Update for CICE5 with CMake by anton-seaice · Pull Request #1138 · ACCESS-NRI/ACCESS-Hive-Docs

anton-seaice · 2026-02-02T23:59:15Z

This makes the CICE5 instructions simpler for changing processor count, based on the newer CMake build

github-actions · 2026-02-02T23:59:49Z

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docs/models/build_a_model/build_source_code.md

anton-seaice · 2026-02-18T22:46:31Z

Ready to go @ACCESS-NRI/hivedocsteam and @manodeep

atteggiani

Can you please reintroduce all the deleted assets? :D

anton-seaice · 2026-02-18T23:34:31Z

OOPPS!

anton-seaice · 2026-02-18T23:36:21Z

Try again @atteggiani

manodeep · 2026-02-18T23:40:01Z

Hahahaha - I was wondering about the deleted assets! Didn't look relevant to the context :D

manodeep

Thanks for updating the docs - I have requested some clarifications, which should make the document easier to parse for users

docs/models/build_a_model/build_source_code.md

manodeep · 2026-02-18T23:43:45Z

docs/models/build_a_model/build_source_code.md

 * __MOM5__: In `ocean/input.nml`, change `layout` in the `&ocean_model_nml` namelist, which describes the number of chunks in the x and y directions in `nx,ny` format. In `config.yaml`, change the `ocean: ncpus` to the product of `nx` and `ny`.
 * __CICE4__: Requires the user to have their own Spack installation. In the user's Spack installation, in `${SPACK_ROOT}/spack-packages/packages/cice4/package.py`, modify the entries in the `__targets` dictionary to the desired number of processes and blocks (the product of the blocks must be the same as the processes). The resulting executable name is `cice_<driver>_<grid>_<blocks>_<nprocs>p.exe`, which must be specified in the `config.yaml`. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the `ice: ncpus` to the desired number of processes.
-* __CICE5__: Requires the user to have their own Spack installation. In the user's Spack installation, in `${SPACK_ROOT}/spack-packages/packages/cice5/package.py`, modify the entries in the `self.__targets` dictionary and `self.add_target` calls to the desired number of processes and blocks (the product of the blocks must be the same as the processes). The resulting executable name is `cice_<driver>_<grid>_<blocks>_<nprocs>p.exe`, which must be specified in the `config.yaml`. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the `ice: ncpus` to the desired number of processes.
+* __CICE5__: In spack.yaml, modify or add the [five variants _nxglob_, _nyglob_, _blckx_, _blcky_, _mxblcks_](https://github.com/search?q=repo%3AACCESS-NRI%2Faccess-spack-packages+%5C%22nxglob%5C%22+%5C%22nyglob%5C%22+%5C%22blckx%5C%22+%5C%22blcky%5C%22+%5C%22mxblcks%5C%22&type=code) to the desired number of processes and blocks (see Section 4.7 of the CICE5 [documentation](https://github.com/ACCESS-NRI/cice5/blob/master/doc/cicedoc.pdf)). For one degree resolution models, this can be easily achieved by scaling _blckx_ inversely with the number of processes—for example, if the process count is halved, double _blckx_. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the executable name to the new build and change `ice: ncpus` to the desired number of processes.


Might be good to add a clarification that the user needs to rebuild CICE5 to run on a different number of cores. Also, might be good to add a link to the relevant spack.yaml here

I have many thoughts :)

may be remove "easily" from the "... easily achieved ..."

does cice_ncpus need to be a factor of nxglob?

does the product of cice_ncpus and _blckx_ need to i) equal or ii) exceed nxglob?

does the user need to specify all 5 variants or could they get away with specifying the ones they are changing

I thought mxblcks was required to be exactly 1 (from that #error line in the code that you showed me) - is that no longer the case?

I never know how much detail to write in access-hive-docs ... its not something easy to explain in 4 sentences!

"easily" is maybe optimistic

Some of these things are true for esm1.6 and not true for om2 -

We found for esm1.6 that mxblcks needs to be 1, and blckx needs to be an exact factor of nxglob. But these are not true to om2.

They do need to set all 5 variants (this makes more sense in the om2 context where there are multiple grid sizes, and less sense in the esm1.6 context)

Does ensuring nxglob/blckx = nprocs for esm1.6 always work ?

atteggiani

Thank you @anton-seaice, it looks good.

