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Run time is OK but now I only get "Computation error"
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Questions and Answers : Unix/Linux : Run time is OK but now I only get "Computation error"

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el_gallo_azul
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Message 50671 - Posted: 29 Oct 2014, 20:58:31 UTC

CPDN was running successfully on my computer until 2014-10-24.

I moved BOINC's data directory from my SSD to my HDD a few days ago. I started this process first thing on 2014-10-25, and finished the process on 2014-10-28.

That appeared to have been successful, with new tasks downloading, running until complete, and then uploading.

However, it's been running in that configuration for a couple of days now, and all of the CPDN tasks that I have completed have given a "Computation error".

I had seen computation errors on CPDN previously, before I had installed all the correct libraries etc, but they usually happened at a run time of 0:00:00 (or very close to it). Now the tasks are running for a reasonable amount of time of around 40,000 seconds, and then they only give "Computation error" at the end of that time.

...Hmm that's interesting. I just looked at an example of a work unit for which I had had a "Computation error", and it looks like all of its tasks have had errors on a variety of computers with different operating systems.

Les Bayliss
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Message 50672 - Posted: 29 Oct 2014, 21:44:01 UTC - in response to Message 50671.

These problems are talked about in 2 threads in number crunching:

HadCM3 short - errors galore

hadcm3n Full Res Ocean out of memory error

Out of memory is "stack memory".
These matters are being looked at by the project people.


el_gallo_azul
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Message 50674 - Posted: 29 Oct 2014, 22:06:52 UTC - in response to Message 50672.

OK thanks.

I think my best course of action is to let it continue running and see what happens.

In theory, the 32GB of RAM that I have should easily be enough.

Just out of interest: Would CPDN (or indeed BOINC) benefit in any way if I installed more?

Les Bayliss
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Message 50680 - Posted: 29 Oct 2014, 23:57:17 UTC - in response to Message 50674.

"stack memory" is a small area of ram that's used by the processor for temporary storage of variable data. I think that the size is OS dependent. Also, it's only a few megs. Or used to be.

BOINC doesn't do much, or need much memory. It's sort of a combination "information desk" and "traffic controller".

Climate models are "reasonably" happy with 1 gig of ram each.

(Historical note:
Years ago, one of the UK universities was working on a high-res climate model that would need about 4.5 Gigs of ram per model. Unfortunately we lost our contact person before it got far, so I don't know what happened with it.
But it would have been interesting.)

el_gallo_azul
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Message 50683 - Posted: 30 Oct 2014, 3:14:28 UTC - in response to Message 50680.

OK thanks Les.

My other BOINC projects seem to be working OK (ie. running and then uploading results successfully) since the changes that I made, so I'll just leave it to run. Hopefully CPDN will also come good.

el_gallo_azul
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Message 50687 - Posted: 30 Oct 2014, 9:52:02 UTC
Last modified: 30 Oct 2014, 9:52:36 UTC

A couple of completed tasks are showing now. Hopefully we're back on track. I'll mark this one 'answered'.

Questions and Answers : Unix/Linux : Run time is OK but now I only get "Computation error"


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