Add MPAS Atmosphere NUOPC build by danrosen25 · Pull Request #1417 · MPAS-Dev/MPAS-Model

danrosen25 · 2026-03-10T17:32:40Z

Overview

The MPAS Atmosphere NUOPC cap infrastructure is designed to build an MPAS NUOPC library and Fortran module file for use within a NUOPC driven system. The initial work is an MPAS Atmosphere NUOPC cap "stub", which does not execute the MPAS Atmosphere. The stub provides entry point for initializing, running, and finalizing the future MPAS Atmosphere NUOPC model. Follow on work will include execution of the MPAS Atmosphere model from within the NUOPC cap along with adding coupling fields to the import and export states.

Testing infrastructure is implemented on a separate branch: https://github.com/NCAR/MPAS-Model-NUOPC-dev/tree/nuopc/testing

Configuration options

MPAS_PREFIX: Installation prefix used to determine location for lib and mod installation directories
MPAS_LIBDIR: Full path to the lib installation directory - location for installation MPAS NUOPC library
MPAS_MODDIR: Full path to the mod installation directory - location for installation of MPAS NUOPC Fortran module files
NUOPC: Generate NUOPC library for the desired CORE. Options are true | false (default)

Testing

Checkout the testing work from this branch
https://github.com/NCAR/MPAS-Model-NUOPC-dev/tree/nuopc/testing

Testing requires a system and environment capable of building and running MPAS-A with these additional requirements

cmake
an MPI implementation with mpirun included in users PATH
ESMF v8.5+ (which includes ESMX building infrastructure)
python

cd testing_and_setup/nuopc/atmosphere
./mpas_nuopc_atm_test.py

For detailed instructions see the README
https://github.com/NCAR/MPAS-Model-NUOPC-dev/tree/nuopc/testing/testing_and_setup/nuopc/atmosphere

danrosen25 · 2026-03-10T17:40:05Z

@mgduda @scrasmussen @uturuncoglu @anntsay

I've drafted a PR for the NUOPC cap infrastructure. I'd like for you to take a look before I mark this "ready" for review, in case you have any major revisions. I've rebased the work so that it builds on the MPAS_ESMF="external" work recently merged. I've also split the work into two commits, one for the NUOPC build infrastructure and stub cap, and a second one for the regression testing infrastructure. Please let me know if this work is on the right track.

The quicker we move forward the faster we can get to executing the running standalone (uncoupled) MPAS-Atmosphere cap, followed by coupled MPAS-Atmosphere caps. All follow on NUOPC work should include appropriate tests in testing_and_setup/nuopc/atmosphere/all_tests.ini

scrasmussen · 2026-03-27T18:59:21Z

This PR worked for me for Dan's testcase.

The mpas-hydro-develop branch I've been working on builds and I'm debugging things so it produces identical results at runtime with an MPAS idealized testcase. Once that is fixed, I'll rebase off this branch and use this testing framework to make sure it builds and runs. This looks good to me right now! And I'll be able to give better feedback once I've used it to add a testcase.

danrosen25 · 2026-05-13T18:09:47Z

@mgduda @scrasmussen @uturuncoglu
78c501e enhances the NUOPC build and test infrastructure and will better position this work for the MPAS Atmosphere standalone cap. It utilizes nccmp or cdo (two most popular netcdf comparison utilities) to compare netcdf files. The revision also fixes a few things like NCAR#14

* add installation locations for MPAS_PREFIX, MPAS_LIBDIR, MPAS_MODDIR * enabled NUOPC library with on, ON, 1, TRUE, true * disabled CORE_model build for NUOPC=true * disabled internal ESMF initialize and finalize for NUOPC=true * add nuopc folder to core_atmosphere with stub cap * add core, driver, framework, and external *.o to libmpas_nuopc.a

danrosen25 · 2026-06-15T19:55:18Z

@mgduda @scrasmussen @scrasmussen @anntsay
Hi team,
I'm simplifying this PR through moving the NUOPC cap infrastructure to a new branch, to reduce the number of line changes in this commit. Most of the line changes are in Makefiles and they throw an error if you try to build a NUOPC library for a CORE other than atmosphere. The NUOPC cap in this PR is just a stub, it does not call into the model but it tests the NUOPC build infrastructure.

The testing infrastructure can be cherry-picked from this branch
https://github.com/NCAR/MPAS-Model-NUOPC-dev/tree/nuopc/testing
da3baa9

We'll rebase our following iterations once this work is merged.

