Mersenne: Re: Timing(?) errors
On Mon, Sep 20, 1999 at 05:45:17PM -0500, Willmore, David wrote: Since it's a cache reading problem there's no real way to 'flush' it. Normally, that means to write back dirty data to whatever backing store exists, not 'invalidate everything'. Even if you did, it would't solve the problem. How does swap space come into this? Linux isn't forced to swap the data in exactly where it used to be, is it? [removed excellent explanation on what's going on] Thanks. :-) Yes, it would probably be easier in Linux, but it might not do you any good. Perhaps I could do a manual restart if it was a problem? (I can thing of several crazy ways to do this... Perhaps fill the all the buffers with some random number, and find them in /proc/kcore? ;-) ) /* Steinar */ -- Homepage: http://members.xoom.com/sneeze/ _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Iteration Times (was: GIMPS client output)
Wouldn't the run time at 4.231 be about 10 years? --- Eric Hahn [EMAIL PROTECTED] wrote: Okay, okay... obviously a lot of people were awake sigh (you can stop flooding me with emails!!) In a previous message I wrote: P.S. At the 79.3M range, you'll probably not want to set it at 100 iterations... Per iteration time on 266MHz PII with 64MB RAM is 58.781 seconds!!! (Yes, it's true, but I'm also just checking to see if anybody's awake :)) I went back to the exponent in question and ran another test. There are a couple of notes here: 1) This originally was done for a particular test in QA. 2) George didn't have the new timings up at the time. 3) I thought it was high myself, but what did I know? What I found was: 1) I obviously had something running in the background I was not aware of. 2) The actual time dropped to 4.231 sec/iter 3) Amazingly, there didn't appear to be much HDD paging happening except went you hit 'STOP'! BTW, for those of you who don't know (or actually asked), these exponents use 4096K FFT runlengths, and 16M save files... Eric Hahn _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers __ Do You Yahoo!? Bid and sell for free at http://auctions.yahoo.com _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
RE: Mersenne: Re: Timing(?) errors
On Mon, Sep 20, 1999 at 05:45:17PM -0500, Willmore, David wrote: Since it's a cache reading problem there's no real way to 'flush' it. Normally, that means to write back dirty data to whatever backing store exists, not 'invalidate everything'. Even if you did, it would't solve the problem. How does swap space come into this? Linux isn't forced to swap the data in exactly where it used to be, is it? Correct, it does not. Normally, though, when you're swapping, proper L2 cache coloring is the least of your performance problems. Yes, it would probably be easier in Linux, but it might not do you any good. Perhaps I could do a manual restart if it was a problem? (I can thing of several crazy ways to do this... Perhaps fill the all the buffers with some random number, and find them in /proc/kcore? ;-) ) A syscall that walked the page tables to find the translation for an address would probably the easiest. Cheers, David _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: FDIV Pentium error
I was wondering if Prime95 is affected by the Pentium FDIV bug. (or some name like that). I ask this because now i'm also using it on my laptop (great work george!) and when i installed linux some time ago it said the processor had this bug. Floris Looyesteyn _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: FDIV Pentium error
I was wondering if Prime95 is affected by the Pentium FDIV bug. (or some name like that). I ask this because now i'm also using it on my laptop (great work george!) and when i installed linux some time ago it said the processor had this bug. It should not be a problem because Linux recognizes the bug and uses a workaround. Regards /Lars _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Re: Re: Timing(?) errors
On Tue, Sep 21, 1999 at 02:03:54PM -0500, Willmore, David wrote: Correct, it does not. Normally, though, when you're swapping, proper L2 cache coloring is the least of your performance problems. Yes, but if you _force_ swap-out-swap-in, like ReCache does? /* Steinar */ -- Homepage: http://members.xoom.com/sneeze/ _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Re: FDIV Pentium error
On Tue, Sep 21, 1999 at 09:25:02PM +0200, Floris Looyesteyn wrote: I was wondering if Prime95 is affected by the Pentium FDIV bug. (or some name like that). I've run it with on a P60 (with the FDIV bug) for 2-3 years now (at least pre-PrimeNet), and it has never been a problem. Remember that the bug influences FDIV only (which is very slow -- and thus George doesn't use it that much ;-) ), and not to a very great extent either. /* Steinar */ -- Homepage: http://members.xoom.com/sneeze/ _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
RE: Mersenne: Re: Re: Timing(?) errors
Random chance. I wouldn't count on it. -Original Message- From: Steinar H. Gunderson [SMTP:[EMAIL PROTECTED]] Sent: Tuesday, September 21, 1999 4:12 PM To: [EMAIL PROTECTED] Subject: Mersenne: Re: Re: Timing(?) errors On Tue, Sep 21, 1999 at 02:03:54PM -0500, Willmore, David wrote: Correct, it does not. Normally, though, when you're swapping, proper L2 cache coloring is the least of your performance problems. Yes, but if you _force_ swap-out-swap-in, like ReCache does? /* Steinar */ -- Homepage: http://members.xoom.com/sneeze/ _ 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
Re: Mersenne: Prime95 v19 oops...
