Mersenne Digest         Tuesday, March 6 2001         Volume 01 : Number 823




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Date: Sat, 3 Mar 2001 20:56:17 -0500
From: "Olivier Langlois" <[EMAIL PROTECTED]>
Subject: RE: Mersenne: Lack of pure mathematics coverage.

Hi Joshua,

Give us the link to the article and I'll read it send my comments to the
editor.

> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Joshua
> Zelinsky
> Sent: Saturday, March 03, 2001 7:11 PM
> To: [EMAIL PROTECTED]
> Subject: Mersenne: Lack of pure mathematics coverage.
>
>
> I'm trying to start an e-mail campaign for Sciencedaily.com
> to pay more
> attention to pure mathematics. What really irks me is that
> they had a recent
> article (12/14/00) about distributed computing that spent half of the
> article on SETI and didn't mention us at all! They didn't
> mention Ensor
> computing either. Maybe the problem isn't that people find SETI more
> enjoyable but that the media does. Anyways, if you could send
> e-mails to
> [EMAIL PROTECTED], I would sincerely appreciate it.
>                                                 Sincerely,
>                                               Joshua Zelinsky
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Date: Sat, 03 Mar 2001 21:20:21 -0500
From: "Joshua Zelinsky" <[EMAIL PROTECTED]>
Subject: RE: Mersenne: Lack of pure mathematics coverage.

Thanks,
   The link is http://www.sciencedaily.com/releases\2000\12\001214082350.htm

Sincerely,
   Joshus Zelinsky
_________________________________________________________________
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Date: Sun, 4 Mar 2001 06:05:16 -0800 
From: Paul Leyland <[EMAIL PROTECTED]>
Subject: Mersenne: Factoring on elderly machines.

Three weeks ago, I wrote:

> The integer factoring people can always use more cycles, and 
> even antique machines make valuable contributions in a reasonable
> time.  For instance, I have small number of DECstations and a Sun
> SS2 on my home network all running the ECMNET client.  These
> boxes are perhaps as powerful as a 486DX2-66.

A few days ago my DECstation 5000/240 found a 32-digit factor of
Cullen(831), that is 831*2^831+1, with the ECMNET client.  Ok, so it's not a
Mersenne number but the ECMNET server could just as easily be loaded with
them.


Owners of elderly machines should not despair just yet.

Paul
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------------------------------

Date: Sun, 04 Mar 2001 21:12:19 -0500
From: vincent mooney <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Factoring on elderly machines.

At 06:05 AM 3/4/01 -0800, Paul Leyland wrote:
>Three weeks ago, I wrote:
>
>> The integer factoring people can always use more cycles, and 
>> even antique machines make valuable contributions in a reasonable
>> time.  For instance, I have small number of DECstations and a Sun
>> SS2 on my home network all running the ECMNET client.  These
>> boxes are perhaps as powerful as a 486DX2-66.
>
>A few days ago my DECstation 5000/240 found a 32-digit factor of
>Cullen(831), that is 831*2^831+1, with the ECMNET client.  Ok, so it's not a
>Mersenne number but the ECMNET server could just as easily be loaded with
>them.
>
>
>Owners of elderly machines should not despair just yet.
>
>Paul

Speaking for myself, having completed over 260 factorings over 5 years,
with no primes found, I say that elderly owners of machines should not
despair just yet.

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------------------------------

Date: Mon, 05 Mar 2001 09:54:24 -0400
From: "Michael F. Yoder" <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Factoring on elderly machines.

On the subject of people with older machines despairing: on a Sun workstation my
primitive-trinomial program takes about 10 hours (but depending on how many
other engineers are using the machine) to test a q value for Richard Brent's
distributed computing project.  (It is to find primitive trinomials x^p + x^q +
1 over GF(2) where p is a Mersenne exponent.)  I recommend this project highly
for GIMPS folks because these trinomials are actually useful, and, as far as I
know, they are the only actual application of finding Mersenne primes.  (These
trinomials are important in making pseudorandom number generators.)  It is even
imaginable that the project could "catch up" with GIMPS because new work is only
created when a Mersenne prime is found.

