[MITgcm-support] Re: Restart after changing deltatT

[samar khatiwala]

Hi Jean-Michel

Your fix to diff_base_multiple.F seems to have worked (but see below). The
dumps are now being written at the expected frequency (including the
initial iteration). So I have dumps at:
0003600000 t=0
0003729600 t=5 year
0003859200 t=10 year
(and hopefully one final one at year 15)

However, the pickup is still not right. I have pChkptFreq= 466560000.
(corresponding to 15 years), but instead I get a pickup at
iter = 0003859200 which is year 10.

Since my run is only 15 years long (max I can do with the wall clock limit
on our cluster), I will probably not get the final pickup I wanted.

Help!!

Thanks, Samar

On Wed, 4 May 2005, Jean-Michel Campin wrote:

> Hi Samar,
>
> Thanks for the report.
> I fixed "diff_base_multiple.F" and it should be much better now.
> But I don't have a good explanation for not having
> a dump at the beginning.
> Are you using
> #define MINIMAL_TAVE_OUTPUT
> in CPP_OPTIONS.h ?
>
> Jean-Michel
>
> On Wed, May 04, 2005 at 01:04:04PM -0400, samar khatiwala wrote:
> > Hi Jean-Michel
> >
> > I tried setting baseTime as you suggested (it was more attractive than
> > the other option of setting both nIter0 and startTime). I get
> > unpredictable (at least by me!) results and was wondering if you could
> > help me diagnose the problem.
> >
> > Details:
> > I have a pickup file at iter=3600000 from a run with deltaTClock=43200.
> > I now switch to deltaTClock=1200. New data file looks like:
> >
> >  nIter0  =3600000,
> >  baseTime =151200000000.0,
> >  nTimeSteps = 388800,
> >  deltaTClock = 1200.0,
> > ...
> >  pChkptFreq= 466560000.,
> >  dumpFreq=   155520000.,
> >
> > The baseTime I calculated using your formula:
> >   baseTime = 3600000*(43200 - 1200) = 151200000000.
> >
> > I expect to see dumps every 5 years, and a pickup at year 15. Instead, I
> > get dumps at iter:
> > 0003628800 -> (3628800-3600000)*1200/86400/360 = 1.111 year
> > 0003758400 -> (3758400-3600000)*1200/86400/360 = 6.111 year
> > 0003888000 -> (3888000-3600000)*1200/86400/360 = 11.111 year
> >
> > and a pickup at iter:
> > 0003888000 -> (3888000-3600000)*1200/86400/360 = 11.111 year
> >
> > Note that there is no dump at the initial iteration, 0003600000.
> >
> > What am I doing wrong here?
> >
> > Thanks, Samar
> >
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