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Old 2020-06-16, 01:53   #9
EdH's Avatar
"Ed Hall"
Dec 2009
Adirondack Mtns

5·677 Posts

I think your larger crossover might explain the results of an experiment I've been conducting:

Two machines "virtually" identical.

Machine 1: Aliqueit running YAFU for qs, for ECM and CADO-NFS for GNFS

Machine 2: Aliqueit running option -y (YAFU for all)

Both were started on an existing sequence that was around 105 digits.

Although Machine 1 seemed to be doing a lot more ECM than Machine 2, it ran away, leaving machine 2 many lines behind. At this time, the sequence had taken a downturn and was shedding digits.

I swapped the setups and copied the longer sequence to Machine 2, so they would start even again. This time Machine 1, running YAFU (-y) ran away by over 30 indices, at first! As the digits rose again, Machine 2 caught up with and passed Machine 1, even though it had been 30 indices behind.

I will have to do some more comparisons to really conclude anything, but the preliminary shows CADO-NFS to be promising. As to my using CADO-NFS, for my Aliqueit runs, I'm implementing distributed polyselect and sieving across >20 machines of various architecture. I was able to do this with, too, but CADO-NFS is simpler and now it seems faster, also.

I noticed a query as to the possibility of YAFU using CADO-NFS and know this would be quite a bit of work, but from my playing around and other tests, etc., if you ever do consider CADO-NFS, I would suggest still letting Msieve do the LA.
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