Mersenne Digest Friday, September 3 1999 Volume 01 : Number 621 ---------------------------------------------------------------------- Date: Wed, 01 Sep 1999 09:27:39 -0400 From: Yvan Dutil <[EMAIL PROTECTED]> Subject: Mersenne: New Goal? It is very likely that we will succed to reach the Y2K goal. Maybe it is time now to set a new one? I stick with the suggestion I made a few months ago: 10 000 000 before the new millenium? What do you think? Yvan Dutil _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 01 Sep 1999 10:49:07 -0400 From: Jeff Woods <[EMAIL PROTECTED]> Subject: Re: Mersenne: New Goal? At 09:27 AM 9/1/99 -0400, you wrote: >It is very likely that we will succed to reach the Y2K goal. Maybe it is >time now to set a new one? I stick with the suggestion I made a few months >ago: 10 000 000 before the new millenium? > >What do you think? I think we'll now endlessly debate whether the millennium begins at 12:00:01 on January 1st, 2000, or one year later than that. ;-) With roughly 71 CPU years a day, and linear growth to about 101 CPU years a day in 16 months (a SWAG), that's an average of 86 years per day, or 486.6 days. That's 41,800 CPU years between now and the first day of 2001. With only 14,944 years to go to clear those exponents less than 10.3MM, I'd say you stand a fair chance of succeeding, even though the inevitable last minute stragglers will take much longer than expected. (No, not the poaching thread again!). We stand a fair shake at getting those less than 11MM cleared. Now, if you thought that the Millennium begins on the first day of 2,000, well, then we'll only get about 8750 CPU years done between now and then, and will not likely have cleared all of those exponents. Have I re-opened enough old wounds (poaching, when is the millennium), or should I talk about overclocking and Island theory now? ;-) _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 01 Sep 1999 17:17:23 +0200 From: Dennis =?iso-8859-1?Q?J=F8rgensen?= <[EMAIL PROTECTED]> Subject: Mersenne: Several "illegal sumout" Hi list I've been running Prime95 for a while now (close to finishing my third LL test). My problem is that in the first 2 tests I've had one illegal sumout error in each (both exponents were around 7.6-7.7 million). As the readme text said this probably didn't mean anything I didn't do anything about it. But in the test I'm running now I've had 4 of these errors (exponent just over 8 million). This seems a bit too much to me, am I right? I've noticed that they happen as the computer starts. One of the times I figured that something might had gone wrong in the startup, so I restarted the computer, just to get another one. With the 2 last errors I've also noticed that the tray icon appears later when the errors happen, it normally appears before my virusscanner and a few other things, it comes up almost last when errors happen. Anyone with an idea why this is happening? by the way, my computer is a Celeron-400 (not overclocked) with 64Mb of ram, it gets 0.314 sec/interation on the exponent I'm running now, is this about right? I've looked at the page with timings, but they appear only to be with smaller exponents, where I get less than half the time of a PII-400, which seems strange, am I reading the data wrong, or am I wrong in comparing to a PII-400 when it's small exponents? regards Dennis J�rgensen _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 01 Sep 1999 12:00:43 -0400 From: Yvan Dutil <[EMAIL PROTECTED]> Subject: Re: Mersenne: New Goal? At 10:49 AM 9/1/99 -0400, Jeff Woods wrote: >At 09:27 AM 9/1/99 -0400, you wrote: > >>It is very likely that we will succed to reach the Y2K goal. Maybe it is >>time now to set a new one? I stick with the suggestion I made a few months >>ago: 10 000 000 before the new millenium? >With roughly 71 CPU years a day, and linear growth to about 101 CPU years a >day in 16 months (a SWAG), that's an average of 86 years per day, or 486.6 >days. That's 41,800 CPU years between now and the first day of 2001. > >With only 14,944 years to go to clear those exponents less than 10.3MM, I'd >say you stand a fair chance of succeeding, even though the inevitable last >minute stragglers will take much longer than expected. (No, not the >poaching thread again!). We stand a fair shake at getting those less than >11MM cleared. You are probably right. I didn't think we could could acheived easily a jump of 5 millions in one year. Also, in the calculation you have to take acount that about 1/3 of the CPU is devoted to double-checking. Overall, 10 millions looks a fairly honest goal for January 1 2001. Yvan Dutil _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 01 Sep 1999 17:40:03 -0400 From: George Woltman <[EMAIL PROTECTED]> Subject: Re: Mersenne: Several "illegal sumout" Hi, At 05:17 PM 9/1/99 +0200, Dennis J�rgensen wrote: >But in the test I'm running now I've had 4 of these errors >(exponent just over 8 million). This seems a bit too much to me, am I >right? Your