20220924, 20:24  #23 
P90 years forever!
Aug 2002
Yeehaw, FL
5·23·71 Posts 
Finally, nailed the bugger.
Starting in 30.7, the curve starting point is incorrectly computed on every curve after the first curve. This is due to "leftover state" from stage 2. The problem is lessened in 30.9 as often you'll see "switching back to FFTlen x" at the end of stage 2. I do not know how this bug impacts the success rate for ECM finding a factor. 
20220925, 02:09  #24 
P90 years forever!
Aug 2002
Yeehaw, FL
5×23×71 Posts 
Download 30.9 build 2 for a fix.

20220925, 11:19  #25 
Einyen
Dec 2003
Denmark
19×181 Posts 
Nice work!
Interesting that it could still find factors and even factors with group orders outside B1/B2. I guess the different starting points made the curves correspond to different B1/B2 values than was intended? This is just a guess. I do not really understand the math behind ECM in detail. 
20220925, 14:20  #26 
Dec 2021
54_{8} Posts 
It sounds more likely to me that the different starting points correspond to different sigma values, which change the B1/B2 required to find the factor. For any starting point, you can run the curve to any B1/B2 you want in a similar fashion to P1.

20221002, 19:24  #27 
P90 years forever!
Aug 2002
Yeehaw, FL
5·23·71 Posts 

20221008, 05:30  #28 
"特朗普trump"
Feb 2019
朱晓丹没人草
2^{2}·3·11 Posts 

20221008, 12:01  #29  
Apr 2020
929 Posts 
Quote:
ECM curves are determined by a random seed called the sigma value. The bug led to the incorrect sigma being displayed, so ECM was still being run, and was still just as likely to find a factor. Prime95 just wasn't running the exact curves it said it was running. 

20221010, 08:42  #30 
Romulan Interpreter
"name field"
Jun 2011
Thailand
3×23×149 Posts 

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