So, if you'd like to put slow machines to good use, follow the "Other Projects"
link and then the "search for primitive trinomials" link on the page you arrive
at.

Mike Yoder


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------------------------------

Date: Mon, 05 Mar 2001 18:42:42 +0100
From: Guillermo Ballester Valor <[EMAIL PROTECTED]>
Subject: Mersenne: More than 10000 athlons!.

Hi all:

Last weekend the number of AMD-athlons registered in Primenet has
reached 10000. In few weeks they will be the most popular among GIMPSers
if the actual trend continues.

George, it is possible an optimization for Athlons?. I mean if it is
worthwhile, as far as I know (I'm possibily wrong) the documentation for
AMD-processors is no so clear as for Intel's. 

Regards.

Guillermo.
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Date: Mon, 5 Mar 2001 20:01:31 -0000
From: "Brian J. Beesley" <[EMAIL PROTECTED]>
Subject: Re: Mersenne: More than 10000 athlons!.

On 5 Mar 2001, at 18:42, Guillermo Ballester Valor wrote:

> Last weekend the number of AMD-athlons registered in Primenet has
> reached 10000. In few weeks they will be the most popular among GIMPSers
> if the actual trend continues.

Not surprising, since (a) 1.2 GHz Athlons seem to be reasonably 
readily available, whereas PIII's faster than 1GHz either don't exist 
or don't work; (b) at a given clock speed and running Prime95 or 
mprime (code written for Pentium Pro), Athlon outperforms PIII by at 
least 25%; (c) Athlon CPUs are also cheaper than PIIIs, and _much_ 
cheaper than P4s, whilst the cost of the other components needed to 
build a system is at least no worse. (P4s require at least two 
expensive RIMM modules to function at all).
> 
> George, it is possible an optimization for Athlons?. I mean if it is
> worthwhile, as far as I know (I'm possibily wrong) the documentation for
> AMD-processors is no so clear as for Intel's. 
> 
An optimization should be possible. The cache structure is different 
to the Intel model, in particular the L1 cache is enormous compared 
with the Intel design; the associativity and granularity is also not 
the same. It _may_ be possible to achieve around 5% improvement by 
tuning memory accesses to the cache structure. 

I don't know whether you'd need a different scheme for the Duron - 
which is the same as the current Athlon (Thunderbird) except that it 
has only 64KB of level 2 cache, and is (as yet) available only in 200 
MHz FSB (technically double-data-rate clocked at 100 MHz) whereas 
faster Athlons are now also available with 266 MHz FSB.

The FPU timings and throughput are different - actually the increase 
in FFT performance over the Pentium is precisely because of this, 
though there may be some room for further improvement by re-ordering  
instructions in some of the macros.

As for documentation, I gather that Intel's published documentation 
on the P4 is not that great, either ...

Having said all that, the performance gained by optimizing for Athlon 
would be an improvement rather than a whole new ball game - whereas 
the opposite is true in the case of the P4!

BTW I'm now running two Athlons (1.2 GHz & 650 MHz), though neither 
show up in the PrimeNet statistics as they're both doing QA runs on 
large exponents.


Regards
Brian Beesley
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------------------------------

Date: Tue, 06 Mar 2001 16:59:33 +0100
From: "Siegmar Szlavik" <[EMAIL PROTECTED]>
Subject: reports corrupt? was: Mersenne: More than 10000 athlons!.

On Mon, 05 Mar 2001 18:42:42 +0100, Guillermo Ballester Valor wrote:

>Last weekend the number of AMD-athlons registered in Primenet has
>reached 10000. In few weeks they will be the most popular among GIMPSers
>if the actual trend continues.
>
Hi,

I wanted to take a look at the statistics, but it seems that there is 
a problem with the hourly updated (status) reports - or am I the only
one who has this problem? btw: would it be possible to get those huge 
status.txt and cleared.txt files in a compressed (gzip?) format? This
would definitively save download time and bandwith...

greetings,

Siegmar



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