I just added some comments to make the whole paragraph (also the portion not touched by this PR) more legible.

atteggiani · 2026-02-18T23:52:02Z

docs/models/build_a_model/build_source_code.md

 * __UM7__: In `atmosphere/um_env.yaml`, change `UM_ATM_NPROCX` and `UM_ATM_NPROCY`, which describe the number of chunks in the x and y directions, as well as `UM_NPES` to the product of `UM_ATM_NPROCX` and `UM_ATM_NPROCY`. In `config.yaml`, change the `atmosphere: ncpus` to be the same as `UM_NPES`.
 * __MOM5__: In `ocean/input.nml`, change `layout` in the `&ocean_model_nml` namelist, which describes the number of chunks in the x and y directions in `nx,ny` format. In `config.yaml`, change the `ocean: ncpus` to the product of `nx` and `ny`.
 * __CICE4__: Requires the user to have their own Spack installation. In the user's Spack installation, in `${SPACK_ROOT}/spack-packages/packages/cice4/package.py`, modify the entries in the `__targets` dictionary to the desired number of processes and blocks (the product of the blocks must be the same as the processes). The resulting executable name is `cice_<driver>_<grid>_<blocks>_<nprocs>p.exe`, which must be specified in the `config.yaml`. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the `ice: ncpus` to the desired number of processes.


Suggested change

* __UM7__: In `atmosphere/um_env.yaml`, change `UM_ATM_NPROCX` and `UM_ATM_NPROCY`, which describe the number of chunks in the x and y directions, as well as `UM_NPES` to the product of `UM_ATM_NPROCX` and `UM_ATM_NPROCY`. In `config.yaml`, change the `atmosphere: ncpus` to be the same as `UM_NPES`.

* __MOM5__: In `ocean/input.nml`, change `layout` in the `&ocean_model_nml` namelist, which describes the number of chunks in the x and y directions in `nx,ny` format. In `config.yaml`, change the `ocean: ncpus` to the product of `nx` and `ny`.

* __CICE4__: Requires the user to have their own Spack installation. In the user's Spack installation, in `${SPACK_ROOT}/spack-packages/packages/cice4/package.py`, modify the entries in the `__targets` dictionary to the desired number of processes and blocks (the product of the blocks must be the same as the processes). The resulting executable name is `cice_<driver>_<grid>_<blocks>_<nprocs>p.exe`, which must be specified in the `config.yaml`. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the `ice: ncpus` to the desired number of processes.

- **UM7**

- In `atmosphere/um_env.yaml`, change `UM_ATM_NPROCX` and `UM_ATM_NPROCY`, which describe the number of chunks in the x and y directions, as well as `UM_NPES` to the product of `UM_ATM_NPROCX` and `UM_ATM_NPROCY`.

- In `config.yaml`, change the `atmosphere: ncpus` to be the same as `UM_NPES`.

- **MOM5**

- In `ocean/input.nml`, change `layout` in the `&ocean_model_nml` namelist, which describes the number of chunks in the x and y directions in `nx,ny` format.

- In `config.yaml`, change the `ocean: ncpus` to the product of `nx` and `ny`.

- **CICE4**<br>

Requires the user to have their [own _Spack_ installation](/getting_started/spack/).

- In the user's Spack installation, in `${SPACK_ROOT}/spack-packages/packages/cice4/package.py`, modify the entries in the `__targets` dictionary to the desired number of processes and blocks (the product of the blocks must be the same as the processes). The resulting executable name is `cice_<driver>_<grid>_<blocks>_<nprocs>p.exe`, which must be specified in the `config.yaml`.

- In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the `ice: ncpus` to the desired number of processes.

atteggiani · 2026-02-18T23:56:12Z

docs/models/build_a_model/build_source_code.md

 * __MOM5__: In `ocean/input.nml`, change `layout` in the `&ocean_model_nml` namelist, which describes the number of chunks in the x and y directions in `nx,ny` format. In `config.yaml`, change the `ocean: ncpus` to the product of `nx` and `ny`.
 * __CICE4__: Requires the user to have their own Spack installation. In the user's Spack installation, in `${SPACK_ROOT}/spack-packages/packages/cice4/package.py`, modify the entries in the `__targets` dictionary to the desired number of processes and blocks (the product of the blocks must be the same as the processes). The resulting executable name is `cice_<driver>_<grid>_<blocks>_<nprocs>p.exe`, which must be specified in the `config.yaml`. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the `ice: ncpus` to the desired number of processes.
-* __CICE5__: Requires the user to have their own Spack installation. In the user's Spack installation, in `${SPACK_ROOT}/spack-packages/packages/cice5/package.py`, modify the entries in the `self.__targets` dictionary and `self.add_target` calls to the desired number of processes and blocks (the product of the blocks must be the same as the processes). The resulting executable name is `cice_<driver>_<grid>_<blocks>_<nprocs>p.exe`, which must be specified in the `config.yaml`. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the `ice: ncpus` to the desired number of processes.
+* __CICE5__: In spack.yaml, modify or add the [five variants _nxglob_, _nyglob_, _blckx_, _blcky_, _mxblcks_](https://github.com/search?q=repo%3AACCESS-NRI%2Faccess-spack-packages+%5C%22nxglob%5C%22+%5C%22nyglob%5C%22+%5C%22blckx%5C%22+%5C%22blcky%5C%22+%5C%22mxblcks%5C%22&type=code) to the desired number of processes and blocks (see Section 4.7 of the CICE5 [documentation](https://github.com/ACCESS-NRI/cice5/blob/master/doc/cicedoc.pdf)). For one degree resolution models, this can be easily achieved by scaling _blckx_ inversely with the number of processes—for example, if the process count is halved, double _blckx_. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the executable name to the new build and change `ice: ncpus` to the desired number of processes.


