ecm6 -dickson 12 -k 2 -n -one -redc -v -resume input_6262005.txt >>ECM6_output1.txt 1 43000000-150000000000
is the command I just finished running on 55 curves that I completed in Prime95 with B1 = 43000000
I'm wondering if ecm is smart enough to choose the -redc flag, as the README outlines,
Or perhaps for this k/n pair, -mpzmod would be the most appropriate? I'm not sure. Perhaps someone here with more mathematics experience can help me8. How to get the best of GMP-ECM?
Choice of modular multiplication. The ecm program may choose between 4 kinds
of modular arithmetic:
(1) Montgomery's REDC algorithm at the word level (option -modmuln).
It is quite fast for small numbers, but has quadratic asymptotic
complexity.
(2) classical GMP arithmetic (option -mpzmod).
Has some overhead with respect to (1) for small sizes, but wins
over (1) for larger sizes since it has quasi-linear asymptotic
complexity.
(3) Montgomery's REDC algorithm at high level (option -redc).
This essentially replaces each division by two multiplications.
Slower than (1) and (2) for small inputs, but better for large
or very large inputs.
(4) base-2 arithmetic for numbers dividing 2^n+1 or 2^n-1.
Each division has only linear time, but the multiplication are
more expensive since they are done on larger numbers.
I've attached a copy of my log file for the run above. In order to properly coordinate this effort, do we all need to just report 'Hey, I did x amount of curves on it with B1= 43..." etc.? Then when the sum of those curves is 7771 or so, we'll move on to some new settings?
I chose a pretty large B2 value - was this incorrect? I've always seen B2=B1*100, but JoeO you chose this really large value. Shouldn't it be within that B1-100*B1 range or something, as it will only work if and only if a single factor is between B1 and B2?
Reply With Quote