[MITgcm-support] Restarting the MITgcm

[Uli Riemenschneider]

Hi Martin,

thanks for the reply. I followed your instructions, but somehow it is 
still not working. In file STDERR.0003 I find the following error message:

(PID.TID 0003.0001) *** ERROR *** MDSREADFIELD: File does not exist

I am not even sure what file it is referring too here? Any idea?
I am running the model on multiple processors, does that make a 
difference to the restart procedure?

Thanks for the help!
Ciao
Uli

Martin Losch wrote:
> Uli,
> 
> there are two run-time flags in data namelist PARM03:
> chkptFreq and pChkptFreq, the latter sets the frequency for permanent 
> checkpoint/restart files (they have the correct time step number already 
> in their file name), the former the frequency for the rolling 
> checkpoint/restart files (with ckptA,ckptB in their names).
> 
> The rolling checkpoints files alternatively are overwritten at a new 
> checkpoint. So if your chkptFreq = 5h, then after 5h 
> pickup.ckptA.001.001.data/meta are written, after 10h 
> pickup.ckptB.001.001.data/meta, and after 15h ckptA is overwritten, then 
> after 20h ckptB is overwritten, etc. That means that ckptA is NOT always 
> the latest checkpoint file, only half of the time (Dear code czars, I 
> hope that this is correct).
> 
>  If you want to restart from, say, ckptA, you have to rename 
> pickup.ckptA.001.001.data to pickup.0000004800.001.001.data (don't 
> forget the *.data) and set iter0 or starttime appropriately, as you have 
> done. In case there are some other pickup_*.ckptA.001.001.data files, 
> they have to be renamed, too.
> 
> I would however recommend for the future, that if you know for how long 
> you can and want to run your experiement and from where you want to 
> restart it, set
> chkptFreq=0.0, (to turn off rolling checkpoints)
> pChkptFreq=whatever this time is in seconds (for permanent checkpoint 
> files)
> 
> If you still have problems, have a look at the standard-output and this 
> will tell you which restart files are not found (just to make sure that 
> this is not the problem: for the restart you'll also need all data files 
> that you used for the run that lead to the restart file).
> 
> Hope this helps,
> 
> Martin
> 
> 
>> Hello again,
>>
>> I have started taking the MIT model through some longer runs and have
>> tried to restart them to safe time, but so far unsuccessfully.
>>
>> The runs produce two types of pickup files: pickup.ckptA.data and
>> pickup.chptB.data. I figured out that the 'A' file is a collection of
>> the data after the final time step and I am assuming the 'B' file is
>> from some time step before that.
>>
>> I have tried renaming pickup.ckptA.data to pickup.000004800 and set
>> nIter0 to 4800 to start the model at this point, but it aborts almost
>> immediately.
>>
>> What do I need to do to get it going successfully?!
>> Thanks,
>> Uli
> 
> Martin Losch // mailto:mlosch at awi-bremerhaven.de
> Alfred-Wegener-Institut für Polar- und Meeresforschung
> Postfach 120161, 27515 Bremerhaven, Germany
> Tel./Fax: ++49(471)4831-1872/1797
> http://www.awi-bremerhaven.de/People/show?mlosch
> 
> 
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://dev.mitgcm.org/mailman/listinfo/mitgcm-support
> 
> 


-- 
*********************************************************
Ulrike Riemenschneider,  Postdoctoral Investigator
Physical Oceanography Dept. MS #21
Woods Hole Oceanographic Institution
Woods Hole, MA 02543, USA

Phone: (+1) 508 289 2916 Fax: (+1) 508 457 2181
*********************************************************