Mersenne: Squaring huge numbers
I am investigating 64-100 sequences, which are chains of bases such that the number written 100 in each is written 64 in the next (e.g. 8,10,16,42). I quickly wrote a Python program to compute them. It is now computing the square of a 1555000 digit number and has been doing so since the 17th. What squaring algorithm is Python using? Is there a faster way of squaring numbers where the number of digits doubles at each iteration? phma -- .i toljundi do .ibabo mi'afra tu'a do .ibabo damba do .ibabo do jinga .icu'u la ma'atman. _ Unsubscribe list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Crypto scientists crack prime problem, not Redmond journalists
On Saturday 17 August 2002 03:22, Halliday, Ian wrote: In http://msn.com.com/2100-1104-949170.html?type=pt we read Crypto scientists crack prime problem To create encryption keys, RSA uses two huge prime numbers and multiplies them together to produce an even bigger prime. The hard problem RSA relies upon is not finding whether a number is prime, but finding its factors if it isn't. But someone who thinks that the product of two prime numbers is prime doesn't know the difference. Then there's the discrete logarithm problem, which he probably doesn't know from the concrete logrolling problem. phma _ Unsubscribe list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: mprime crashes but Prime95 doesn't
I got a new laptop a few weeks ago. I promptly loaded Linux on it and ran into hardware problems. I copied statically linked mprime to it and ran it; it crashed in a few minutes. I sent it back. The technician knows nothing about Linux. He loaded Windows and ran some test, which found nothing. I told him about mprime, so he loaded Prime95 on it and ran it for at least a day with no errors. The processor is an Athlon. The kernel I ran on it was 2.4.17 from a Sourcemage install. Is there any problem with that version? phma _ Unsubscribe list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Trace/breakpoint trap
I have a new laptop which has some problems. First I ran tartest (a program I wrote which repeatedly untars the kernel source and compares the results) and found that one memory module is bad and the other is good. Next I found that when it compiles Linux, the result doesn't work. So I copied mprime (static version) from my desktop box which is running it, ran a stress test, and within a few minutes got Trace/breakpoint trap and it quit. This is running the kernel on the CD, not the one I compiled which doesn't work. What does that mean? phma _ Unsubscribe list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: mprime crashes in linux 2.4.8
I was running mprime 21.4.2 under Linux 2.4.3 for many months with no problem. I just rebooted into 2.4.8 (both are stock kernels from Mandrake) and mprime segfaulted. I ran gdb on it and got the following: [root@littlecat mersenne]# gdb GNU gdb 4.17.0.4 with Linux/x86 hardware watchpoint and FPU support Copyright 1998 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type show copying to see the conditions. There is absolutely no warranty for GDB. Type show warranty for details. This GDB was configured as i386-redhat-linux. (gdb) file ./mprime Reading symbols from ./mprime...(no debugging symbols found)...done. (gdb) run Starting program: /win/mersenne/./mprime (no debugging symbols found)...(no debugging symbols found)... Program received signal SIGSEGV, Segmentation fault. 0x8172105 in _IO_stdin_used () (gdb) where #0 0x8172105 in _IO_stdin_used () #1 0x40015c24 in _dl_debug_mask () #2 0x8056136 in strcpy () #3 0x80744bc in strcpy () #4 0x8073dde in strcpy () #5 0x4005e5b0 in __libc_start_main () (gdb) [root@littlecat mersenne]# gdb GNU gdb 4.17.0.4 with Linux/x86 hardware watchpoint and FPU support Copyright 1998 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type show copying to see the conditions. There is absolutely no warranty for GDB. Type show warranty for details. This GDB was configured as i386-redhat-linux. (gdb) file ./mprime Reading symbols from ./mprime...(no debugging symbols found)...done. (gdb) run Starting program: /win/mersenne/./mprime (no debugging symbols found)...(no debugging symbols found)... Program received signal SIGSEGV, Segmentation fault. 0x8172105 in _IO_stdin_used () (gdb) where #0 0x8172105 in _IO_stdin_used () #1 0x40015c24 in _dl_debug_mask () #2 0x8056136 in strcpy () #3 0x80744bc in strcpy () #4 0x8073dde in strcpy () #5 0x4005e5b0 in __libc_start_main () (gdb) ldd returns the following information: libm.so.6 = /lib/libm.so.6 (0x4001f000) libc.so.6 = /lib/libc.so.6 (0x40042000) /lib/ld-linux.so.2 = /lib/ld-linux.so.2 (0x4000) What's wrong? _ Unsubscribe list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: taxifornia brownout
