Improve oasis grid writing

[ukmo-juan-castillo]

Pull Request Summary

Rewrite the cpl_oasis_grid subroutine for better performance and to use OASIS and SCRIP standards.

Description

This is just a change providing a small performance gain in the code (mainly substituting three identical double loops by a single one), using the SCRIP convention to write grid corners, and the oasis convention to declare the grid mask. It should not change answers, but the grid.nc file generated by OASIS will change due to a rearrangement of data in regular grids and the change of mask values for SMC grids.

The reviewer is encouraged to look at the OASIS and SCRIP documentation.
Possible label that could be applied could be enhancement.

Issue(s) addressed

• fixes Improvement of oasis grid write routine #1353

Commit Message

Rewrite the cpl_oasis_grid subroutine for better performance and to use OASIS and SCRIP standards.

Check list

• Branch is up to date with the authoritative repository (NOAA-EMC) develop branch.
• Checked the checklist for a developer submitting to develop.
• If a version number update is required, checked the updating version number checklist.
• If a new feature was added, a regression test for testing the new feature is added.

Testing

• How were these changes tested?
  Regression tests
• Are the changes covered by regression tests? (If not, why? Do new tests need to be added?)
  Yes, they are covered by the tp2.14 tests
• Have the matrix regression tests been run (if yes, please note HPC and compiler)?
  Yes
• Please indicate the expected changes in the regression test output, (Note the list of known non-identical tests.)
  The change only affect tests tp2.14. The only change in results has to do with the changes in the grid.nc OASIS output file discussed above.
• Please provide the summary output of matrix.comp (matrix.Diff.txt, matrixCompFull.txt and matrixCompSummary.txt):

[JessicaMeixner-NOAA]

Thanks for the PR @ukmo-juan-castillo - Ill start the regression tests from the NCEP side. Since this code is mostly with the OASIS coupling, I'm also going to ask @mickaelaccensi to review as he's more of an expert than I am.

[JessicaMeixner-NOAA]

@ukmo-juan-castillo Do you have any regression tests information about what might be expected to be changed answer wise? I know that @ukmo-ccbunney used to run those, so I don't know if you or others were running those as well?

[ukmo-juan-castillo]

Regression test information:

matrixCompSummary.txt-ww3_tp2.14.txt

[ukmo-juan-castillo]

@ukmo-juan-castillo Do you have any regression tests information about what might be expected to be changed answer wise? I know that @ukmo-ccbunney used to run those, so I don't know if you or others were running those as well?

Thank you, it is some time since I opened a PR but @ukmo-ccbunney helped me to refresh the procedure. I run the regtests myself, my old scripts were still working and it was straightforward. I was also thinking of @mickaelaccensi as a reviewer.

[mickaelaccensi]

I approve to write the mask as in scrip convention since it is already how it is created when reading MASPTA. ok for the order of the cell corners

[JessicaMeixner-NOAA]

@ukmo-juan-castillo - Okay to make sure we do proper testing on our end - we're trying to resovle a bug #1350

That being said, everything I have tested and looked at so far is okay - and given @mickaelaccensi review this should be merged in a couple of days. If that delay is an issue, let me know and I'll see what we can do.

[ukmo-juan-castillo]

@ukmo-juan-castillo - Okay to make sure we do proper testing on our end - we're trying to resovle a bug #1350

That being said, everything I have tested and looked at so far is okay - and given @mickaelaccensi review this should be merged in a couple of days. If that delay is an issue, let me know and I'll see what we can do.

Thank you Jessica. There is no urgency in having this merged, in fact it is something I wanted to do for a long time but never had the time. I will be creating more issues in the near future with similar code changes.