result is likely OK. Prime95 recovers well from this error and it not usually an indicator that undetected errors are corrupting the results. The readme.txt file gives some ideas as to what the causes might be. >I've noticed that they happen as the computer starts. This is new. The usual cause is a device driver playing a MIDI file. Probably a driver did not save the CPU state properly while initializing. >With the 2 last errors I've also noticed that the tray icon appears >later when the errors happen, Not unexpected. Prime95 sleeps for 5 minutes after a SUMOUT error. >Celeron-400 gets 0.314 sec/interation on the exponent I'm running now, Seems right. Compare it to the PII-400 timings on http://www.mersenne.org/status.htm Remember that the timings on that page are for version 19 which is up to 10% faster than version 18. Regards, George _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 02 Sep 1999 00:52:44 +0200 From: Johan Winge <[EMAIL PROTECTED]> Subject: Re: Mersenne: Several "illegal sumout" At 17:17 1999-09-01 +0200, Dennis J�rgensen wrote: > >My problem is that in the first 2 tests I've had one illegal sumout >error in each (both exponents were around 7.6-7.7 million). As the >readme text said this probably didn't mean anything I didn't do anything >about it. But in the test I'm running now I've had 4 of these errors >(exponent just over 8 million). This seems a bit too much to me, am I >right? I don't think you should worry. It often happens, that after my younger brother have played some games on my (family's) fastest machine (a PII-233) I can immediately tell he have done so, because when I connect to Internet Prime95 reports a bunch of "illegal sumout", around 20 at the extreme, though usually only one or two. I hate when it happens, but as far as I know it haven't done any harm to my results. By the way, is anyone interested in a copy of p6972593 at the 6900000th iteration? I wasted a whole month during the summer to check it, and yes, it turned out to be prime, regardless of all the "illegal sumout"s the occured during the process! Regards, Johan Winge _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 01 Sep 1999 22:05:05 -0700 From: Spike Jones <[EMAIL PROTECTED]> Subject: Mersenne: too hot? too cold? perfect? With every Mersenne number there is an associated perfect number, the sum of whose factors exactly equal the number. I discovered a fascinating thing today, for which I must introduce some new terminology. If a number is greater than the sum of its factors, let it be a cold number. If a number is less than the sum of its factors, let it be a hot number. Odd numbers are all cold, for instance, and the first hot number is 12. Nowthen, I found that the ratio of cold numbers to hot numbers is always about 3. Even when you get up to large numbers [I checked them all up to about 100,000] the ratio seems to stay right around 3 colds to every hot. Is there an embarrassingly trivial reason for this? Is there established terminology for hot and cold numbers? spike _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 01 Sep 1999 23:44:53 -0700 From: Spike Jones <[EMAIL PROTECTED]> Subject: Re: Mersenne: too hot? too cold? perfect? The program is OK, I just overlooked the fact that there are in fact odd abundant numbers. doh! spike _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 2 Sep 1999 03:54:06 -0500 (CDT) From: Conrad Curry <[EMAIL PROTECTED]> Subject: Re: Mersenne: too hot? too cold? perfect? On Wed, 1 Sep 1999, Spike Jones wrote: > With every Mersenne number there is an associated perfect > number, the sum of whose factors exactly equal the number. A number is perfect iff the sum of the positive divisors, including one and excluding the number itself, is equal to the number. > I discovered a fascinating thing today, for which I must introduce > some new terminology. > > If a number is greater than the sum of its factors, let it be a cold number. > If a number is less than the sum of its factors, let it be a hot number. If s(n) is the sum of the positive divisors of n including one then a perfect number has s(n) = 2n. From Chapter XIV of Nicomachus If s(n) > 2n then n is abundant and for s(n) < 2n then n is deficient. > Odd numbers are all cold, for instance, and the first hot number is 12. 