On Sat, 09 Jun 2001, vincent mooney wrote: I'd guess that sales of UPS's are on the upswing. So how will that affect FedEx? phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Getting new GIMPSers
On Sun, 25 Mar 2001, John R Pierce wrote: Hmm ... my comp has NO idle time anymore (8 even with prime95 running 24/7 on my Windows2000 system, it seems to come up with a FEW idle cycles. I figure its when prime95 gets paged out or something. I rebooted a couple of hours ago after photoshop blew up and left the system kinda crispy, in the past 2h 48m, I show 3 minutes of idle time has accumulated. 2:43 has gone to prime95. the rest to everything else i've done (hardly none to a number of edit windows, web browsers, etc). How does idle time accrue *to a process*? Idle time is when the CPU is not executing any process. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Getting new GIMPSers
On Sun, 25 Mar 2001, Jeff Woods wrote: At 10:03 AM 3/25/01 -0500, you wrote: even with prime95 running 24/7 on my Windows2000 system, it seems to come up with a FEW idle cycles. I figure its when prime95 gets paged out or How does idle time accrue *to a process*? Idle time is when the CPU is not executing any process. On a Win32 system, the idle time is kept track of by the idle PROCESS (a thread or task operating autonomously, for you *n*x types). It is by hooking into and pseudo-taking over this process that Prime95 does its work. You're ignoring the context of my question. The context was: even with prime95 running 24/7 on my Windows2000 system, it seems to come up with a FEW idle cycles. I figure its when prime95 gets paged out or something. I rebooted a couple of hours ago after photoshop blew up and left the system kinda crispy, in the past 2h 48m, I show 3 minutes of idle time has accumulated. 2:43 has gone to prime95. the rest to everything else i've done (hardly none to a number of edit windows, web browsers, etc). I know that there's an idle process (#0), an init process (#1), and many other processes in a computer. Idle time accrues to the idle process. What I don't understand is how 2:43 of the idle time was accounted to prime95 and the other seventeen seconds to other processes - it should all have been accounted to the idle process. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: GIMPS in the news
On Sun, 07 Jan 2001, Russel Brooks wrote: http://www.nashuatelegraph.com/Main.asp?UID=35947505SectionID=30SubSectionID=90ArticleID=23815 While I am the geek brother mentioned in the article I make no claim as to the accuracy of the article. What does "factor pi" mean? phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: More on Compression
On Tue, 28 Nov 2000, Nathan Russell wrote: However, the question we must consider is whether saving space in a 1-meg executable is worth the extra trouble for all concerned, as well as using a non-standard compression format. If you want to keep stuff compressed on your disk, use the e2compr patch. This will compress any regular file and all programs that read or write the file will see it just as if it were uncompressed. It does occasionally crash the computer, though. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Soft modem
There are hard internal modems. Look at the instructions on how to install it for Linux. It may say that you just make a symbolic link /dev/modem to an existing device, or it may have you make a device /dev/ttyS4 and run setserial on it, and still be a hardware modem. But if you have to install a driver, which will be a file with a .o extension, it's a software modem. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.exu.ilstu.edu/mersenne/faq-mers.txt
Mersenne: NFSNET
Anyone know what happened to Conrad Curry? His page has been saying for months that 2,679- is 40% sieved, but when I tried to get another range to sieve, the script appears to have run out of ranges. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.exu.ilstu.edu/mersenne/faq-mers.txt
Mersenne: PNG (good!)
