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Old 2016-09-30, 15:42   #304
VBCurtis's Avatar
Feb 2005
Riverside, CA

52·11·17 Posts

Originally Posted by EdH View Post
Thank you, VBCurtis. I think I now have some understanding, but let's see if I've caught one thing correctly. The, "Adding these up," is referring to the percentages? In which case, the just over 1/3 is because 10% + 16% +9% = 35%? And, the efficiency is determined by how long it takes to run different B1 curves? Are you also saying that I should run a particular B1 to the t40 level and then move up to the next B1 for best efficiency?

I would like to see that analysis tool, if you happen to find it. (Or, if someone else knows where it is.)

The last questions (for now) would be to all:

How do we know if someone is running ECM on the current composite and what the total t-level may be across all work? Or, does it matter?
Nobody tracks how much ECM has been done on a number; that's why we announce plans/curves completed on the forum for publicly-interesting numbers.

Yes to adding the percentages. Usually, so few curves are done at a small level that the contribution of, say, B1=3M curves to a t50 is so small as to be ignored. In your case, you did so many that the percentage was worth noting.

My experiments toward minimizing time to find a factor of unknown size led me to run half the number of curves for a t-level before moving up to the next B1 size; I might run 500 at 1M before moving to 3M, instead of 900. Henry's experience with the bayesian tool suggests even less than that; both my heuristic and the bayesian tool fly in the face of RDS' published papers from the old days, which were the source of the traditional method.

To be clear, the traditional method is what you summarized: Complete curves at B1=3M sufficient for a t40 (according to help documentation or the -v flag of ECM), then move to 11M and run a number of curves equal to t45, etc.

I use "efficiency" to mean "best chance to find a factor per computron". I did a bunch of messing about with -v curve counts, k-values that determine B2 size, etc, and I think I gained a few percentage points of efficiency by using different B1 values than standard. The folks who actually know what they're doing like to remind us that the optimal settings are a very broad maximum, and it hardly matters what we choose so long as we don't use redundantly large numbers of curves with small B1.
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