mersenneforum.org lanczos error: submatrix is not invertible
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 2016-12-07, 17:53 #1 pinhodecarlos     "Carlos Pinho" Oct 2011 Milton Keynes, UK 3·1,663 Posts 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 Edit: Didn't think about this error algebra related. I understand its concept. What should I do next, sieve more? Attached Thumbnails   Last fiddled with by pinhodecarlos on 2016-12-07 at 18:21
 2016-12-07, 18:50 #2 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 3×5×641 Posts 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.
2016-12-07, 19:05   #3
pinhodecarlos

"Carlos Pinho"
Oct 2011
Milton Keynes, UK

3·1,663 Posts

Quote:
 Originally Posted by Batalov 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.
Thank you. I've restarted it with the 3 pm GMT backup file. Let´s see what happens.

Last fiddled with by pinhodecarlos on 2016-12-07 at 19:32

2016-12-10, 10:40   #4
fivemack
(loop (#_fork))

Feb 2006
Cambridge, England

22×32×179 Posts

Quote:
 Originally Posted by Batalov This error is memory related. Every time we saw it, it was due to memory ever so slightly faulty.
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)

Last fiddled with by fivemack on 2016-12-10 at 22:58

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