I sort of doubt it. The whole GIMPS project is oriented to techie types. Types who like to stay current with the latest technology and would upgrade their browsers frequently. Also add in the fact that Internet Explorer, last I heard, is gaining popularity and that IE4 and IE5 support PNGs (haphazardly, but enough for banner purposes), and that Microsoft practically forces people at gunpoint to upgrade, and so I'm guessing almost all IE users can see PNGs. In addition, newer versions of Netscape can see PNGs. That leaves, like, the Netscape 3 users. I really doubt that there are that many Netscape 3 users out there. (Doesn't it have the most primitive level of Javascript support and whatnot as well? Hopefully that would have annoyed users into upgrading by now. It sure did for me and IE3.) Maybe someone who's a webmaster could check their server logs and see how many non-PNG compliant people are viewing their pages; it'd be rather representative if Mr. Kurowski could do that. I think it'll be a small minority, maybe an order of magnitude higher than the number of people who still use Lynx. Netscape 4.08 supports PNG but ignores the alpha channel. kfm understands the alpha channel, but only on or off - it borderlines it at 7f or 80; and when it prints a page with a PNG in it, the alpha is ignored. I recently had to do layer surgery on a PNG because it didn't print right. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.exu.ilstu.edu/mersenne/faq-mers.txt
RE: Mersenne: Date: Sun, 30 Jul 2000 18:53:50 +0200
I understand. I didn't think at Prime95 so much using the bus (in fact, in Paris the Metro is far more convenient). But you wouldn't want it searching all the arrondissements for primes, as then it would go at a snail's pace. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.exu.ilstu.edu/mersenne/faq-mers.txt
Re: Mersenne: V20 beta #3
A question to all you linux users with modems: I assume that the /proc/net/route file exists when you are not connected. Let me know if this is not the case (I'll need to change the default setting of RouteRequired above). I have a modem and an Ethernet card on one box. The file exists whether I'm on or off line, but the "ppp0" lines are there only when I'm on line. To tell when you're on line, look for a gateway in the "Flags" column, which says 4003 for the gateway and 1 for an Ethernet connection. (I don't know which bit means gateway.) This will work only if the dialup machine is the one running mprime. If mprime is behind an IPmasq box, you have to ask the IPmasq box if it's online. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: GIMPS in Science News
M(17) is the number of people that could fit into a /very/ large open arena or stadium. What stadium is that big? The one at Urbana seats only about 2. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: hackerz attackerz
So my question to the sysadmins out there is: what's the best way to avoid this sort of thing, without installing a firewall and while still permitting ftp access? In re-reading the DEC Unix manpage for ftpd, it seems to me the weakest link is the guideline for the ~ftp/pub directory, which the manpage says to make owned by ftp and writeable by anyone. I've changed it to be owned by root and unwriteable except by root, but that may not be an option for folks who maintain public ftp archives that multiple users must be able to write to. Make sure that no one logging in as anonymous can write to the ftp archive (which it sounds like you did), and no one can log in as himself and upload anything (which I'm not sure how to do). Allow only rsync, either with modules or over ssh, to update the ftp space. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Can I reserve the poaching thread? ;-)
On Fri, 11 Feb 2000, Paul Landon wrote: May I exclusively reserve the topic of "poaching"? ;-) I will release it in 60 days. (unless it is completed by someone else before then). I think we should forge ahead. The hunter poached eggs and the blacksmith forged checks. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Where's the flaw in my thinking?