Suggested change

* __CICE5__: In spack.yaml, modify or add the [five variants _nxglob_, _nyglob_, _blckx_, _blcky_, _mxblcks_](https://github.com/search?q=repo%3AACCESS-NRI%2Faccess-spack-packages+%5C%22nxglob%5C%22+%5C%22nyglob%5C%22+%5C%22blckx%5C%22+%5C%22blcky%5C%22+%5C%22mxblcks%5C%22&type=code) to the desired number of processes and blocks (see Section 4.7 of the CICE5 [documentation](https://github.com/ACCESS-NRI/cice5/blob/master/doc/cicedoc.pdf)). For one degree resolution models, this can be easily achieved by scaling _blckx_ inversely with the number of processes—for example, if the process count is halved, double _blckx_. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the executable name to the new build and change `ice: ncpus` to the desired number of processes.

- **CICE5**

- In `spack.yaml`, modify or add the [five variants `nxglob`, `nyglob`, `blckx`, `blcky`, `mxblcks`](https://github.com/search?q=repo%3AACCESS-NRI%2Faccess-spack-packages+%5C%22nxglob%5C%22+%5C%22nyglob%5C%22+%5C%22blckx%5C%22+%5C%22blcky%5C%22+%5C%22mxblcks%5C%22&type=code) to the desired number of processes and blocks (for details, see Section 4.7 of [CICE5 documentation](https://github.com/ACCESS-NRI/cice5/blob/master/doc/cicedoc.pdf)). For one degree resolution models, this can be easily achieved by scaling `blckx` inversely with the number of processes (for example, if the process count is halved, double the value of `blckx`).

- In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes.

- In the `config.yaml`, change the executable name to the new build and change `ice: ncpus` to the desired number of processes.

anton-seaice · 2026-02-19T23:55:50Z

Is this clearer @manodeep ?

anton-seaice self-assigned this Feb 2, 2026

anton-seaice commented Feb 10, 2026

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anton-seaice marked this pull request as ready for review February 18, 2026 22:45

anton-seaice requested a review from a team as a code owner February 18, 2026 22:45

anton-seaice requested a review from manodeep February 18, 2026 22:46

atteggiani requested changes Feb 18, 2026

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Update with CICE5 for CMake

7735974

anton-seaice force-pushed the 1137 branch from 511b8b5 to 7735974 Compare February 18, 2026 23:35

manodeep requested changes Feb 18, 2026

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atteggiani requested changes Feb 18, 2026

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anton-seaice added 2 commits February 20, 2026 10:37

Merge remote-tracking branch 'origin/development' into 1137

2991050

review comments

9ffddde

-* __CICE5__: In spack.yaml, modify or add the [five variants _nxglob_, _nyglob_, _blckx_, _blcky_, _mxblcks_](https://github.com/search?q=repo%3AACCESS-NRI%2Faccess-spack-packages+%5C%22nxglob%5C%22+%5C%22nyglob%5C%22+%5C%22blckx%5C%22+%5C%22blcky%5C%22+%5C%22mxblcks%5C%22&type=code) to the desired number of processes and blocks (see Section 4.7 of the CICE5 [documentation](https://github.com/ACCESS-NRI/cice5/blob/master/doc/cicedoc.pdf)). For one degree resolution models, this can be easily achieved by scaling _blckx_ inversely with the number of processes—for example, if the process count is halved, double _blckx_. In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes. Finally, in the `config.yaml`, change the executable name to the new build and change `ice: ncpus` to the desired number of processes.
+- **CICE5**
+    - In `spack.yaml`, modify or add the [five variants `nxglob`, `nyglob`, `blckx`, `blcky`, `mxblcks`](https://github.com/search?q=repo%3AACCESS-NRI%2Faccess-spack-packages+%5C%22nxglob%5C%22+%5C%22nyglob%5C%22+%5C%22blckx%5C%22+%5C%22blcky%5C%22+%5C%22mxblcks%5C%22&type=code) to the desired number of processes and blocks (for details, see Section 4.7 of [CICE5 documentation](https://github.com/ACCESS-NRI/cice5/blob/master/doc/cicedoc.pdf)). For one degree resolution models, this can be easily achieved by scaling `blckx` inversely with the number of processes (for example, if the process count is halved, double the value of `blckx`).
+    - In the configuration's `ice/cice_in.nml`, change `nprocs` in the `&domain_nml` namelist to the desired number of processes.
+    - In the `config.yaml`, change the executable name to the new build and change `ice: ncpus` to the desired number of processes.

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