Mersenne Digest Wednesday, July 26 2000 Volume 01 : Number 762
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Date: Tue, 25 Jul 2000 01:23:36 +0200
From: "Martijn Kruithof" <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Assignment of Exponents
Depending on CPU power and preferences (which may override CPU power)
you get factoring, first time LL or double check, Smallest exponents are
given out
first. All exponents which are overdue are added to the list again around 6
AM GMT
These exponents may still be finished by the original owner, this is
relatively unlikely however
(5% chance I would say). In case this happens with a first time check, it
still makes sense to go on then,
and you are credited for a double check.
Kind Regards, Martijn
- ----- Original Message -----
From: "Andy" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, July 24, 2000 11:24 PM
Subject: Mersenne: Assignment of Exponents
> Just a quick question. Are the lowest exponents assigned first or is it
> dependent on your CPU power or what?
>
> _________________________________________________________________________
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>
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------------------------------
Date: Mon, 24 Jul 2000 23:15:06 -0400
From: Nathan Russell <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Error 11: exponent already tested!?!
> For those unaware of this PrimeNet feature:
>
> To extend an assignment or assignments up to 120 days, see:
>
> http://www.mersenne.org/ips/manualtests.html
>
> "Extend Exponent Assignments" toward the bottom of the page!
>
> Best Wishes,
> Stefanovic
It should possibly be added that one does not need immediate access to
the machine running the exponent to do this; all that is needed it to
copy the exponent to the form!
Nathan
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------------------------------
Date: Tue, 25 Jul 2000 13:28:53 -0000
From: "Brian J. Beesley" <[EMAIL PROTECTED]>
Subject: Mersenne: Suggestion for improving robustness of algorithm
Hi guys,
I was thinking that we could probably improve the confidence we have
in double-checked results if we adopted the following tactic.
Normally we run with the FPU set to round to nearest or even (the
default mode). Suppose we ran first tests with rounding set to round
down (towards -infinity) and double checks with rounding set to round
up (towards +infinity).
This would lose us about 1 bit precision in the mantissa, but, if a
double check run verified the residual, we'd be _certain_ that
rounding errors weren't compromising the algorithm.
We would probably have to reduce the FFT size changeover points
slightly to accomodate the small loss of precision, but would
probably be able to regain the resulting throughput loss by reducing
the frequency with which other "sanity checks" were done.
The combination of round up/round down matching and randomized offset
would surely lead to results obtained using the same program to be
less likely to match incorrectly. Not that this is a particular
problem, but we might be able to get the improvement for a very small
(or possibly even negative) cost in execution time.
Regards
Brian Beesley
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------------------------------
Date: Wed, 26 Jul 2000 08:28:16 -0600
From: "Alan Vidmar" <[EMAIL PROTECTED]>
Subject: Mersenne: NTprime service and Dr. Watson this morning
I am having a number of machines DR. Watson on NTPrime service this
morning. And it seems that the web site is down as well. Anyone
know what is happpening?
Alan
"A programmer is a person who turns coffee into software."
Alan R. Vidmar Assistant Director of IT
Office of Financial Aid University of Colorado
[EMAIL PROTECTED] (303)492-3598
*** This message printed with 100% recycled electrons ***
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------------------------------
Date: Wed, 26 Jul 2000 08:13:53 -0700
From: Bob Margulies <[EMAIL PROTECTED]>
Subject: Mersenne: Prime95 shutdown mystery.
I have just finished a case (M9836773) and expected Prime 95 (version
20.6, running under Win 98) to begin another. Instead I have the message
"This program has performed an illegal operation and will be shut down."
Under "Details" it reports exception 6d9H in module RPCRT4.DLL at
0187:7fb953e3. I have not been able to restart it.
Contents of worktodo.ini:
Test=10634683,64,1
Bottom lines of results.txt:
[Wed Jul 26 04:52:21 2000]
UID: rsm/Gateway_600, M9836773 is not prime. Res64: 53E109453BBD6E46.
WW1: 337F6E13,7631220,00000000
Contents of local.ini:
CPUType=10
CPUSpeed=600
ComputerID=Gateway_600
CPUHours=24
LastEndDatesSent=963943568
RollingStartTime=0
VacationEnd=0
VacationOn=1
SelfTest512Passed=1
RollingAverage=895
SelfTest640Passed=1
Obvious questions:
Did the results on M9836773 actually get reported?
How do I get restarted? Rebooting hasn't helped.
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------------------------------
Date: Wed, 26 Jul 2000 09:06:20 -0700
From: Stefan Struiker <[EMAIL PROTECTED]>
Subject: Mersenne: Compaq Presario 7998 Redux
Presarioers, et al:
On 07July00 I noted:
"On several Athlon machines, from 750MHz to 1000MHz, P95 takes
about the same number of clocks per iteration doing a factoring assignment,
in the present case 4.75 billion. The Compaq 7998 settles at 5.28 billion
for the same task, but can be driven down to 4.75 briefly by re-booting,
running ReCache, and then some start/stop/start shenanigans. Soon the number of
clocks starts to drift upward, and settles at 5.28/5.3 again"
Found and smushed __one__ die-hard parasitic process by renaming it:
bttnserver.exe
which executes even after a utility such as ProcessViewer2000 has tried
to kill it. Ordinarily 5 threads are spun for bttnserver, and only renaming
makes it vanish.
The result? About 100 million clocks saved per iteration!
Best Wishes,
Stefanovic
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------------------------------
Date: Wed, 26 Jul 2000 14:12:52 -0400
From: Bruce A Metcalf <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Prime95 shutdown mystery.
At 08:13 AM 7/26/00 -0700, Bob Margulies wrote:
>I have just finished a case (M9836773) and expected Prime 95 (version
>20.6, running under Win 98) to begin another. Instead I have the message
>"This program has performed an illegal operation and will be shut down."
>Under "Details" it reports exception 6d9H in module RPCRT4.DLL at
>0187:7fb953e3. I have not been able to restart it.
Oh goodie! So I'm *not* the only one.
My system just crashed the same way. Even a cold boot and reinstalling
from the prime95.zip file doesn't fix it. I've got a Pentium 150 running
Prime 95 ver. 20.6 under Windows 95. And advice will be most appreciated.
Bruce A. Metcalf
mailto:[EMAIL PROTECTED]
http://myweb.magicnet.net/bmetcalf
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------------------------------
Date: Wed, 26 Jul 2000 19:48:28 -0400
From: Nathan Russell <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Prime95 shutdown mystery.
Bruce A Metcalf wrote:
>
> At 08:13 AM 7/26/00 -0700, Bob Margulies wrote:
>
> >I have just finished a case (M9836773) and expected Prime 95 (version
> >20.6, running under Win 98) to begin another. Instead I have the message
> >"This program has performed an illegal operation and will be shut down."
> >Under "Details" it reports exception 6d9H in module RPCRT4.DLL at
> >0187:7fb953e3. I have not been able to restart it.
>
> My system just crashed the same way. Even a cold boot and reinstalling
> from the prime95.zip file doesn't fix it. I've got a Pentium 150 running
> Prime 95 ver. 20.6 under Windows 95. And advice will be most appreciated.
I believe there was a bug in 20.5 that crashed when doing trial
factoring after P-1 factoring on the same boot. 20.6 supposedly
eliminated that, but there might be something still wrong.
Nathan
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------------------------------
End of Mersenne Digest V1 #762
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