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Old   February 12, 2014, 06:22
Question Elapsed Wall Clock Time
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Hi,

Is there a way to tell CFX to stop the simulation after 11 hours of wall clock run time? I submit jobs to a high end computer node, which the maximum allowed run time is 12 hours. Before the computer kicks me out and aborts my job I want to write a results file at the 11th hour.

I thought the "Elapsed Wall Clock Time Control" option might have done this but after reading the CFX Pre guide it seems I'm wrong.

I did a search, and read a comment by ghorrocks in this thread who said
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Originally Posted by ghorrocks View Post
Another thing to consider - you can use the cfx5stop command to stop a run in progress. It will shut down the slover and write a complete results file of whereever it got to. If you want to be clever you can set up a timed job (maybe using cron) to execute cfx5stop just before your time is up. Make sure you give it enough time to complete the timestep it is working on and write the results file.
This sounds like what I want. Does anyone know of a way to implement this?

Thank you
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Old   February 12, 2014, 06:28
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I had the same problem a few years ago and as far as I remember, the elapsed wall clock time control was exactly what I needed.
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Old   February 12, 2014, 06:35
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I've had problems getting the elapsed wall clock time control to work, especially if Im using many cores for the simulation. It seems that it never kicks in, even though the wall clock time has expired. If I have to stop a simulation, I just run cfx5stop manually. Im sure there are ways to do it more efficiently, e.g. using cron as mentioned by Glenn.
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Old   February 12, 2014, 06:37
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The elapsed wall clock time is a new(ish) feature which makes it very easy. The alternative using a cron job is the old way of doing it - but the idea of running cfx5stop to stop a job is also useful with other triggers which are not built into CFX.

As for how to use cron: http://www.lmgtfy.com/?q=cron (sorry about the sarcasm but I have been itching to use that link )
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Old   February 12, 2014, 07:02
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Excellent. Thanks for your replies. I'll do a bit more digging around using cron, and I'll run a few simple jobs using the command to see if it works.

P.S - Lance. I agree. I've had no luck getting the lapsed wall clock time control to work on 16 cores. I doubt it'll work when I ratchet up the power to 64 or 128 cores!
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Old   February 12, 2014, 07:57
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Quote:
Originally Posted by RicochetJ View Post
P.S - Lance. I agree. I've had no luck getting the lapsed wall clock time control to work on 16 cores. I doubt it'll work when I ratchet up the power to 64 or 128 cores!
If I remember correctly I got the control to work using 64 cores, but there was no way that it worked for 128 or more. However, cfx5stop worked fine for the same simulation. I asked Ansys about this a long time ago, but they never addressed the issue.
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