mersenneforum.org  

Go Back   mersenneforum.org > Prime Search Projects > No Prime Left Behind

Reply
 
Thread Tools
Old 2012-02-21, 10:42   #1101
PCZ
 
PCZ's Avatar
 
Jun 2006
Chertsey Surrey UK

5468 Posts
Default

Here is the list of pairs
I will redo them and send you the results so you have the correct residues.
Attached Files
File Type: txt workfile.txt (18.1 KB, 68 views)

Last fiddled with by PCZ on 2012-02-21 at 11:39
PCZ is offline   Reply With Quote
Old 2012-02-21, 12:18   #1102
AMDave
 
AMDave's Avatar
 
Jan 2006
deep in a while-loop

2×7×47 Posts
Default

Tops. Saved to my desktop.
AMDave is offline   Reply With Quote
Old 2012-02-21, 19:42   #1103
mdettweiler
A Sunny Moo
 
mdettweiler's Avatar
 
Aug 2007
USA (GMT-5)

792 Posts
Default

Okay, I've deleted the two problem primes from the PRPnet server's database and re-inserted the respective candidates. They were promptly reassigned to two of Lennart's clients and should be returned within 10 minutes or so (composite, of course). I adjusted PRPnet's stats tallies appropriately as well. (Note: I adjusted the "primes found" counts for both PCZ and Free-DC but not the "tests performed" counts, since that would also involve messing with the points count and that would be a mess. Since he'll be re-testing the same candidates manually on a stable machine, the stats will still be accurate in the end.)

As for the rest of the candidates tested by PCZ's unstable machine, those would be a bit more tricky to delete; I deleted the two primes from the PRPnet database individually, i.e. by typing in each candidate name specifically. This, of course, would be impractical for a long list of candidates; and it isn't really necessary anyway since we're re-doing them manually, not through the PRPnet server.

Since the re-dos for the bad results will be done by the same user as before, fixing them in the main stats database should be fairly easy--once he completes the tests, we run a diff to compare the old and new results, and whichever residuals are different we fix with:
update results set residual=[new] where k=[k] and n=[n];
respectively for each corrected residual--a MySQL script file with commands in the above format should be easy enough to whip up by a Perl script or the like. The end result will be that nothing changes except the residuals are now correct.

The only thing this doesn't take into account is the raw text results files from which the DB initially loaded the results--those will still have the incorrect residuals in them. This isn't too big a deal since they'll already be fixed in the DB, but if we did ever have to reload the entire DB from the results files (say, if it was somehow lost), we'd end up with the incorrect residuals. Dave, how do you think we should handle this?

Last fiddled with by mdettweiler on 2012-02-21 at 19:42
mdettweiler is offline   Reply With Quote
Old 2012-02-21, 22:09   #1104
henryzz
Just call me Henry
 
henryzz's Avatar
 
"David"
Sep 2007
Cambridge (GMT/BST)

131618 Posts
Default

Might be worth seeing if other results from the machine are affected before giving it too much thought. It is incredibly unlikely that two composite numbers would be found to be prime just from random residues.
henryzz is offline   Reply With Quote
Old 2012-02-22, 06:12   #1105
mdettweiler
A Sunny Moo
 
mdettweiler's Avatar
 
Aug 2007
USA (GMT-5)

792 Posts
Default

Quote:
Originally Posted by henryzz View Post
Might be worth seeing if other results from the machine are affected before giving it too much thought. It is incredibly unlikely that two composite numbers would be found to be prime just from random residues.
Yes, but I'm not sure if random residues are the sole factor in creating false-positive results; while I will admit I don't have any mathematical basis for such a claim, empirically, there are a lot of false primes that have been turned up over time, far more than would be expected if it was just a random 0 residue. (There's a thread at CRUS from a while back where we calculated how many tests it would take to crank out a random composite residue containing a 9-hexdigit string, and it was quite huge.) False primes seem to be a (somewhat) common type of bad result produced by unstable machines, so I'm thinking there must be something more to it that can "bias" the incorrect result toward positive in certain types of instability situations.

Last fiddled with by mdettweiler on 2012-02-22 at 06:12 Reason: punctuation
mdettweiler is offline   Reply With Quote
Old 2012-02-22, 11:13   #1106
AMDave
 
AMDave's Avatar
 
Jan 2006
deep in a while-loop

2·7·47 Posts
Default

Quote:
Originally Posted by mdettweiler View Post
Dave, how do you think we should handle this?
I can pull them from the files, no problems, but I think we should see what results PCZ comes back with from the other machine before I make permanent changes to the results files.

Last fiddled with by AMDave on 2012-02-22 at 11:15
AMDave is offline   Reply With Quote
Old 2012-02-22, 11:29   #1107
pinhodecarlos
 
pinhodecarlos's Avatar
 
"Carlos Pinho"
Oct 2011
Milton Keynes, UK

3·37·43 Posts
Default

I think the NPLB server should automatically verify the primes found. If it is confirmed as prime then nothing happens, if it is confirmed as composite then the pair should go into the server to be tested again.
pinhodecarlos is online now   Reply With Quote
Old 2012-02-22, 11:51   #1108
PCZ
 
PCZ's Avatar
 
Jun 2006
Chertsey Surrey UK

2×179 Posts
Default

Quote:
Originally Posted by AMDave View Post
I can pull them from the files, no problems, but I think we should see what results PCZ comes back with from the other machine before I make permanent changes to the results files.
Wait for my results to come back.

Could be that there were only the two false positives and the rest of the tests were OK.

Haven't finished quite yet, but so far it doesn't look too bad.
Another 12 hrs or so and they will be finished and the residues can be compared.
PCZ is offline   Reply With Quote
Old 2012-02-22, 17:09   #1109
Lumiukko
 
Mar 2011
Finland

19 Posts
Default

Added 104945 : 741*2^1027639-1 (309354 digits) is prime.

--
Lumiukko
Lumiukko is offline   Reply With Quote
Old 2012-02-23, 00:03   #1110
Lennart
 
Lennart's Avatar
 
"Lennart"
Jun 2007

25·5·7 Posts
Default

Added 104956 : 727*2^1031225-1 (310433 digits)isPrime

Lennart
Lennart is offline   Reply With Quote
Old 2012-02-23, 06:31   #1111
odicin
 
Sep 2011
Potsdam, Germany

24×7 Posts
Default

Added 104966 : 703*2^1031219-1 (310431 digits) is prime.

Odi

Last fiddled with by odicin on 2012-02-23 at 06:31
odicin is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Report top-5000 primes here gd_barnes Conjectures 'R Us 880 2020-11-25 11:34
Report top-5000 primes for k=1003-3000 gd_barnes No Prime Left Behind 688 2020-04-24 07:31
All top 5000 primes will have the same number of digits in 2014 ;-) Batalov Conjectures 'R Us 10 2013-03-29 01:29
Twenty Oldest Primes on Top 5000 List masser Lounge 9 2008-08-27 12:31
get all the 5000 biggest primes above 100K digits jasong jasong 1 2007-06-09 22:51

All times are UTC. The time now is 23:09.

Wed Nov 25 23:09:16 UTC 2020 up 76 days, 20:20, 3 users, load averages: 1.04, 1.27, 1.33

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, 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.