If we left shift this by the position of the 1, for each 1 in the binary representation, and add them together, we should get the square... So to square 14, we do this: 1110 3 == 111 + 1110 2 == 0111000 + 1110 1 == 0011100 + == 11000100 which is 196 So for each squaring, we have x left shifts and adds, where x is no larger that p. In any case... is this just me being dumb and missing that this is just a stupid way of squaring a number? It is not stupid, it is in fact the normal way of squaring a small number. The reason humongous numbers are squared with FFT is that shift-and-add takes O(n^2) bit operations, where n is the number of bits in the number being squared, whereas FFT takes O(n*ln(n)*ln(ln(n))), which is a lot faster. The FFT of n floats takes log_2(n) stages, each of which runs through the array once which takes n operations; the ln(ln(n)) term (please correct me if this term is wrong) is because the more bits there are in the number you are squaring, the more precisely you need to compute the floats in the FFT. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Fwd: Re: Mersenne: Re: Base e arithmetic
This led to a discussion as to whether or not it is possible to have a number system based on a non-integer base. Maybe the great minds of GIMPS can contribute to this. Base phi is easy to compute in. The similar Fibonacci representation counts the integers as follows: 0,1,10,100,101,1000,1001,1010,1,10001,10010,10100,10101... No number has two 1-bits adjacent. Complex bases can also be used. i-1 is usable as a base, but i+1 is not, because 2 cannot be finitely represented. Gosper's representation uses seven digits, the sixth roots of 1 and 0, in base 2.5+sqrt(-3/4). phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: Smooth and hairy numbers
On Thu, 03 Feb 2000, [EMAIL PROTECTED] wrote: If smooth numbers are ones whose prime factors are all small, what then are hairy numbers? Is there an official definition? "And Jacob said to Rebekah his mother, Behold, Esau my brother is a hairy man, and I am a smooth man:" (Gen. 27:11) Also, Greek has smooth and rough breathing, called psilé kai daseia. Daseia means hairy. I looked in Eric Weisstein's World of Mathematics and found no hairy numbers. There are, though, a Hairy Ball Theorem (the hair has to have a whorl or other singularity somewhere) and Haar integral, function, measure, and transform (one cycle of a square wave at a power-of-two frequency). phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Version 20 memory questions
However, I assume that it will be possible to specify (change) what hours are the ON hours. I suppose that midnight to 06:00 would be fine for most people, as a default. This probably depends on your distro. Red Hat and Mandrake run their crontabs between 4 and 5 in the morning, so that hour may be bad; but those processes, which consist of building a database of all the files on the disk and all the man pages, are I/O bound, not compute bound. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Size of largest prime factor
If I pick a huge number n at random, how much smaller than n, on average, is its largest prime factor? phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Interesting/Annoying Mersenne Side-Effect
On Thu, 13 Jan 2000, gregory czajkowski wrote: Hello All, I've been involved in GIMPS for about 2.5 years now, several machines, OSes. Recently I installed prime95 on a IBM Intellistation Dual uproc. It seems my combination of soundcard+headphones is VERY sensitive since when I'm running 1/2 prime95s I can "hear" them chugging along on the headphones. There is a low volume high pitch periodic (2/s) noise emanating from the speakers. As soon as I turn prime95 off, it ceases. The volume setting has no effect on it. Has anyone else had this problem? I'm pretty sure its a faulty sound-card, just wondering if anyone had an idea on how to fix it. I run prime95 on a machine at the office and mprime here. I can hear it running on the machine at the office. The sound card on the box running mprime doesn't work in Linux, and it's a 486 anyway so it's doing factoring. The box at the office is a Pentium. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: How to set up mprime on a dual boot machine?
On Sun, 26 Dec 1999, Kevin Sexton wrote:
I have prime95 running on win95, and have set up mandrake,
and I want mprime to continue the work, right now, linux is
only run a minority of the time, and I haven't set up a
compatible modem, but this will change. I am new to linux,
and so I don't know the details of how to set it up in the
scripts, ect.
Put mprime in the same directory as prime95 (mine is /win/mersenne). I start
mprime from rc.local, though it would be better to start it from a script in
init.d as then if I switch runlevels I wouldn't end up with two mprimes running
at once.
/win/mersenne/mprime -d |/usr/local/bin/runtail 25 /win/mersenne/primelog
runtail is a Tcl script which is attached. You may want to run mprime on a
virtual console or from screen.
phma
#!/usr/bin/tclsh
# Reads standard input and writes the last n lines to a file.
# Usage: runtail n file
proc outem {} {
global n ;
global file;
global line ;
set f [open $file w];
for {set i 0} {$i $n} {incr i} {puts $f $line($i)};
close $f;
}
proc scroll {str} {
global n;
global line;
for {set i 1} {$i $n} {incr i} {set line([expr $i - 1]) $line($i)};
set line([expr $n - 1]) $str;
}
foreach {n file} $argv {}
for {set i 0} {$i $n} {incr i} {set line($i) ""}
while {1} {
scroll [gets stdin];
outem;
}
Mersenne: mprime 19.1 glibc
I'd like to upgrade mprime, and I see it's linked with glibc 2.1. I have glibc 2.0.7. Will it work? I'm currently running 18.1. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: GIMPS in Dallas Morning News
http://www.dallasnews.com/technology/1202ptech9pcs.htm _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: Trial-factorers
Anybody care to port bash to Windows? (Oh well, it has probably been done already...) It has been done, and you need only operate swans. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: (2^p-1)/p == 0 (mod 3) ?
