mersenneforum.org  

Go Back   mersenneforum.org > Factoring Projects > Lone Mersenne Hunters

Reply
 
Thread Tools
Old 2021-01-21, 20:28   #1772
James Heinrich
 
James Heinrich's Avatar
 
"James Heinrich"
May 2004
ex-Northern Ontario

2·3·5·109 Posts
Default

Quote:
Originally Posted by storm5510 View Post
I too have found a 39-digit factor... I never checked on any list to see if it was there.
It's #385 on the biggest ECM factors (edit: of Mersenne numbers) list.

Last fiddled with by James Heinrich on 2021-01-22 at 13:26
James Heinrich is offline   Reply With Quote
Old 2021-01-22, 07:18   #1773
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

927510 Posts
Default

Quote:
Originally Posted by James Heinrich View Post
It's #385 on the biggest ECM factors list for mersenne numbers.
Fixed it for you. As opposite to biggest ever, openweight.
LaurV is offline   Reply With Quote
Old 2021-01-23, 18:15   #1774
Jwb52z
 
Jwb52z's Avatar
 
Sep 2002

5·157 Posts
Default

P-1 found a factor in stage #2, B1=737000, B2=19917000.
UID: Jwb52z/Clay, M102307399 has a factor: 376759813552401417250697953 (P-1, B1=737000, B2=19917000),

88.284 bits.
Jwb52z is offline   Reply With Quote
Old 2021-01-23, 18:20   #1775
storm5510
Random Account
 
storm5510's Avatar
 
"Norman D. Powell"
Aug 2009
Indiana, USA.

22×7×67 Posts
Default

Quote:
Originally Posted by James Heinrich View Post
It's #385 on the biggest ECM factors (edit: of Mersenne numbers) list.
Thank you for the link. 70 digits at the top. That is quite amazing.
storm5510 is offline   Reply With Quote
Old 2021-01-27, 02:58   #1776
Jwb52z
 
Jwb52z's Avatar
 
Sep 2002

11000100012 Posts
Default

P-1 found a factor in stage #2, B1=738000, B2=19926000.
UID: Jwb52z/Clay, M102357631 has a factor: 321965205924875189306321369 (P-1, B1=738000, B2=19926000),

88.057 bits.
Jwb52z is offline   Reply With Quote
Old 2021-01-27, 07:43   #1777
gLauss
 
Nov 2014

110002 Posts
Default

I found a very easy one (randomly selected a nice number and spent <1 GhzD effort) in M3331331 yesterday, but the number was factored previously: mersenne.ca, Primenet Details. What bothers me is that the same PRP residue is identical for the PRP test with 1 factor and the PRP test with 2 factors? This is a bug, isn't it?

The factor I'm most proud of is this lucky 118bit one in M70553939 which I found in normal LL/PRP testing.
gLauss is offline   Reply With Quote
Old 2021-01-27, 08:00   #1778
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

52×7×53 Posts
Default

Quote:
Originally Posted by gLauss View Post
This is a bug, isn't it?
Yep. Bug for sure, unless you used gpuowl, which totally ignores the factors, and does prp for the whole Mxx, in which case both residues (and the semantic result, like the cofactor being PRP or not) are wrong. Right now, only P95/mprime can be used for PRP-CF and PRP-CF-DC. If you use gpuowl, it will not signal an error, but it will PRP the wrong number. I assume Mihai is working on this, either to include the PRP-CF option, or to give and error when worktodo line contains factors.

Last fiddled with by LaurV on 2021-01-27 at 08:01
LaurV is offline   Reply With Quote
Old 2021-01-27, 08:16   #1779
gLauss
 
Nov 2014

2410 Posts
Default

Quote:
Originally Posted by LaurV View Post
Yep. Bug for sure,
I used mprime and the residue B786DF1732AE7343 is the one which mprime reported in the results.json.txt. I filed a bug in the Primenet section.
gLauss is offline   Reply With Quote
Old 2021-01-27, 08:46   #1780
axn
 
axn's Avatar
 
Jun 2003

23·607 Posts
Default

Quote:
Originally Posted by LaurV View Post
Yep. Bug for sure
No. P95 calculates 3^(Mp+1) == 3^(f+1) to prp test Mp/f. So the residue produced is always the same.

By calculating 3^(Mp+1), you can just do repeated squaring (more efficient), which also allows GEC / CERT capability.
axn is offline   Reply With Quote
Old 2021-01-27, 09:11   #1781
kruoli
 
kruoli's Avatar
 
"Oliver"
Sep 2017
Porta Westfalica, DE

22·109 Posts
Default

Quote:
Originally Posted by gLauss View Post
The factor I'm most proud of is this lucky 118bit one in M70553939 which I found in normal LL/PRP testing.
It looks like Brent-Suyama helped you there.
kruoli is online now   Reply With Quote
Old 2021-01-27, 16:46   #1782
James Heinrich
 
James Heinrich's Avatar
 
"James Heinrich"
May 2004
ex-Northern Ontario

2×3×5×109 Posts
Default

Quote:
Originally Posted by axn View Post
No. P95 calculates 3^(Mp+1) == 3^(f+1) to prp test Mp/f. So the residue produced is always the same.
By calculating 3^(Mp+1), you can just do repeated squaring (more efficient), which also allows GEC / CERT capability.
Does this mean one could fake the residue for a PRP test with a different number of cofactors (trivial, it's always the same), but one would not be able to (so easily) fake the proof?
James Heinrich is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
A new factor of F11?! siegert81 FermatSearch 2 2018-01-24 04:35
AMD goes inane jasong jasong 18 2013-11-15 22:54
A fond farewell rogue Lounge 10 2008-11-21 05:25
P56 ECM Factor wblipp Factoring 4 2005-04-23 11:41
Shortest time to complete a 2^67 trial factor (no factor) dsouza123 Software 12 2003-08-21 18:38

All times are UTC. The time now is 12:30.

Wed Mar 3 12:30:36 UTC 2021 up 90 days, 8:41, 0 users, load averages: 2.02, 2.20, 2.32

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.