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Old 2020-11-05, 23:01   #27
ryanp
 
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Jun 2012
Boulder, CO

27610 Posts
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Quote:
Originally Posted by bsquared View Post
Thanks, that's unexpected but neat. Wonder where the crossover is...
With larger inputs and B1's, the speedup is even more dramatic:

Code:
$ echo "2^2267-1" | ./ecm -c 5 43e6
GMP-ECM 7.0.4 [configured with GMP 6.2.0, --enable-asm-redc] [ECM]
Input number is 2^2267-1 (683 digits)
Using B1=43000000, B2=198654756318, polynomial Dickson(12), sigma=0:12068850290356100037
Step 1 took 546568ms
Step 2 took 163563ms
vs.

Code:
$ echo "2^2267-1" | ./ecm -c 5 43e6
GMP-ECM 7.0.4 [configured with GMP 6.2.0, GWNUM 29.8, --enable-asm-redc] [ECM]
Due to incompatible licenses, this binary file must not be distributed.
Input number is 2^2267-1 (683 digits)
Using B1=43000000, B2=198654756318, polynomial Dickson(12), sigma=0:16623107045151173302
Step 1 took 250555ms
Step 2 took 163852ms
Over twice as fast in B1!
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