On Tue, 26 Oct 1999, Alexander Kruppa wrote: Hello all, a simple Number Theory question. Is always (2^p-1) / p ,odd prime p, divisible by 3 ? I assume you mean truncated integer division, as real division makes no sense here. It isn't if p=3 (7/3=2), but 2^p-2 is divisible by 3. (2^n) mod 3 is 1 if n is even, 2 if n is odd. If p=5, 2^p-1=31, and 31/5=6, so it is true for 5. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: mprime startup at boot-time
Secondly, I used to feed the output to a virtual terminal, but decided that having a hard copy that I could periodically check was better. I've been piping all the output to a file, such as mprime -d /home/GIMPS/tracking.txt. When it finishes reporting a result, I delete everything but the result and let mprime continue on to the next LL test using the same file. If you delete a file while a program is writing to it, it will keep on writing to the now nameless file, and will keep eating up disk space, until the program quits or closes the file, at which time the file will disappear. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: FFTW for GIMPS?
When did using 10-byte reals become common? As far as I remember, you don't even have a store instruction for that. The 80-bit load is slower than the 64-bit load too, I think. Win32Forth can be compiled either way. Here's some of the code from FLOAT.F: B/FLOAT 10 = [IF]synonym FSIZE extended [ELSE] synonym FSIZE double [THEN] code fpush ( f: r -- ) ( fs: -- r ) \ push on simulated stack mov ecx, FSP [edi] fstpFSIZE FSTACK [ecx] [edi] fwait add ecx, # B/FLOAT mov FSP [edi], ecx next, end-code code fpop ( f: -- r ) ( fs: r -- ) \ push on real stack mov ecx, FSP [edi] sub ecx, # B/FLOAT js L$1 fld FSIZE FSTACK [ecx] [edi] mov FSP [edi], ecx \ fwait jmp L$2 _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: complaint
On Thu, 16 Sep 1999, Steinar H. Gunderson wrote: On Thu, Sep 16, 1999 at 01:06:04PM +0200, Harald Tveit Alvestrand wrote: One version of Linux has paid the bill and passed the test, so at least one version of Linux is Unix. If you wanted to be picky, you could always say that a version of _GNU_/Linux has passed the test... The tests aren't for the kernel only, are they? But "GNU" stands for "GNU's Not Unix!", so how can it be Unix if it isn't? phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: Merced Assemblers
And gas, taking the bloatedness to new heights, will require 8 bytes of memory, 32 kB of hard disk space (making it impossible to compile Merced code on a C64 -- the gas team has already issued a public apology for this) and a toaster. Gasp! (No, I won't buy an assember. An assembLer, on the other hand ;-) ) What month comes after Assember? phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Closing a 9x Program
On Thu, 05 Aug 1999, Arnold R. Hart wrote: I have a laptop and can't seem to figure out how to run prime95 when the laptop is plugged in, but not when it is operating on battery power. I'm running MS Win'98. (release 2???) The powermanagement software will let me start prime95 (18.1) when I boot, but if I log-off, then prime95 exits. If I install prime95 as a service, then I can't seem to shut it down via the power save since I didn't start it via the power save software. As I see it, the easiest solution would be to find a way to close it from the command line. My power save software allows me to set "warnings" that will run given programs when the batery gets below a certain level. I'd like to, unless there is a better solution, set a warning at 99% that would run a batch file to close prime95. Is this possible? I don't know if it's possible to suspend a program from the command line in Windows, but if there's a way to do it, you can probably do it with kill in Cygwin. (I don't know offhand if Cygwin has kill.) I have a cron job on the laptop that automatically starts nfsieve (I'm running mprime on the desktop) if it isn't running and nfs.out exists, renices it, and suspends it if the battery is low or restarts it if it is high. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Fermat number others
- Long ago ;-) I made some investigations about the period of inverse of prime numbers (1/p) (Is this good English ?). I found an empiric relation between the number of digits of the period (d) et the fact that p is prime, namely that d is a divisor of p-1. I have been told that this was proved by Gauss. Is there a Web page about this ? Is this could be of any use in the search for large primes ? The number of digits in the period is whatever power of 10 you need to make 1 mod p. If 10 is a primitive root of p, then the period is p-1. Ex. 1/7=.(142857), 1/17=.(0588235294117647). 16, of course, is not a primitive root of anything, so reciprocals never have full period in base 16, and most of them have odd period. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Computing noises; was Worth it?
