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Old 2009-01-08, 05:28   #1
petrw1
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"Wayne"
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Default Not sure I should have this DC....

Code:
Exponent Status Data  
18728873 No factors below 2^67 
 P-1 B1=225000, B2=4500000 
 Unverified LL 46D44BAAF2DE42__ by "Ezram van Rijnberk" 
 Unverified LL 9FF61215444796__ by "Stefan Klinke" 
 Unverified LL FB879860A8D339__ by "petrw1" on 2008-12-21 
 Assigned Double-checking to "petrw1" on 2008-12-21 
 History FB879860A8D339__ by "petrw1" on 2008-12-21
Three LL's/DC's. Three different residues. That alone is a concern.

But, one DC was mine and it is back assigned to me to DC again. Should I release it?
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Old 2009-01-08, 10:37   #2
lycorn
 
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What is normally considered "good pratice" is to have, for a given exponent, the first time test and the DC perfomed by different participants.
So I would say "yes, release it".
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Old 2009-01-08, 12:58   #3
cheesehead
 
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The use, since several versions ago, of a pseudorandom bit-shift at the beginning (and reversal at the end) provides noticeable protection against faulty hardware's producing the same erroneous residue from the same cause during two successive L-Ls on the same system. So there is not quite the same suspicion of same-system results that there had been before. However, there are still sources of error that would not be affected by that bit-shift.

IIRC v4 reports showed that shift count along with the returned residue.

Last fiddled with by cheesehead on 2009-01-08 at 13:00
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Old 2009-01-08, 17:11   #4
petrw1
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Quote:
Originally Posted by cheesehead View Post
The use, since several versions ago, of a pseudorandom bit-shift at the beginning (and reversal at the end) provides noticeable protection against faulty hardware's producing the same erroneous residue from the same cause during two successive L-Ls on the same system. So there is not quite the same suspicion of same-system results that there had been before. However, there are still sources of error that would not be affected by that bit-shift.

IIRC v4 reports showed that shift count along with the returned residue.
So are you implying I should or should not drop it OR it doesn't really matter anymore?
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Old 2009-01-08, 17:40   #5
cheesehead
 
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Quote:
Originally Posted by petrw1 View Post
So are you implying I should or should not drop it OR it doesn't really matter anymore?
Be above suspicion, like Caesar's wife. (http://www.brainyquote.com/quotes/qu...aes161092.html)

Drop it like a hot potato.

Last fiddled with by cheesehead on 2009-01-08 at 17:47 Reason: Then ask yourself: What do potatoes have to do with GIMPS?
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Old 2009-01-08, 17:59   #6
petrw1
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Hereby dropped....
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Old 2009-01-08, 20:35   #7
S485122
 
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I searched the double-checked results for exponents above 40M. There where quite a lot double checked by the same user and sometimes the same computer. Some of the results are obviously multiple submissions of the same result... See the attached file.

Jacob
Attached Files
File Type: zip self confirmed results.zip (7.1 KB, 116 views)
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Old 2009-01-10, 16:21   #8
cheesehead
 
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Quote:
Originally Posted by S485122 View Post
quite a lot double checked by the same user and sometimes the same computer
Caesar would've ordered them to be DCed independently ... or else divorced them.
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Old 2009-01-11, 13:55   #9
lycorn
 
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And those exponents are lucky that Caesar was not like Henry VIII...
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