20220924, 20:24  #23 
P90 years forever!
Aug 2002
Yeehaw, FL
8,039 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
8,039 Posts 
Download 30.9 build 2 for a fix.

20220925, 11:19  #25 
Einyen
Dec 2003
Denmark
D3B_{16} 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
5^{2} 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
8039_{10} Posts 

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