lanczos error: submatrix is not invertible
 

Just don't understand this error. LA was restarted after 3 days with a "lanczos error: submatrix is not invertible" whilst away from the machine. What's this about? Should I cancel this job and sieve more?


[CODE]Sat Dec 3 23:38:13 2016 commencing Lanczos iteration (8 threads)
Sat Dec 3 23:38:13 2016 memory use: 5457.8 MB
Sat Dec 3 23:39:30 2016 linear algebra at 0.0%, ETA 190h16m
Sat Dec 3 23:39:54 2016 checkpointing every 80000 dimensions
Wed Dec 7 16:54:36 2016 lanczos error: submatrix is not invertible
Wed Dec 7 16:54:36 2016 lanczos halted after 109172 iterations (dim = 6903580)
Wed Dec 7 16:54:36 2016 linear algebra failed; retrying...
Wed Dec 7 16:54:36 2016 commencing Lanczos iteration (8 threads)
Wed Dec 7 16:54:36 2016 memory use: 5457.8 MB
Wed Dec 7 16:55:52 2016 linear algebra at 0.0%, ETA 187h32m
Wed Dec 7 16:56:15 2016 checkpointing every 80000 dimensions[/CODE]


Edit: Didn't think about this error algebra related. I understand its concept. What should I do next, sieve more?

This error is memory related. Every time we saw it, it was due to memory ever so slightly faulty.

One thing to try is to rename *.bak.chk (if you were able to save it) to .chk and try to restart.

[QUOTE=Batalov;448681]This error is memory related. Every time we saw it, it was due to memory ever so slightly faulty.

One thing to try is to rename *.bak.chk (if you were able to save it) to .chk and try to restart.[/QUOTE]

Thank you. I've restarted it with the 3 pm GMT backup file. Let´s see what happens.

[QUOTE=Batalov;448681]This error is memory related. Every time we saw it, it was due to memory ever so slightly faulty.[/quote]

Bother, I got a great swathe of this error on my three-year-old i7-4930K machine over the last couple of days.

I have noticed that I see it more when running cudalucas, giving me a slight question as to whether it's a driver problem rather than a physical defect.

(that is, I was getting it once every five minutes, and after a reboot I've got it zero times in twelve hours)