dev/emc branch does not build without CCPP as a pre-requisite.

[aerorahul]

Describe the bug
The removal (or replacement) of IPD with CCPP introduced an explicit dependency on CCPP of the dynamical core in the dev/emc branch. #ifdef CCPP was removed.
As a result, the dycore now needs to be provided a path to the compiled fortran modules from CCPP.
This change no longer allows the DA development in JEDI to use dev/emc branch for dry dynamical core testing.

The #ifdef protections to CCPP need to be reinstated to allow the use of the dynamical core without CCPP.

Expected behavior
Allow the dynamical core to be built without CCPP.

Tagging @climbfuji

[climbfuji]

Another option is to allow building a stub CCPP that has no physics, just the lightweight framework with an empty stub suite/scheme. I played with this when @aerorahul reported the issue to me first, and it worked just fine. This would also align better with the idea of having an abstract interface to the fast physics with different backends (GFDL physics, CCPP physics, no/stub physics) that the GFDL developers and I have been talking about in the recent months.

[lharris4]

This will need to be a priority. Many FV3-based models (especially GEOS, F-GOALS, and much of the GFDL modeling hierarchy, including simplified models in use for GFD research) do not use CCPP and there should be no reason a dynamical core needs to be tied to any particular physics framework. Dom has already made very good progress on this end. Thanks, Lucas

…

On Fri, Sep 10, 2021 at 4:51 PM Dom Heinzeller ***@***.***> wrote: Another option is to allow building a stub CCPP that has no physics, just the lightweight framework with an empty stub suite/scheme. I played with this when @aerorahul <https://github.com/aerorahul> reported the issue to me first, and it worked just fine. This would also align better with the idea of having an abstract interface to the fast physics with different backends (GFDL physics, CCPP physics, no/stub physics) that the GFDL developers and I have been talking about in the recent months. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#142 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AMUQRVHBMX67NYJE6Z5TJ4LUBJVURANCNFSM5D2CT22A> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[climbfuji]

I created a PR to compile dev/emc without CCPP dependencies, only FMS and netCDF (because FMS needs it) are required:#231

That PR triggered a discussion, and @lharris4 suggested to use the new "intermediate physics" layer, available in the main branch, to accomplish the same. See #231 (comment) and following comments.

[bensonr]

@climbfuji - With all of the current work in issue #231 and here, I believe this can be closed. If not, feel free to reopen

[climbfuji]

Ok with me, thanks!