(Off topic, when I computed that value in Landon's Calc program, my computer PII/233 started making a weird humming noise. The noise stopped when the calculation finished. Very strange indeed...) I'm running Prime95 on a computer at the office, and it emits faint cricketish noises from the speakers while it's working. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Squaring algorithm...
On Thu, 22 Jul 1999, Blosser, Jeremy wrote: Just was thinking the other day about this... Forgive me if its been discussed before etc. Aren't there other "better" algorithms for finding the square of a number besides using an FFT? Sure an FFT is great for multiplying two different numbers, but for squaring a number isn't the case a little different. Plus, going off what I've read on FFT's, it runs in O(n log n) time. It runs in O(n log n) time where n is the number of digits in the number being squared, not the number being squared itself. Given any algorithm for squaring, there is an algorithm for multiplying that runs at the same speed to within a constant factor, and vice versa. Squaring is multiplying a number by itself, and multiplying can be done by subtracting the square of the difference from the square of the sum and dividing by 4. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Primes for money
What do you call someone who searches for primes only because of the prize money? A mersennary. phma _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Laptop users: Automatically suspend sieve, mprime, etc. when off the grid
I run sieve on a laptop, and I don't want to run the battery down with sieve when it's not plugged in to the wall. So I wrote the following shell scripts, which start it automatically, run it nicely, and suspend it when the battery is low. You will have to have APM in your kernel to get anything useful out of battery. Be sure to change the home dir to yours. Note: This is run from the crontab every minute. Cron does not use your normal shell environment. That is why the path to sieve is spelled out. phma batcheck sieben #!/bin/sh cut -f 7 -d " " /proc/apm
Re: Mersenne: Head's algorithm for multiplying mod n
On Thu, 08 Jul 1999, Brian J. Beesley wrote: On 8 Jul 99, at 6:19, Lucas Wiman wrote: In the book _Primes and Programming_ Head's method of multiplying two numbers mod n is mentioned. Is this actually more effiecient than simply multiplying the two numbers and taking the modulus? Look at it this way. Head's method is essentially binary long multiplication, with the "wrinkle" that you take the remainder modulo n after each shift add operation. That is going to be a *lot* slower than FFT convolution, for numbers the size of the Mersenne numbers we're testing! FFT is O(n*log(n)) where n is the number of limbs in the numbers being multiplied. Head's method is O(n^2), with O being slightly smaller than for straight long multiplication. A recursive method splitting the number in the middle, then doing a subtraction trick to make three instead of four submultiplies, is O(n^y), where y is log(3)/log(2), which is about 19/12. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Head's algorithm for multiplying mod n
Limbs? It is good to know that the world has many different literal meanings in many languages for "bits" - variety is good for us all. (The French word for "buffer" is also, I seem to remember, rather amusing). "Limb" is the term used in gmp for a digit in a large base (such as 2147483648) in which a number is represented in a multiple-precision package. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Linux VFAT question
But the fact is that the performance of my mounted hdd win98 (vfat) partition is very low. All my normal linux (ext2) partitions work with normal performance. If I execute a command like `ls -l /Win98` (/Win98 is the path of may win98 (vfat) partition) it takes more than a second to get the result. The second points is, that the swapping seems to be slower than without running mprime. I run mprime every time at the lowest priority. cd to various directories, then type vdir|wc -l in each. This tells you how many files the directory has. The more files, the longer it takes to sort them. vdir -U lists the directory without sorting it, which is a little faster. mprime just writes once every 30 minutes, so whether it's running in the Windows drive or the Linux drive is inconsequential. As to the swapping, the swap daemon runs at 12 naughty, so I don't see why mprime at 20 nice would bother it at all. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Re: Self-test (was: Prime 95 Error Messages/ Misc)
Most modern motherboards contain case and/or CPU temperature sensors which can be read by software. Is there a file in /proc that will tell me this? phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Prime95 on linux, a tech question
On Sun, 06 Jun 1999, [EMAIL PROTECTED] wrote:
I wouldn't recommend the " /dev/null" command. If you start it remotely,
the stdout and stderr usually (but not always) go to e-mail. This way you
can still see the output and not lose any critical messages...