945 is odd and abundant. > Nowthen, I found that the ratio of cold numbers to hot numbers is > always about 3. Even when you get up to large numbers [I checked > them all up to about 100,000] the ratio seems to stay right around > 3 colds to every hot. This is known. See, for example, Deleglise, M. ``Bounds for the Density of Abundant Integers.'' Exp. Math. 7, 137-143, 1998 at http://www.expmath.org/restricted/7/7.2/deleglise.ps.gz He gives the result 0.2474 < A(2) < 0.2480 where A(2) is the density of abundant numbers (he includes perfect numbers as abundant). _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 2 Sep 1999 12:03:58 +0200 (MET DST) From: Reto Keiser <[EMAIL PROTECTED]> Subject: Mersenne: Suggestions for Prime95 v19 Hi all, Now before the new version of Prime95 is released I have some suggestions for new function which should not be too difficult to add: - - A menu item that forces the program to write intermediate data to disk. It is useful, when the user wants to install a new program or play a game which probably forces the computer to crash. So it is possible to save data without exiting the program before a riskful action. - - A function which prvents writing to disk for some time. When the user writes a CDr, it sometimes is dangerous, when prime95 writes intermediate results to disk during that time. - - Extended status information -relative speed of the system (e.g. using rolling average) -hours in use -# flops done (calculated) -# iterations done (total of all exponents) -history: all tested iterations on this machine -processor usage (compared with the unused system Maybe George Woltman can implement some of these functions, so that the use better knows what the program does. Cheers Reto _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 02 Sep 1999 14:30:01 GMT From: [EMAIL PROTECTED] (Foghorn Leghorn) Subject: Re: Mersenne: Suggestions for Prime95 v19 >- A menu item that forces the program to write intermediate data to > disk. It is useful, when the user wants to install a new program or Doesn't stopping work with the escape key or Test/Stop already do this? You could simply stop and restart work in order to commit results to the disk. >- A function which prvents writing to disk for some time. When the user > writes a CDr, it sometimes is dangerous, when prime95 writes > intermediate results to disk during that time. If this is a problem on your system, then you could increase the interval between disk writes to some large value, and then stop and restart work as above to commit results. I've burned three CD-R discs at quad speed with my new drive recently, and I haven't had any problems. It is nice not to have to stop Prime95 for this. Of course this will depend on how well your computer keeps up with the stream of data required by the CD-R drive. On a slower computer, a disk write from Prime95 could theoretically cause a buffer underrun. The best way to find out is with a test burn. I doubt that Prime95 will cause many problems in this regard. > >- Extended status information > -relative speed of the system (e.g. using rolling average) > -hours in use > -# flops done (calculated) > -# iterations done (total of all exponents) > -history: all tested iterations on this machine > -processor usage (compared with the unused system This sounds a little more involved (from a programming standpoint) that it is worth. But I could be wrong. Foghorn Leghorn [EMAIL PROTECTED] _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 1 Sep 1999 22:38:58 +0200 From: "Steinar H. Gunderson" <[EMAIL PROTECTED]> Subject: Mersenne: Re: Re: How about some C code? On Sun, Aug 29, 1999 at 12:03:19AM -0400, Gord Palameta wrote: >That would produce a version that compiles and executes the same as the >Fortran original, but presumably more slowly because of aliasing in C >preventing some compiler optimizations that Fortran can do. I've got exactly 0 minutes and 0 seconds experience with Fortran, but can't you just specify `-fargument-noalias-global' (to gcc), use `const', `restrict' (supposed to be a part of ISO C 9X, but I don't know anything more about it) or some other fancy keyword? /* 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 ------------------------------ Date: Thu, 02 Sep 1999 09:23:30 -0700 From: Eric Hahn <[EMAIL PROTECTED]> Subject: RE: Mersenne: Suggestions for Prime95 v19 ::Reto Keiser <[EMAIL PROTECTED]> wrote: >Now before the new version of Prime95 is released I have >some suggestions for new function which should not be too >difficult to add: Some of these functions exist already in v18 and prior versions, just not as you might think... >- A menu item that forces the program to write > intermediate data to disk. It is useful, when the user > wants to install a new program or play a game which > probably forces the computer to crash. So it is > possible to save data without exiting the program > before a riskful action. Prime95 already does this if you use the menu items TEST | STOP and then TEST | CONTINUE. >- A function which prvents writing to disk for some > time. When the user writes a CDr, it sometimes is > dangerous, when prime95 writes intermediate results > to disk during that time. Again, you can either use the procedure above to stop Prime95 before and start it after CD-R recording, or you can change the minutes between disk writes under OPTIONS | PREFERENCES before beginning recording. >- Extended status information > -relative speed of the system (e.g. using rolling average) > -hours in use Not sure what you're looking for here... Possibly, the same information Prime95 uses to calculate ECD (estimated completion dates)?? > -# flops done (calculated) Hmmm... This seems like it might be a little difficult. First, Prime95 uses integer code on 486, Cyrix, and AMD K5 chips when performing factoring. Second, each iteration of a test involves many calculations. Third, Prime95 is running as a background (idle process) task. > -# iterations done (total of all exponents) > -history: all tested iterations on this machine Take a look at the RESULTS.TXT file in the directory with Prime95. It lists the results from all previous exponents... > -processor usage (compared with the unused system Running as a background (idle process) task makes this unfeasible. You'd be better off using something like WinTop in Windows95 (found in the Win95 KernelToys) or something like it for other OSes... Eric Hahn _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 2 Sep 1999 13:16:43 -0400 From: "Rick Pali" <[EMAIL PROTECTED]> Subject: Mersenne: GIMPS totals. I understand that the differences between the GIMPS and the Primenet standings are an artefact of how GIMPS was up and running before Primenet. Consequently, anyone that joined and finished numbers before Primenet was running will have different totals on each list. My question is whether this logic has changed at all. The August 16th GIMPS update shows me with 13.39 years and 125 exponents tested and I was surprised to see that Tuesday's update shows 12.58 years and 127 exponents! Perhaps this question should be for George, but I thought that maybe I missed a message about a change or something. Any comment is welcome. 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: Tue, 31 Aug 1999 13:11:38 -0500 From: "Robert G. Wilson v" <[EMAIL PROTECTED]> Subject: Re: Mersenne: too hot? too cold? perfect? Dear Spike, In keeping with the Three bears, the perfect numbers would be "just right." The proper terminology to apply to these numbers are abundant (M4825, A5010) and deficient (M0514, A5100) numbers. Odd primitive abundant numbers (M5486, A6038) are: 945, 1575, 2205, 3465, 4095, 5355, 5775, 5985, 6435, 6825, 7245, 7425, 8085, 8415, 8925, 9135, 9555, 9765, 11655, 12705, 12915, 13545, 14805, 15015, 16695, 18585, ..., . Mathimatically yours, Robert G. Wilson v, PhD ATP / CF&GI Spike Jones wrote: > With every Mersenne number there is an associated perfect > number, the sum of whose factors exactly equal the number. > I discovered a fascinating thing today, for which I must introduce > some new terminology. > > If a number is greater than the sum of its factors, let it be a cold number. > If a number is less than the sum of its factors, let it be a hot number. > > Odd numbers are all cold, for instance, and the first hot number is 12. > Nowthen, I found that the ratio of cold numbers to hot numbers is > always about 3. Even when you get up to large numbers [I checked > them all up to about 100,000] the ratio seems to stay right around > 3 colds to every hot. > > Is there an embarrassingly trivial reason for this? Is there > established terminology for hot and cold numbers? spike > > _________________________________________________________________ > 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: Fri, 3 Sep 1999 09:46:16 +0000 From: "Steinar H . Gunderson" <[EMAIL PROTECTED]> Subject: Re: Mersenne: GIMPS totals. On Thu, Sep 02, 1999 at 01:16:43PM -0400, Rick Pali wrote: >My question is whether this logic has changed at all. The August 16th GIMPS >update shows me with 13.39 years and 125 exponents tested and I was >surprised to see that Tuesday's update shows 12.58 years and 127 exponents! All estimates are now based on v19, which is about 10% faster. /* 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 ------------------------------ Date: Fri, 3 Sep 1999 03:58:07 -0400 From: "Rick Pali" <[EMAIL PROTECTED]> Subject: RE: Mersenne: GIMPS totals. From: Steinar H . Gunderson > > The August 16th GIMPS update shows me with 13.39 > > years and 125 exponents tested and I was surprised > > to see that Tuesday's update shows 12.58 years and > > 127 exponents! > > All estimates are now based on v19, which is about 10% faster. Thanks to all who responded to my question. I appreciate it. 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: Fri, 03 Sep 1999 18:12:54 +0200 From: Johan Winge <[EMAIL PROTECTED]> Subject: Re: Mersenne: Several "illegal sumout" At 00:52 1999-09-02 +0200, Johan Winge (= I) wrote: > >By the way, is anyone interested in a copy of p6972593 at the 6900000th >iteration? I wasted a whole month during the summer to check it, and yes, >it turned out to be prime, regardless of all the "illegal sumout"s the >occured during the process! Since some people have been interested in it I have uploaded it to this URL: http://members.tripod.com/~Winge2/p6972593.zip Don't you people waste too many clock cycles on it though, as I did... Enjoy! - -- Johan Winge _________________________________________________________________ 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 #621 ******************************
