equation has any integer solutions, we've found our factors... Ways of doing this: The difference of two squares is always an arthimetic progression of odd numbers. Here is an example.. 2^2 - 1^2 = 3 3^2 - 2^2 = 5 4^2 - 3^2 = 7 and so on... So look at general sum of an arthimetic series S(n) = (n/2)(2a + (n-1)d) In this case d=2 and a is odd, so need to try to solve c = na + n(n-1)/2 for integers n,a Also, try to solve x^2 - y^2 = 0 mod c As if this is solvable, then (x-y)(x+y)=nc, for integer n, so must be able to cancel out all factors of n in either (x-y) or (x+y) to get back to a solution of equation.. Alternativly, could try to find out by some kind of set notation what the size of the group of solns. is... This is where I come unstuck. I believe this is an example of an eliptic curve, and I want the c'th term in it's L-series. Could we transform it into a modular form and then quickly work out this term. I could well be in cloud-cockoo land now, as I aren't even totally sure what a modular form is, but I know that the L-series of modular forms, and some series related to modular forms are the same, and this proof lead the the solution of Fermat's Last Thereom.... Anyway, if anyone could just vaguely point me in the right direction, or tell me if I am talking rubbish before I go and start reading up on all this... Thanks! - ------------------------------------ Chris Jefferson, Girton College, Cambridge, [EMAIL PROTECTED] - ------------------------------------ Someone may have beaten me to Fermat's Last Theorem, but I've done Riemann's general equation. However it won't fit in my signature file... - ------------------------------------ _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 15 Oct 1999 14:16:17 -0400 From: Jud McCranie <[EMAIL PROTECTED]> Subject: Re: Mersenne: Modular arthimatic.. At 06:25 PM 10/15/99 +0100, Chris Jefferson wrote: Consider a general number (odd) number c which can be factored into ab=c >W.L.O.G. assume b is greater than a > >then let x=(a+b)/2 , y=(b-a)/2 > >then (x+y)(x-y)=c > >x^2 - y^2 = c > >x^2 = c + y^2 > >So if we can find if this equation has any integer solutions, we've found >our factors... Good idea, but this is Fermat's factoring method. It works pretty well if a and b are close. +---------------------------------------------------------+ | Jud McCranie | | | | Programming Achieved with Structure, Clarity, And Logic | +---------------------------------------------------------+ _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ End of Mersenne Digest V1 #644 ******************************