Hi, At 10:09 PM 9/20/99 +0300, Jukka Santala wrote: Something I forgot from earlier playing, the manual factoring savefiles on Prime95 v19 at least don't work out too well especially on dual-CPU machines... Since these savefiles will always be named "p000" regardless of the -A parameter and exponent to test ;) This is a v18 bug that I declined to fix. Maybe I should delete that Advanced/Factor menu choice :) To work around this create one directory for each CPU. This is the only known flaw in dual-CPU environments. Regards, George _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Factoring
Does anybody know if there is an exponent where the factor is, or know whether there is a proof on whether a factor can (or can't) be, a root?? A square?? To clarify this: We know that any factor of 2^p-1 is in the form 2kp+1. Letting x =2, Can (2kp+1)^x = 2^p-1 ?? Can (2kp+1)^x * (2kp+1) ... = 2^p-1 ?? Eric Hahn _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: v19 manual workdodo.ini error.
Hi, At 02:42 PM 9/18/99 +0200, Lars Lindley wrote: I discovered a lost exponent in the team-report and thought I would reassign that exponent for myself. I manually edited the worktodo.ini by adding the row DoubleCheck=3393469,61 on the first line. I thought that prime95 would put the exponent I was working on on hold to do the doublecheck first as v18.1 would have. To my surprise it continued with the old exponent. I've tracked down and fixed this bug that Lars and Rick reported. Look for a new v19 beta in the next day or two (I'll announce it to the mailing list). Regards, George _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne Digest V1 #629
Mersenne Digest Tuesday, September 21 1999 Volume 01 : Number 629 -- Date: Sun, 19 Sep 1999 21:36:01 -0400 From: Jeff Woods [EMAIL PROTECTED] Subject: Re: Mersenne: M(M(127)) and other M(M(p)) At 08:51 PM 9/19/99 -0400, you wrote: prime, unless we find a factor. Interestingly enough, when we find the next Mersenne prime, searching for a factor of M(M(p)) might allow us to find an even bigger prime. If for example, 6*M(p)+1 divides M(M(p)), then it must be prime! Which one must be prime? 6*M(p)+1, or M(M(p))? And why? Enquiring minds, and all Thanks! Wait, that might just be the reason to search! Will only searched up to k=4 for M(M(6972593)), but if 2*k*M(p)+1 divides M(M(p)), then you've just beaten the world record! Non-Mersenne's might once again grace the top 10 list! An interesting concept -- what sort of time factor would it take to prove such a thing with an average computer? _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers -- Date: Sun, 19 Sep 1999 21:33:53 -0400 From: "Chris Nash" [EMAIL PROTECTED] Subject: Re: Mersenne: M(M(127)) and other M(M(p)) even bigger prime. If for example, 6*M(p)+1 divides M(M(p)), then it must be prime! Before anybody gets overexcited at the last posting... It is TRUE that if 2k.M(p)+1 divides M(M(p)), M(p) is prime, and k2M(p)+2, then 2k.M(p)+1 is prime. However, unless I'm mistaken, non-divisibility does not prove compositeness. You could walk past a prime (in fact, you'd expect to walk past several) and you'd never know... Chris _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers -- Date: Sun, 19 Sep 1999 22:27:59 -0400 (EDT) From: Darxus [EMAIL PROTECTED] Subject: Mersenne: GIMPS client output Iteration: 164000 / 8410531 [1%]. Clocks: 115665753 = 0.496 sec. Might be nice to display the percentage out to an accuracy that changes every hundred iterations. Hmm, looks like that's an integer of the percentage, not rounded. Guess it doesn't matter. For the one I'm working on it looks like 3 decimal places would be needed to see a change every 100 iterations. __ 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: Sun, 19 Sep 1999 22:59:37 -0400 From: "Rick Pali" [EMAIL PROTECTED] Subject: RE: Mersenne: GIMPS client output From: Darxus Iteration: 164000 / 8410531 [1%]. Clocks: 115665753 = 0.496 sec. Might be nice to display the percentage out to an accuracy that changes every