20090804, 23:30  #1 
Aug 2006
3·1,993 Posts 
Linear algebra at 600%
This seems wrong to me:
Code:
linear algebra completed 764732 of 125729 dimensions (608.2%, ETA 1027h56m) 
20090804, 23:55  #2  
Nov 2003
2^{2}×5×373 Posts 
Quote:
subspaces is not orthogonal. Indeed, it probably does not even span the subspace. 

20090805, 00:13  #3 
Tribal Bullet
Oct 2004
3·1,181 Posts 
You should restart the linear algebra from scratch. v1.42 has an orthogonality check that runs at regular intervals during the linear algebra, but the matrix has to be of size > 1M for checking to be turned on. I figured that was a good compromise because checkpointing is turned on at that size too, so that you can actually hope to restart from some point beyond the beginning when an error is detected.
Note that in the past, the occurrence of this error has brought the stability of the machine into question. Is your machine overclocked at all? 
20090805, 00:39  #4 
Mar 2008
5×11 Posts 
If not, I would recommend getting a CD with memtest and letting it run for a while. I was having the same problems, and found it was a faulty DIMM. Of course, that has taken my system from 3GB to 1GB, which is probably limiting my matrix sizes, but..

20090805, 00:58  #5 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
22740_{8} Posts 
The new orthogonality checks + restarts (see below*) will work very well on a slightly compromised computer. (A severely, irresponsibly OC'd computer will not be helped, though.) If errors happen only once/twice a day  you will do fine.
In a way, I have a computer like that, not because of OC'ing but because with 8Gb of memory [which I need, the numbers I am dealing with are that big] doesn't work completely flawlessly with the memory controller and whatnot. For control purposes, 4Gb works excellent for days through: with mprime or with msieve. 8Gb, however, and an error or a couple per day  at the hottest time of the day, of course. No errors at night. I have loosened memory timings to 566 (even though it is rated 555, 1066) and upped the NB voltages just a tad. The tuning is ongoing, but the calculation simply goes forward. Finished a couple in this regime already. Summer!! It's going to get cooler soon. ___________ *a simple perl script, feel free to make it better: Code:
#!/usr/bin/perl w $ret = 1; while($ret && e "t.dat.chk") { $cmd = "./msieve s t.dat i t.ini l ggnfs.log v nf t.fb t 4 ncr"; $ret = system($cmd); } 1; Last fiddled with by Batalov on 20090805 at 01:03 
20090805, 03:54  #6  
Aug 2006
3·1,993 Posts 
Quote:
Code:
charles@zed:~/mth/msieve1.41$ ./msieve sieving complete, commencing postprocessing linear algebra completed 2025 of 125729 dimensions (1.6%, ETA 0h 2m) linear algebra completed 2014 of 125729 dimensions (1.6%, ETA 0h 2m) linear algebra completed 10121 of 125729 dimensions (8.0%, ETA 0h 1m) linear algebra completed 4055 of 125729 dimensions (3.2%, ETA 0h 2m) linear algebra completed 4048 of 125729 dimensions (3.2%, ETA 0h 2m) linear algebra completed 8079 of 125729 dimensions (6.4%, ETA 0h 1m) linear algebra completed 14163 of 125729 dimensions (11.3%, ETA 0h 1m) linear algebra completed 6072 of 125729 dimensions (4.8%, ETA 0h 1m) linear algebra completed 20254 of 125729 dimensions (16.1%, ETA 0h 1m) linear algebra completed 6080 of 125729 dimensions (4.8%, ETA 0h 1m) linear algebra completed 6072 of 125729 dimensions (4.8%, ETA 0h 1m) linear algebra completed 2022 of 125729 dimensions (1.6%, ETA 0h 1m) linear algebra completed 4046 of 125729 dimensions (3.2%, ETA 0h 1m) linear algebra completed 2025 of 125729 dimensions (1.6%, ETA 0h 2m) linear algebra completed 4045 of 125729 dimensions (3.2%, ETA 0h 1m) linear algebra completed 2021 of 125729 dimensions (1.6%, ETA 0h 2m) linear algebra completed 18212 of 125729 dimensions (14.5%, ETA 0h 1m) linear algebra completed 16177 of 125729 dimensions (12.9%, ETA 0h 1m) linear algebra completed 6064 of 125729 dimensions (4.8%, ETA 0h 1m) linear algebra completed 18207 of 125729 dimensions (14.5%, ETA 0h 1m) linear algebra completed 14162 of 125729 dimensions (11.3%, ETA 0h 1m) linear algebra completed 10112 of 125729 dimensions (8.0%, ETA 0h 1m) linear algebra completed 10109 of 125729 dimensions (8.0%, ETA 0h 1m) linear algebra completed 2025 of 125729 dimensions (1.6%, ETA 0h 2m) linear algebra completed 4048 of 125729 dimensions (3.2%, ETA 0h 2m) linear algebra completed 8093 of 125729 dimensions (6.4%, ETA 0h 1m) linear algebra completed 6072 of 125729 dimensions (4.8%, ETA 0h 1m) linear algebra completed 6068 of 125729 dimensions (4.8%, ETA 0h 1m) linear algebra completed 6072 of 125729 dimensions (4.8%, ETA 0h 1m) linear algebra completed 2023 of 125729 dimensions (1.6%, ETA 0h 1m) Last fiddled with by CRGreathouse on 20090805 at 04:02 

20090805, 04:20  #7 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
2^{5}×3×101 Posts 
The easiest thing to try without rebooting is the "mprime m", and then invoke torture test option.

20090805, 04:41  #8 
Aug 2006
3·1,993 Posts 
I rebooted into memtest, and it looks like my (not that new) RAM is bad. I pulled out the offending sticks and am retrying. Edit: It worked just fine  it seems only the memory was an issue. I guess it makes sense that it took until the linear algebra phase to notice this.
Hmm, I guess it's time to look up Corsair's warranty information. I bought it 45 weeks ago, do you think they'll replace it? Last fiddled with by CRGreathouse on 20090805 at 04:45 
20090805, 07:25  #9 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
2^{5}×3×101 Posts 
They should.
Patriot did  for a 2x2Gb, when I got the same effect as you. Usually they will not crossmail, of course. And do start the formal RMA process. (My trick of getting a particular contact person's email off of the Patriot forum was effective. Some other people who write to the generic RMA email boxes usually complain that there's no answer for a while.) ____ Your avatar reminds me of my original avatar and a quote to go with it: "The Eagle never lost so much time as when he submitted to learn from the Crow." /W.B./ Last fiddled with by Batalov on 20090805 at 07:31 
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