Quote:
Originally Posted by VBCurtis
900 coreyears computation time (800 sieve, 100 matrix) on 2.1ghz Xeons gold. They observe this job ran 3x faster than would be expected from an extrapolation from RSA768, and in fact would have been 25% faster on identical hardware than RSA768 was.
I'd love a more detailed list of parameters! Perhaps a future CADO release will include them in the c240.params default file. :)
For comparison, we ran a C207 Cunningham number 2,2330L in about 60 coreyears sieve, which scales really roughly to an estimate of 3840 coreyears sieve (6 doublings at 5.5 digits per doubling). The CADO group found a *massive* improvement in sieve speed for large problems! 4 times faster, wowee.
Edit: Their job is so fast that RSA250 is easily within their reach. Which means that C251 from EuclidMullen is within reach, theoretically. I mean, imagine if all NFS work over 200 digits is suddenly twice as fast.....

Truly excellent work. And as you say doubling the speed adds 56 digits.
If going after a ~C250, I think 2,1139+ is a better target. It's been waiting for nearly
60 years to be factored. The EuclidMullen cofactor is a relative newcomer. Of course
I am biased towards Cunningham numbers.
I'd love to hear the implementation/parameterization details that resulted in their
terrific speed improvement.