hundred iterations. If you're using version 19, add "PercentPrecision=3" to the prime.ini file. If you want more than three decimal places, change the number...I believe it'll go up to six. I believe that four should be sufficient as even M33219281 changes every three or four hundred iterations with three places displayed. Rick. - -+--- [EMAIL PROTECTED] http://www.alienshore.com/ _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers -- Date: Sun, 19 Sep 1999 23:05:39 -0400 (EDT) From: Lucas Wiman [EMAIL PROTECTED] Subject: Re: Mersenne: GIMPS client output Might be nice to display the percentage out to an accuracy that changes every hundred iterations. Hmm, looks like that's an integer of the percentage, not rounded. Guess it doesn't matter. For the one I'm working on it looks like 3 decimal places would be needed to see a change every 100 iterations. This is changed in V19 (currently in Beta). I believe (George correct me if I'm wrong) that you can specify it up to 6 decimal places. - -Lucas _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers -- Date: Sun, 19 Sep 1999 23:24:41 -0400 From: "Chris Nash" [EMAIL PROTECTED] Subject: Re: Mersenne: M(M(127)) and other M(M(p)) Hi Jeff prime, unless we find a factor. Interestingly enough, when we find the next Mersenne prime, searching for a factor of
Re: Mersenne: Factoring
At 04:27 PM 9/21/99 -0700, Eric Hahn wrote: We know that any factor of 2^p-1 is in the form 2kp+1. Letting x =2, Can (2kp+1)^x = 2^p-1 ?? Can (2kp+1)^x * (2kp+1) ... = 2^p-1 ?? No known factors of Mersenne numbers have x1, but it hasn't been proven that it is impossible. +-+ | 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
Re: Mersenne: Iteration Times (was: GIMPS client output)
At 09:47 AM 9/21/1999 -0700, James Escamilla wrote: Wouldn't the run time at 4.231 be about 10 years? Yes, for that particular exponent (79,299,959), it would take approx. 10 yrs. and 231 days to test. That's assuming 4 items: 1) A P2 266MHz PC was being used the entire time. 2) The PC was being used exclusively to test the exponent 24/7. 3) The 4.231 sec/iter is constant (which it isn't!) 4) A factor isn't found (below 2^62 is unsuccessful at least!) Eric Hahn _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: FDIV Pentium error
All programs are affected by the FDIV bug. It is a bug in the design of the microprocessor. Linus has a way around it. The brain dead morons at Microsoft have to make everyone else wait for a solution (That has yet to come AFIK). Linux on the other hand usually has problems solved in a matter of hours. -Chuck On Tue, 21 Sep 1999, Floris Looyesteyn wrote: I was wondering if Prime95 is affected by the Pentium FDIV bug. (or some name like that). I ask this because now i'm also using it on my laptop (great work george!) and when i installed linux some time ago it said the processor had this bug. Floris Looyesteyn _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers -- ~~~ : WWW: http://www.silverlink.net/poke : : E-Mail: [EMAIL PROTECTED] : ~~ : Ask Mike! Aviation's response to Dear : : Abby. http://www.avstarair.com: ~~~ _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: M(M(127)) and other M(M(p))
Hi folks Wait, that might just be the reason to search! Will only searched up to k=4 for M(M(6972593)), but if 2*k*M(p)+1 divides M(M(p)), then you've just beaten the world record! Non-Mersenne's might once again grace the top 10 list! I really hope that neither Will Edgington (with M(M(6972593))) nor Chip Kerchner (with M(M(1398269))) dedicated any computer time whatsoever to search for factors 2*k*M(p)+1 up to k=4. As Will's page http://www.garlic.com/~wedgingt/MMPstats.txt points out, since M(p)=1 mod 3, k cannot be 1 mod 3. Also, since M(p)=-1 mod 8 for odd p=3, k must be 0 or 1 mod 4 (otherwise 2 is not a quadratic residue of this supposed factor, the 8x+-1 condition). It follows then the first possible factor of M(M(p)) has k=5. Chris Nash Lexington KY UNITED STATES _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
