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

[Jean-Michel Campin]

Hi Martin,

Just one comment regarding forward grad of exp. global_ocean.cs32x15.seaice_dynmix :
Even before you made changes with recip_deltaT in seaice_lsr.F,
other than gfortran compilers were not giving very accurate fwd grad:
1) pgf77, mpi, -ieee:
 tr_acesgrid-adm_20160120_0/summary.txt:    Y Y Y Y  8>10< 2 pass  global_ocean.cs32x15.seaice_dynmix
2) pgf77, mpi, -fast:
 tr_acesgrid-adm_20160119_0/summary.txt:    Y Y Y Y  9> 3< 2 FAIL  global_ocean.cs32x15.seaice_dynmix
3) open64, no mpi, -devel:
 tr_acesgrid-tuv_20160119_0/summary.txt:    Y Y Y Y  8>11< 2 pass  global_ocean.cs32x15.seaice_dynmix
4) open64, mpi, -devel:
 tr_engaging-o64Adm_20160120_0/summary.txt: Y Y Y Y  8>11< 2 pass  global_ocean.cs32x15.seaice_dynmix
5) open64, mpi, -fast:
 tr_engaging-o64Adm_20160119_0/summary.txt: Y Y Y Y  8>11< 2 pass  global_ocean.cs32x15.seaice_dynmix

It's not impossible that, in some cases, using recip_deltaT will reduce differences between compilers.

Cheers,
Jean-Michel

On Thu, Jan 21, 2016 at 07:27:25AM +0100, Martin Losch wrote:
> OK,
> 
> I am waiting for the tests to complete in the afternoon an then do the update of adjoint and tlm results
> 
> Martin
> 
> > On 20 Jan 2016, at 18:12, Jean-Michel Campin <jmc at ocean.mit.edu> wrote:
> > 
> > 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
> >>> 
> >>> 
> >>> _______________________________________________
> >>> MITgcm-cvs mailing list
> >>> MITgcm-cvs at mitgcm.org
> >>> http://mitgcm.org/mailman/listinfo/mitgcm-cvs
> >> 
> >> 
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