View Single Post
Old 2020-08-21, 12:59   #10
RedGolpe
 
RedGolpe's Avatar
 
Aug 2006
Monza, Italy

22·17 Posts
Default

Summary of findings follows.

Tested factorization of the C107 54022122323205311359700529131254845253584832080092810873601245077747279904751944559089001546838958178759103 = 6892192422790360694669529583587636497846216763819494386433 * 7838162228984026472885414974266767581580262988991 on two machines with the following specifications:
- "EC2": an Amazon EC2 instance with 3.3 GHz AMD EPYC processors, 4 cores, 8 threads, 16 GiB RAM, Ubuntu 18.04 fully updated
- "WSL": a Windows 10 PC with Intel Core i7-7800X processors, 6 cores, 12 threads, 32 GiB RAM, WSL Ubuntu 18.04 fully updated

All tests were run with the default command line cado-nfs.py <N> workdir=<workdir> unless specified.
When they failed, all tests did with the same "corrupted table" error described here.
When failed, the error seems reproducible with the same command line on the same machine.
A log file is available.

Failed on EC2, CADO-NFS with timestamp July 22 (two runs).
Failed on EC2, CADO-NFS with timestamp August 18.
Failed on EC2, CADO-NFS with timestamp August 18, parameters -t 6.
Passed on WSL, CADO-NFS with timestamp March 17.
Failed on WSL, CADO-NFS with timestamp August 18.
Failed on WSL, CADO-NFS with timestamp August 18, parameters -t 8.

So it looks like whatever it is, it does not depend on the processor type, on the number of cores and on the actual cores used, and was introduced some time between March 17 and July 22. I will report this as a bug to the cado-nfs-discuss mailing list.

Last fiddled with by RedGolpe on 2020-08-21 at 13:42
RedGolpe is offline   Reply With Quote