mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Data

Reply
 
Thread Tools
Old 2016-04-04, 23:08   #1
ixfd64
Bemusing Prompter
 
ixfd64's Avatar
 
"Danny"
Dec 2002
California

32×269 Posts
Default "Verified" bad results?

Have a look at M1373881: http://mersenne.org/M1373881

The first LL result appears to be wrong but is still marked as verified. What gives?

Last fiddled with by ixfd64 on 2018-04-23 at 16:19
ixfd64 is offline   Reply With Quote
Old 2016-04-05, 01:10   #2
Prime95
P90 years forever!
 
Prime95's Avatar
 
Aug 2002
Yeehaw, FL

32×853 Posts
Default

Quote:
Originally Posted by ixfd64 View Post
Have a look at M1373881: http://mersenne.org/M1373881

The first LL result appears to be wrong but is still marked as verified. What gives?
Myrman ran his own program which had some bugs in printing the residue. His residues were granted a little extra leniency.
Prime95 is online now   Reply With Quote
Old 2016-04-05, 18:11   #3
bloodIce
 
bloodIce's Avatar
 
Feb 2010
Sweden

173 Posts
Default

I think that after noticing a discrepancy one should always attempt factoring. In this case it was easy to find a factor: 39615513750093690993572647. Does not solve the problem with the misreported residue, but it is clear that the number is composite if a factor is found.
bloodIce is offline   Reply With Quote
Old 2016-04-05, 21:12   #4
Madpoo
Serpentine Vermin Jar
 
Madpoo's Avatar
 
Jul 2014

31·107 Posts
Default

Quote:
Originally Posted by Prime95 View Post
Myrman ran his own program which had some bugs in printing the residue. His residues were granted a little extra leniency.
Those Myrman residues caused me to do some workarounds when I was analyzing the smaller exponents. LOL

In this case, and some others, I ran my own test just to confirm, since they were kind of weird. I wanted to make sure they really matched even though George was aware the residue was calculated a little differently but still matched, in theory. There shouldn't be any problems with the Myrman results at this point, I never found anything off kilter.
Madpoo is offline   Reply With Quote
Old 2016-04-06, 01:14   #5
Mark Rose
 
Mark Rose's Avatar
 
"/X\(‘-‘)/X\"
Jan 2013

B6B16 Posts
Default

I suppose it's kind of evil, but you could overwrite the bad-but-correct residues with the proper residues.
Mark Rose is offline   Reply With Quote
Old 2016-04-06, 05:19   #6
0PolarBearsHere
 
0PolarBearsHere's Avatar
 
Oct 2015

2×7×19 Posts
Default

I'd be interested to know what the difference in residue calculation is.
If it's going to become more widespread and we are likely to see more of them, it'd be good to have some indication of which residues are which type, so we know if a mismatch is actually a mismatch, or a match in a halloween outfit.
0PolarBearsHere is offline   Reply With Quote
Old 2016-04-06, 10:27   #7
S485122
 
S485122's Avatar
 
"Jacob"
Sep 2006
Brussels, Belgium

1,753 Posts
Default

Quote:
Originally Posted by 0PolarBearsHere View Post
If it's going to become more widespread and we are likely to see more of them...
This is old stuff, look at the exponent :
Quote:
Originally Posted by ixfd64 View Post
Have a look at M1373881: http://mersenne.org/M1373881
Also note the tense George used : ran not runs and had not has.
Quote:
Originally Posted by Prime95 View Post
Myrman ran his own program which had some bugs in printing the residue.
Jacob
S485122 is offline   Reply With Quote
Old 2016-04-06, 19:59   #8
Madpoo
Serpentine Vermin Jar
 
Madpoo's Avatar
 
Jul 2014

31·107 Posts
Default

Quote:
Originally Posted by S485122 View Post
This is old stuff, look at the exponent...
Yes, those results from that user are all quite old and no longer a concern.
Madpoo is offline   Reply With Quote
Old 2016-04-08, 00:07   #9
0PolarBearsHere
 
0PolarBearsHere's Avatar
 
Oct 2015

2·7·19 Posts
Default

Quote:
Originally Posted by Madpoo View Post
Yes, those results from that user are all quite old and no longer a concern.
Is it likely/possible that similar issues will be appear in the future, or will it be a case of "if you write your own software make sure your residues are going to match".
0PolarBearsHere is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Checking your "bad results" status is important Madpoo Hardware 4 2015-05-15 23:25
what's the point of "Iterations between results file outputs"? ixfd64 Software 3 2012-08-01 18:55
request: always include "from" in trial-factoring results James Heinrich Software 1 2005-04-10 02:44
Would Minimizing "iterations between results file" may reveal "is not prime" earlier? nitai1999 Software 7 2004-08-26 18:12
"Factoring only" results / stats in account details page schneelocke PrimeNet 3 2004-01-07 22:12

All times are UTC. The time now is 16:07.


Tue Nov 30 16:07:17 UTC 2021 up 130 days, 10:36, 0 users, load averages: 1.35, 1.56, 1.51

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, 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.