Mersenne Digest Friday, August 1 2003 Volume 01 : Number 1083
----------------------------------------------------------------------
Date: Sat, 26 Jul 2003 11:20:34 +0100
From: "Doug Feather" <[EMAIL PROTECTED]>
Subject: Mersenne: Should I switch an exponent to another processor type?
I've currently got an exponent of the order of 20.05M running on a P4
(1.8Mhz). It has decided to run it with FFT size 1280K. It's done just
over 1M iterations (and hasn't finished Stage 2 P-1 since this only runs for
a few hours each night). If I'd of know that it was going to use this FFT
size before it started, it would have been better for me to switch it to
another processor type - since then it would have used a smaller FFT size.
If I now move the saved file to another processor type would it use a
smaller FFT size or is the FFT size hard coded into the save file or is this
a bad idea to move the saved file for other reasons?
While on the subject of FFT size where is the information stored about
which FFT size tests have been run on each machine? I ask because if this
is on the server then it would be a bad idea to reuse machine names.
Further if you upgrade Prime95 is it a good idea to get it to rerun the
tests again?
Doug.
_________________________________________________________________________
Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm
Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
------------------------------
Date: Sat, 26 Jul 2003 21:44:41 -0400
From: George Woltman <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Should I switch an exponent to another processor type?
At 11:20 AM 7/26/2003 +0100, Doug Feather wrote:
> I've currently got an exponent of the order of 20.05M running on a P4
>(1.8Mhz). It has decided to run it with FFT size 1280K. It's done just
>over 1M iterations (and hasn't finished Stage 2 P-1 since this only runs for
>a few hours each night). If I'd of know that it was going to use this FFT
>size before it started, it would have been better for me to switch it to
>another processor type - since then it would have used a smaller FFT size.
>If I now move the saved file to another processor type would it use a
>smaller FFT size or is the FFT size hard coded into the save file or is this
>a bad idea to move the saved file for other reasons?
I think you can move it to another machine without problem. The FFT size
is encoded in the save file, but when the save file is opened prime95 checks
to see if a different FFT length should be used and converts if necessary.
The only downside to moving an exponent is that if *either* computer has
hardware problems, then your result could be corrupted.
You could also look in undoc.txt for options on making prime95 choose FFT
crossover points more aggressively. Look in results.txt for info on how close
prime95 was to choosing the 1024K FFT length. If it was a really close call
you could edit local.ini to make it choose the 1024k FFT length for that
exponent.
>While on the subject of FFT size where is the information stored about
>which FFT size tests have been run on each machine?
This information is not recorded anywhere - my database does not care
which FFT length was used on each LL result.
_________________________________________________________________________
Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm
Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
------------------------------
Date: Fri, 01 Aug 2003 01:32:33 -0700
From: Eric Hahn <[EMAIL PROTECTED]>
Subject: Mersenne: Computing meltdown???
It appears that the message forwarding service is still down...
and that v22 seems to have a problem in dial-up connections...
attempting to force a dial-up and connnect to PrimeNet and
after a great deal of time... finally erroring out... instead
of checking to see if there is a connection present before
attempting to communicate... and if not... waiting... and
checking back later... to communicate when there is...
Closely examining the Assignment Report... I've noticed
that... mostly due to the message forwarding service being
down... but also maybe a little from the v22 problem... only
approximately 37% of assignments have been updated within
the last **5** (FIVE) weeks... This is in comparison to
the > 90% updates for the same period... over the last
year...
Are we going to have a major computing power meltdown???
Perhaps in the number of PCs using the client... or users
continuing to work on the project??? 1/3 of the current
computing power is still a lot of computing power... but
a major... and significannt drop...
Eric
_________________________________________________________________________
Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm
Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
------------------------------
End of Mersenne Digest V1 #1083
*******************************
