[MITgcm-devel] Identical executable producing diverging results

[Nguyen, An T (3248-Affiliate)]

hi Patrick,

The 2 STDOUT files I sent via attachment starts at the same niter0 = 0.  The STDOUT.0000 in /nobackup2a/menemenl/arctic/arctic_9km/MITGCM/exe_firstrun_1992_2009/ is from a pick-up time and is not what I'm using for comparison here.  I used stdout.216096 in that directory to compare with my current run (i.e., head -4000 stdout.216096 > STDOUT.0000_Jun09a).

An
________________________________________
From: Patrick Heimbach [heimbach at MIT.EDU]
Sent: Friday, December 25, 2009 2:22 AM
To: MITgcm-devel at mitgcm.org
Subject: Re: [MITgcm-devel] Identical executable producing diverging results

Hi An,

I diff-ed the two STDOUT.0000
and it appears that one setup starts from
   niter0=0,
the other one from
   niter0=601824,

That probably explains your problem.

-Patrick



On Dec 23, 2009, at 9:35 PM, An T Nguyen wrote:

> Hi all,
>
> I wasn't sure where I should send this email, but I'm hoping
> someone could help me with this issue:
>
> I ran 2 experiments (one @ 18km and one @ 9km resolution) back in
> June 2009, and now am repeating
> the exact experiments.  The results are diverging, and in 1 case
> the model crashes in 2002 while the
> original experiment ran to 2009 without any problem.  The
> divergence is true for both 18km and 9km
> runs, and the first place it diverges is at exf_hflux_max/min/mean/
> sd/del2 and
> exf_sflux_max/min/mean/sd/del2 at time-step 0 in the STDOUT file.
>
> I include here the beginning of two 9-km STDOUT files, one of the
> original run back in June, and one
> of this month run.  All input files are identical.  Forcing files
> and executables (mitgcmuv) are also identical.  The locations of
> these 2 runs are:
>
> Original:
> cfe2:/nobackup2a/menemenl/arctic/arctic_9km/MITgcm/
> exe_firstrun_1992_2009/
>
> Repeat:
> cfe2:/nobackup1/atnguyen/arctic/MITgcm/exe_firstrun_1992_2009
>
> The 18km runs also differ at the same place.  Could this be due to
> some changes on the Columbia side?
>
> I also notice that if I repeat the same experiments from pick-up
> files that were generated after Jun 27, 2009, then I get exact
> results.  So it seems that results generated prior to approximately
> this date can not be repeated.
>
> Thanks,
> An
>

---
Patrick Heimbach | heimbach at mit.edu | http://www.mit.edu/~heimbach
MIT | EAPS 54-1518 | 77 Massachusetts Ave | Cambridge MA 02139 USA
FON +1-617-253-5259 | FAX +1-617-253-4464 | SKYPE patrick.heimbach



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