I pipe the output to a program that keeps the last 25 lines in a file.
phma
---
[phma@littlecat bin]$ cat runtail
#!/usr/bin/tclsh
# Reads standard input and writes the last n lines to a file.
# Usage: runtail n file
proc outem {} {
global n ;
global file;
global line ;
set f [open $file w];
for {set i 0} {$i $n} {incr i} {puts $f $line($i)};
close $f;
}
proc scroll {str} {
global n;
global line;
for {set i 1} {$i $n} {incr i} {set line([expr $i - 1]) $line($i)};
set line([expr $n - 1]) $str;
}
foreach {n file} $argv {}
for {set i 0} {$i $n} {incr i} {set line($i) ""}
while {1} {
scroll [gets stdin];
outem;
}
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Re: Mersenne: Prime95 on linux, a tech question
if ( $mersenne 5 ) then Why 5? Isn't one enough? If there is more than one running, they'll just compete with each other for the CPU, even though they're being nice to everyone else. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: HTML posts
The type you're looking for is not text/html but multipart/alternative. If it's multipart/mixed, that means there's an attachment. If the MIME type of the message were text/html, that would mean that it is just an HTML message with no text alternative. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Linux Mprime how to Auto Dialup?
The only way I can think of is having a script monitor the optional
STDOUT of mprime and then checking whether it needs to contact the
server.
I use the attached Tcl script to keep the last 25 lines of the output of mprime
in a file. You could put some commands in your crontab to check this file for
"done" and "server", and if it has "server" but not "done", connect to the Net,
but if it has "done", disconnect.
phma
#!/usr/bin/tclsh
# Reads standard input and writes the last n lines to a file.
# Usage: runtail n file
proc outem {} {
global n ;
global file;
global line ;
set f [open $file w];
for {set i 0} {$i $n} {incr i} {puts $f $line($i)};
close $f;
}
proc scroll {str} {
global n;
global line;
for {set i 1} {$i $n} {incr i} {set line([expr $i - 1]) $line($i)};
set line([expr $n - 1]) $str;
}
foreach {n file} $argv {}
for {set i 0} {$i $n} {incr i} {set line($i) ""}
while {1} {
scroll [gets stdin];
outem;
}
Re: Mersenne: Repeating LL remainders
I don't quite see how this makes it unneccessary to check only iteration numbers which are powers of 2. How long does it take to find a cycle length of, say, 127 if you're sampling only powers of 2? Let's say you have a cycle of length 127 beginning at 992. You keep 1, 2, ... 1024. When you get to 1151, you see it's the same as 1024, and you know you have a cycle. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: GUI for Linux
On Wed, 14 Apr 1999, Guillermo Ballester Valor wrote: Hi to all: Henrik Olsen wrote: On Tue, 13 Apr 1999, Ernst W. Mayer wrote: A bit off-topic, but I think there are enough Linux users out there to justify it. Check out You are right, I think. I am a new user of linux, then a new mprime user. I run both prime95/mprime in Win95/linux O.S. using the same directory and files (except the executable file, of course). 99% of iterations are made by mprime, 1% by prime95. Actually, I only use prime95 like an administartion tool to configure the *.ini files. I know I can do that simply editing the files... but I like GUI in prime95. I wrote a small tcl program to keep the last 25 lines of mprime's output in a file. I am planning to write a tcl/tk program to look at that file and tell me when mprime wants to connect and, having connected, when it's finished so that I can disconnect. But I don't know how to change the parameters of a running mprime. Can I open mprime bidirectionally from the tcl program and pass it commands? Or could mprime be modified to listen to some port, and then I could run a client to get at its menu? I run it as root, from rc.local, before any consoles are gotty. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: preventive measures
How about this?: If mprime finds that it needs to update itself, it downloads the new files, renames the old ones, renames the new ones, and quits at five 'til. One minute past the hour, a cron job notices that mprime isn't running and restarts it. phma Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm
