= Name and subject of the action

Last edition: '''[[Wikinfo(changed_ts)]]''' by '''[[Wikinfo(changed_by)]]'''

The PI is responsible to closely follow the progress of the action, 
and especially to contact NEMO project manager if 
the delay on preview (or review) are longer than the 2 weeks expected.

[[PageOutline(2, , inline)]]

== Summary

||=Action       || OASIS_TESTCASE : create a test case for coupling with OASIS                       ||
||=PI(S)        || Claire Lévy                                                 ||
||=Digest       || Motivations and main tasks: create a simple testcase using OASIS to help building new coupled configurations     ||
||=Dependencies || OASIS                                                ||
||=Branch       || source:NEMO/branches/2020/dev_r12565_VALID-11_clevy_OASIS_TESTCASE ||
||=Previewer(s) || E. Maisonnave & Laure Coquart                         ||
||=Reviewer(s)  || E. Maisonnave & Laure Coquart                         ||
||=Ticket       || #2379                                                 ||

=== Description


Create a simple testcase using OASIS to help building new coupled configurations.[[br]]
Will use OASIS and a simplified fake atmosphere (TOY_ATM in OASIS wording.[[br]]
May do more than only ocean-atmosphere coupling (to be discussed).[[br]]
Useful as coupling demonstrator and for first level valisation of coupling with OASIS in future NEMO versions.



=== Implementation


As for the test case defined in STEP1 (see below):
* no changes in NEMO code
* Changes in &namsbc_cpl namelist
* Need to add the TOY_ATM software, as a simplified /fake atmosphere somewhere to be able tu run this test case


=== Documentation updates


Updates needed:
* On line documentation (to be committed in rst files) : 
  * https://forge.ipsl.jussieu.fr/nemo/chrome/site/doc/NEMO/guide/html/test_cases.html
  * https://forge.ipsl.jussieu.fr/nemo/chrome/site/doc/NEMO/guide/html/coupling.html
* Reference manual: does not seem to include information the key_oa3mct_v3 cpp key, needed for this test case. Is it useful?


== Preview 


Methodology
==== STEP 1: Implement in the up-to-date version for 2020 the test case developed in 2018
Restarting from /ccc/work/cont003/gen7451/clevy/VALID_CPL_4.0/trunk/cfgs/CPL_TOYATM in irene computer, implement the CPL_OASIS in the up-to-date NEMO version, as a test case (in "dev_branch"/tests).

CPL_OASIS test case description:
* Based on the ORCA2_ICE_PISCES reference configuration, activate coupling to a TOYATM (kindly offered by Eric M.) through OASIS
* coupled fields (from &namsbc_cpl namelist in namelist_cfg file)
* runing 10days, coupling every time step (nn_fsbc=1)


* The test cases needs OASIS and a simple TOYATM
* Where should the TOYATM be installed? In the test case, in NEMO tools? elsewhere?
* Validation of the test case remains to be defined more precisely (check OASIS output ATSSTSST_toyatm_01.nc compared to ocean SST ?)

==== STEP 2: is this the final version of the expected test case?
* Adding other couplings?
* Checking sea-ice?

==== STEP 3: implement final test case
Implement the finalised test case as part of the usual validation testbed, and also in the github for NEMO test cases

Answer from reviewers is in the ticket #2379.
For E. Maisonnave & L. Coquart, review is successful and development can start

==== Validation:
This toy is able to validate a simplified OASIS based coupled configuration of NEMO in such a way that:
* the OASIS library can be compiled on the targeted machine (OASIS libraries available in the OASIS directory)
* the OASIS library can be linked with a coupled configuration of NEMO (the NEMO executable is available in the NEMO cfg directory) and an atmosphere toy model (executable available in the tools/TOYATM directory)
* an MPI MPMD system (two executables at the same time) can be launched on the machine and a successful simulation can be achieved if :

* a run.stat file is produced and includes 160 iterations: 
nemo_iterations=`wc -l run.stat | awk {'print $1'} | grep 160`; [ -n "$nemo_iteration" ] && echo true || echo false

* OASIS indicates a successful end of the run:
success=`grep "SUCCESSFUL RUN" debug.root.0? | wc -l | grep 2`; [ -n "$success" ] && echo true || echo false

* the sea surface temperature (Tropical Pacific region) as seen by the toy atmosphere model is close to 300.20 K and the difference between the end and the beginning values doesn't exceed 0.5 K
This can be checked e.g. in the check file produced by the commands: ncks -h -v ATSSTSST -d nx,80,120 -d ny,0,10 ATSSTSST_toyatm_01.nc tropical_sst.nc ; ncwa -h -a nx,ny tropical_sst.nc check.nc

== Development
* The CPL_OASIS test case is now avalaible in the development branch (see changeset https://forge.ipsl.jussieu.fr/nemo/changeset/12663).
* The updated TOYATM tool is now available in an additional tools branch, see changeset https://forge.ipsl.jussieu.fr/nemo/changeset/12669

IMPORTANT: for now, I've not been able to commit in the development branch the change for external tools (in order to point on the new branch https://forge.ipsl.jussieu.fr/nemo/browser/utils/tools_CPL_OASIS_ticket2379_2020/.  TEMPORARY BYPASS:
* Download the development branch
{{{
svn co http://forge.ipsl.jussieu.fr/nemo/svn/NEMO/branches/2020/dev_r12565_VALID-11_clevy_OASIS_TESTCASE
}}}

The tools subdirectory is now extracted for this branch from the new development branch created to update TOYATM: tools_CPL_OASIS_ticket2379_2020 [[br]]

'''More details on how to set up and run the CPL_OASIS test case in ./tests/CPL_OASIS/README.md'''
== Tests

{{{#!box width=50em info
[[Include(wiki:Developers/DevProcess#tests)]]
}}}

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== Review

{{{#!box width=50em info
[[Include(wiki:Developers/DevProcess#review)]]
}}}

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