* update variables to MPAS_NUOPC_ prefix * create fullpath to MPAS_NUOPC_LIBDIR and MPAS_NUOPC_MODDIR * only create and delete installation if NUOPC=true * only clean nuopc files from MPAS_NUOPC_LIBDIR, MPAS_NUOPC_MODDIR

danrosen25 · 2026-07-16T02:26:29Z

@mgduda
See changes in 8b9b1e9
Note that I made a fix so that MPAS_NUOPC_LIBDIR and MPAS_NUOPC_MODDIR can only be deleted if they are empty and the clean command will only remove libmpas_nuopc.a and mpas_nuopc_*.mod. this is to prevent deleting non mpas_nuopc files and folders.

danrosen25 · 2026-07-16T12:41:20Z

 	( cd operators; $(MAKE) clean )
 	( cd driver; $(MAKE) clean )
+
+clean_nuopc:


@mgduda
What are your thoughts on cleaning the MPAS_NUOPC_LIBDIR and MPAS_NUOPC_MODDIR? I wanted the ability to install it in user defined directories but cleaning it from user defined directories can be unsafe. Say the MPAS_NUOPC_PREFIX is /usr, MPAS_NUOPC_LIBDIR is /lib, and MPAS_NUOPC_MODDIR is /include. Should I remove the clean functionality or do something different? Do we want to be able to delete the <MPAS_DIR>/lib and <MPAS_DIR>/mod directories when cleaning?

Installing files outside of the main MPAS-Model directory isn't something that we've had to think much about until now, so I'm still not sure what the best approach would be. Perhaps if we could determine that the installation mod and lib directories resided within the MPAS-Model directory, we could clean them, and otherwise, running make clean could print a message informing the user that they should manually remove the installation directories (which we could list in the message)?

mgduda · 2026-07-22T21:15:55Z

+	@echo "NUOPC build does not exist for the init_atmosphere core. Quitting."
+	@echo "************ ERROR ************"
+	@echo ""
+	exit 1


Rather than modifying the Makefile files under each core directory (besides core_atmosphere) to indicate that a NUOPC build is not supported, we could simplify matters by making a NUOPC build an "opt-in" feature. Here's an example of an alternative approach that would avoiding any modifications to cores that don't support NUOPC: mgduda@5c4563a .

mgduda · 2026-07-22T21:40:56Z

-all: mpas
+BUILD_ALL = mpas
+ifeq "$(NUOPC)" "true"
+BUILD_ALL = nuopc_lib


Should = be += here? Otherwise, compiling the atmosphere core with NUOPC=true will not produce an atmosphere_model executable.

@mgduda
We discussed this back in April 2026 NCAR#14. The guidance I was given was to utilize an existing preprocessor directive MPAS_NO_ESMF_INIT during NUOPC builds. This makes the atmosphere_model unusable because ESMF will never be initialized. For what it's worth I mentioned that I don't like using preprocessor directives for this type of behavior. In order to avoid this we'd need to add a flag that tracks whether ESMF was initialized by the MPAS code or by an external driver.

mgduda · 2026-07-22T21:49:38Z

+		core_$(CORE)/*.o \
+		core_$(CORE)/diagnostics/*.o \
+		core_$(CORE)/libchem/*.o \
+		core_$(CORE)/dynamics/*.o \


Some of these directories are specific to the atmosphere core and so I don't think they should be hard-wired in the src/Makefile for the nuopc_lib target. An alternative may be to let a core's build_options.mk file specify all core-specific files and directories that are needed to support its NUOPC build.

danrosen25 force-pushed the nuopc/build branch from 65ad017 to 33dedf6 Compare March 10, 2026 21:50

danrosen25 marked this pull request as ready for review March 30, 2026 23:32

danrosen25 force-pushed the nuopc/build branch from 2a32483 to 216a18f Compare June 15, 2026 19:50

danrosen25 requested a review from mgduda June 15, 2026 19:59

danrosen25 changed the title ~~Add MPAS Atmosphere NUOPC build and test infrastructure~~ Add MPAS Atmosphere NUOPC build Jun 30, 2026

danrosen25 assigned mgduda Jul 7, 2026

danrosen25 added the feature label Jul 7, 2026

mgduda requested changes Jul 14, 2026

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mgduda requested changes Jul 14, 2026

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Update MPAS NUOPC installation directories

8b9b1e9

* update variables to MPAS_NUOPC_ prefix * create fullpath to MPAS_NUOPC_LIBDIR and MPAS_NUOPC_MODDIR * only create and delete installation if NUOPC=true * only clean nuopc files from MPAS_NUOPC_LIBDIR, MPAS_NUOPC_MODDIR

danrosen25 force-pushed the nuopc/build branch from d4a008f to 8b9b1e9 Compare July 16, 2026 02:23

danrosen25 commented Jul 16, 2026

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mgduda self-requested a review July 22, 2026 21:14

mgduda requested changes Jul 22, 2026

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mgduda reviewed Jul 22, 2026

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Overview

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Testing

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danrosen25 commented Mar 10, 2026

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scrasmussen commented Mar 27, 2026

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danrosen25 commented May 13, 2026

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danrosen25 commented Mar 10, 2026 •

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