[MITgcm-devel] Fwd: [MITgcm-cvs] MITgcm/pkg/seaice CVS Commit

[Jean-Michel Campin]

Hi Martin,

I would suggest to go for 2 or 3, so that we get updated output for 
all the experiments we understand why the results did change.
Regarding global_ocean.cs32x15.seaice_dynmix, it's up to you:
you could keep the old (and good) reference output or update it with
a new and less good output.

Cheers,
Jean-Michel

On Wed, Jan 20, 2016 at 05:00:35PM +0100, Martin Losch wrote:
> Hi,
> 
> this recent change in seaice_lsr.F (replace 1/SEAICE_deltaTdyn wiht precomputed recip_deltaT) changes some results at truncation level, also for adjoint and tlm. For the adm and tlm seaice_dynmix experiment, however, the FD gradients are, totally unexpectly, broken (only 2 digits remain and the comparision to the adjoint and tlm gradients are 2 orders of magnitude less accurate). Since the adjoint and tangent-linear gradients only change a little (11 digits of agreement remain, so that I get a ???pass"), and the cost function is also not affected as much, I am a little at loss, what may cause this.
> 
> What should I do?
> 1. revert to old code: go back to 1/SEAICE_deltaTdyn instead of recip_deltaT
> 2. update all but the seaice_dynmix experiment
> 3. update all experiments and worry about the accuracy later?
> 
> Martin
> 
> > Begin forwarded message:
> > 
> > From: Martin Losch <mlosch at forge.csail.mit.edu>
> > Subject: [MITgcm-cvs] MITgcm/pkg/seaice CVS Commit
> > Date: 20 Jan 2016 15:02:53 CET
> > To: <mitgcm-cvs at mitgcm.org>
> > Reply-To: <MITgcm-cvs at mitgcm.org>
> > 
> > Update of /u/gcmpack/MITgcm/pkg/seaice
> > In directory forge:/tmp/cvs-serv1185/pkg/seaice
> > 
> > Modified Files:
> > 	seaice_lsr.F 
> > Log Message:
> > replace 1./SEAICE_deltaTdyn with recip_deltaT for better vectorisation
> > affects some experiments at truncation level
> > 
> > 
> > _______________________________________________
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> > MITgcm-cvs at mitgcm.org
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> 
> 
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