mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > News

Closed Thread
 
Thread Tools
Old 2005-02-26, 01:15   #67
Orgasmic Troll
Cranksta Rap Ayatollah
 
Orgasmic Troll's Avatar
 
Jul 2003

641 Posts
Default

..can I hold off on putting up the story but update my prime list?
Orgasmic Troll is offline  
Old 2005-02-26, 01:15   #68
Primeinator
 
Primeinator's Avatar
 
"Kyle"
Feb 2005
Somewhere near M52..

11100100102 Posts
Default

Okay, can you explain the differences between all these different systems- i.e. the one that Tony uses, the Alpha based system, and any others that you can think of? Thanks,

-Kyle
Primeinator is offline  
Old 2005-02-26, 08:52   #69
akruppa
 
akruppa's Avatar
 
"Nancy"
Aug 2002
Alexandria

2,467 Posts
Default

Congratulations everyone!

Btw, the new prime is not part of a twin prime pair, 2^(not-yet-official-exponent)-3 is divisible by 5.

Alex
akruppa is offline  
Old 2005-02-26, 12:19   #70
Jeff Gilchrist
 
Jeff Gilchrist's Avatar
 
Jun 2003
Ottawa, Canada

2·32·5·13 Posts
Default

Quote:
Originally Posted by Primeinator
Okay, can you explain the differences between all these different systems- i.e. the one that Tony uses, the Alpha based system, and any others that you can think of?
There are lots of differences and it can get very technical, but I will just provide some basic highlights. To get more specific details you can check out Intel. AMD, and HP's websites for more.

First, I have no idea what machine the GIMPS user was using but there is a good chance it was an AMD Athlon/Opteron, or Intel P3/P4 processor. Those are you basic 32bit processors using x86 instructions that you find in PCs.

Tony is using a machine with Intel Intel Itanium2 processors. This is a 64bit processor using ia64 instructions and is completely different from a Pentium processor. You cannot run code compiled for an Itanium on a Pentium CPU.

I am using HP Alpha processors which are 64bit and use a RISC instruction set. These are completely different from the x86 instructions and the ia64 instructions.

The idea of using different architectures and different source code to verify the suspected prime is that it is extremely unlikely that random errors in two different machine architectures and two different types of source code would both show that an exponent is prime when it is not. So the fact that the GIMPS user and Tony both agree the exponent is prime is good enough evidence to support that. That by itself is good enough from a statistical point of view, and when my run finishes it will add even more support (I'm already half way through so I might as well finish).

Jeff.

Last fiddled with by Jeff Gilchrist on 2005-02-26 at 12:21
Jeff Gilchrist is offline  
Old 2005-02-26, 16:29   #71
Mike
 
May 2004
Vancouver, Canada

22×52 Posts
Default

Congrats everyone!
Mike is offline  
Old 2005-02-26, 16:42   #72
Primeinator
 
Primeinator's Avatar
 
"Kyle"
Feb 2005
Somewhere near M52..

2·457 Posts
Default

Okay thanks. I've heard some things about a 64bit processor vs. a 32bit processor, and I know the 64bit one is signifcantly more powerful, but just how much faster is it? (I think I heard that it doesn't increase on a regular scale, i.e. a 64bit would be 2x as fast as a 32bit, but on an exponential scale, making a 64bit 10x or <insert larger number here>x faster. Can anyone verify this?)

Last fiddled with by Primeinator on 2005-02-26 at 16:46
Primeinator is offline  
Old 2005-02-26, 17:05   #73
PrimeCruncher
 
PrimeCruncher's Avatar
 
Sep 2003
Borg HQ, Delta Quadrant

2·33·13 Posts
Default

Quote:
Originally Posted by Primeinator
Okay thanks. I've heard some things about a 64bit processor vs. a 32bit processor, and I know the 64bit one is signifcantly more powerful, but just how much faster is it? (I think I heard that it doesn't increase on a regular scale, i.e. a 64bit would be 2x as fast as a 32bit, but on an exponential scale, making a 64bit 10x or <insert larger number here>x faster. Can anyone verify this?)
In the Hardware forum there is a thread on 64-bit processors and the trial factoring improvements.
PrimeCruncher is offline  
Old 2005-02-26, 17:16   #74
Primeinator
 
Primeinator's Avatar
 
"Kyle"
Feb 2005
Somewhere near M52..

2×457 Posts
Default

Thanks.
Primeinator is offline  
Old 2005-02-26, 18:35   #75
Jeff Gilchrist
 
Jeff Gilchrist's Avatar
 
Jun 2003
Ottawa, Canada

2·32·5·13 Posts
Default

Quote:
Originally Posted by Primeinator
Okay thanks. I've heard some things about a 64bit processor vs. a 32bit processor, and I know the 64bit one is signifcantly more powerful, but just how much faster is it?
It all depends on what you are trying to do. Also don't forget that the new AMD64 and Intel P4/Xeon processors are basically 32bit processors with 64bit extensions added, where as the Itanium and Alpha processors were designed as 64bit processors from the ground up.

Jeff.
Jeff Gilchrist is offline  
Old 2005-02-26, 19:06   #76
jinydu
 
jinydu's Avatar
 
Dec 2003
Hopefully Near M48

2×3×293 Posts
Default

Quote:
Originally Posted by philmoore
This also makes George the first person to be a co-discoverer of 8 Mersenne primes! Way to go! Now on to M43!
www.mersenne.org has been updated to reflect this (although it still doesn't mention the verification).
jinydu is offline  
Old 2005-02-26, 23:59   #77
dsouza123
 
dsouza123's Avatar
 
Sep 2002

12268 Posts
Default

Congratulations on the discovery of M42 !

Concerning the difference of an Opteron/Athlon 64 (AMD64)
or P4/Xeon (EMT64) versus a 32-bit x86, the pure 64 bit mode
has been streamlined and enhanced.

There are double the number of integer registers, 16 instead of 8, and
the size has doubled to 64 bits from 32 bits.
This will allow a doubling of trial factoring speed.

There are more SSE2 64-bit floating point registers.
This should add a very small increase in speed,
the major advantage is a much enhanced memory access system,
mainly on AMD64, with a different enhancement for Intel,
that should allow higher memory throughput which is crucial in the DWT transforms of the lucas lehmer test.
How much of an increase remains to be seen.
dsouza123 is offline  
Closed Thread

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Are Bitcoins Prime Related a1call Miscellaneous Math 23 2020-09-17 13:17
Prime-Related History: Leibniz' "Universal Language Based on Primes" ewmayer Math 10 2007-03-02 12:47
holy tethered cow! new Mersenne prime? (M43-related) ixfd64 News 265 2006-01-04 09:47
Mersenne prime related shirts and other items adpowers Lounge 40 2004-08-12 22:05
some prime-related trick questions ixfd64 Puzzles 2 2003-09-23 12:53

All times are UTC. The time now is 10:10.

Mon Mar 8 10:10:27 UTC 2021 up 95 days, 6:21, 0 users, load averages: 1.35, 1.47, 1.33

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.