[mpas-developers] Provenance in output files

[Michael Duda]

Hi, Doug.

I'm testing out the branch now, and I have a few initial comments.

I noticed that the variables to hold the version, model name, and core
name have been added to the mpas_constants.F module. This module is
currently used for physical constants, so I'd suggest we move these
attribute variables elsewhere. Currently, we keep the attributes
on_a_sphere and sphere_radius in the mesh type; but perhaps a better
place for modelName, coreName, version, and history would be inside the
domain type. If at some point in the future we add the ability to
instantiate multiple models in the same MPAS executable, I think it
would make sense to have attributes like modelName in the individual
instances of the domain_type, which is supposed to encapsulate the
complete computational state of the model.

Regarding the naming of these attributes, perhaps we could rename
'version' to 'model_version' to be less ambiguous. Also, given that the
run command in the history attribute already includes the name of the
specific executable, is there real value in including the attribute
'core_name'?

As you pointed out, dealing with the history string can get messy.
Declaring local variables as StrKIND*2 and StrKIND*4 should work in most
instances, but we might want to give a little more thought to whether
this couldn't be handled in a more robust way. For example in cycling
experiments or for longer runs that periodically restart, the history
attribute could easily overflow with repetitions of "mpirun -n 128
nhyd_atmos_model.exe". Fortran 2003 does support allocatable character
strings, and recent versions of ifort and pgf90 have implemented support
for this, but correct support in gfortran appears to require version
4.8.0; and, I've not yet checked the BG/Q and xlf compilers. This also
raises the question of whether running the model constitutes
"modifications to the original data" (as the CF conventions describe the
"history attribute").

Thanks for all of your work on this so far, and I'll let you know how it
goes with my testing.

Cheers,
Michael


On Tue, Apr 02, 2013 at 02:49:48PM -0600, Doug Jacobsen wrote:
> Hi Everyone,
> 
> I spent part of this morning trying to add some provenance information to
> the output files that MPAS creates. Currently I have it adding model name,
> core name, and a version string to each output file, and adding the command
> that was used to run the model to the history attribute.
> 
> You can preview the changes in the following branch.
> branches/history_attribute
> 
> The current way to define this information is to modify Registry.xml with
> the following syntax.
> <registry model="mpas" core="core_name" version="version_string">
> ...
> </registry>
> 
> Then when the model is built, there are parameters created in
> src/framework/mpas_constants.F named
> modelName
> coreName
> version
> history
> 
> History is read in from the input grid upon runtime, and written to all
> output files with the additional information describing how MPAS was run.
> Currently it's hard coded to be "mpirun -n ${PROCS} ${CORE}_model.exe"
> since we require MPI at build time.
> 
> If the model, core, and version strings are missing from Registry.xml
> currently it replaces their values with "MISSING", and writes those to the
> output files so there is no negative consequences.
> 
> I've tested this branch with the ocean model and it doesn't change results
> in the current trunk. I also tested building with the shallow water core,
> when the Registry.xml information is missing.
> 
> I would like to merge this branch back onto the trunk within the next few
> days unless anyone has any objections, as I think this additional
> information will be important to have in the future.
> 
> Any comments/questions are welcome.
> 
> Thanks
> Doug

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