[MITgcm-devel] Monitor and mnc/netcdf

[Ed Hill]

On Tue, 2004-07-13 at 11:04, Alistair Adcroft wrote:
> I was about to try MNCing the monitor output but ...
> 
>  MNC output is tiled.
>  Monitor output is single scalar and so most naturally should be in one
> output file.
>  We could have the same data written into multiple files aka MNC
>  or we could just let process number 0 write the monitor output aka
> _MASTER_THID().
> 
> Thoughts anyone?


Hi Alistair,

Been there, done that!  ;-)

Seriously, at JMC's prompting I added the ability for monitor to output
through mnc a while ago.  The few lines of code are in:

  mon_out.F  monitor.F  mon_init.F

and they're currently only producing files for the (mpiMyId .EQ. 0) case
so it effectively isn't tiled output (or, it only produces the zeroth
tile).

Is that acceptable?

Also, I've noticed that using mnc for the monitor output can slow things
down a bit.  Its not surprising that file IO through mnc/NetCDF is more
expensive than the plain-old STDIO output stream--its not really a fair
comparison.  But if necessary I can probably make mnc quicker for cases
such as the monitor output where we're frequently writing a handful of
scalar values to a single file.

Ed

-- 
Edward H. Hill III, PhD
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