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-   -   Can you disable solver output? (https://www.cfd-online.com/Forums/openfoam-solving/129682-can-you-disable-solver-output.html)

vbchris February 10, 2014 16:33

Can you disable solver output?
 
Hi all,

I was wondering if anyone knows a way to disable solver output to the terminal or log file?
On the cluster I am using, the file system manager is the bottle neck in my simulation run times, write operations seem to hang when under load.
Therefore I want to write to the file system as infrequently as possible.
Since the code is writing time step files once every half hour or so I think this is mostly due to the solver output stream.

I though about > /dev/null but I think this still writes to the file system.

Any input is appreciated.


Thanks,

Chris

alexeym February 11, 2014 02:43

Hi,

You can do something like this:

Code:

mkdir -p $HOME/.OpenFOAM/$WM_PROJECT_VERSION
cp $WM_PROJECT_DIR/etc/controlDict $HOME/.OpenFOAM/$WM_PROJECT_VERSION/

Then edit debugSwitches dictionary in $HOME/.OpenFOAM/$WM_PROJECT_VERSION/controlDict and change lines

Code:

...
SolverPerformance  1;
...
lduMatrix          1;
...

to

Code:

...
SolverPerformance  0;
...
lduMatrix          0;
...

These ones switch off most of the output. If it's not enough there are other switches with values greater than 0, change them to 0 and solver can be made completely silent.

vbchris February 13, 2014 16:31

Thanks Alexey,

This is exactly what I was looking for.

In version 2.2.0

SolverPerformance 0;

doesn't exist but if other variables are set to 0 it will run quietly.

Chris

akidess February 14, 2014 04:27

Just for the sake of completeness: /dev/null does not write to the file system. It's a "special file" where the kernel reports a successful write but doesn't actually touch the disk at all. So it's pretty fast.

- Anton

Quote:

Originally Posted by vbchris (Post 474342)
Hi all,

I was wondering if anyone knows a way to disable solver output to the terminal or log file?
On the cluster I am using, the file system manager is the bottle neck in my simulation run times, write operations seem to hang when under load.
Therefore I want to write to the file system as infrequently as possible.
Since the code is writing time step files once every half hour or so I think this is mostly due to the solver output stream.

I though about > /dev/null but I think this still writes to the file system.

Any input is appreciated.


Thanks,

Chris



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