Usage¶

Access¶

The ICON repository is hosted on the C2SM GitHub organisation. If you do not have access, please follow the instructions under How to get Access.

If you do not already have an SSH key set up for GitHub, but would like to do so, follow the instructions .

Configure and compile¶

Säntis¶

Under construction - last update: 2025-02-18

Information on this section is not yet complete nor final. It will be updated following the progress of the Alps system deployment at CSCS and C2SM's adaptation to this new system. Please use the C2SM support forum in case of questions regarding building ICON on Alps.

ICON at C2SM¶

Clone the ICON repository on the branch santis:

git clone -b santis --recurse-submodules git@github.com:C2SM/icon.git

Run the following after navigating into ICON root folder:

# Load ICON user-environment 
uenv start icon-wcp/v1:rc4

# Setup spack
SPACK_TAG=$(cat "config/cscs/SPACK_TAG_ALPS")
git clone --depth 1 --recurse-submodules --shallow-submodules -b ${SPACK_TAG} https://github.com/C2SM/spack-c2sm.git
. spack-c2sm/setup-env.sh /user-environment

# Build ICON
# For out-of-source builds: navigate into the build folder and adapt the path to the Spack environment in the following
spack external find gmake
spack env activate -d config/cscs/spack/${SPACK_TAG}/santis_gpu_nvhpc
spack install

ICON-NWP¶

Clone the ICON-NWP repository (only possible if you have access to GitLab DKRZ):

git clone --recurse-submodules git@gitlab.dkrz.de:icon/icon-nwp.git

1. Create a spack.yaml file

Create the following files from the ICON build folder (different to the ICON root folder in case of a out-of-source build). For that, you will have to create the missing folders first:

SPACK_TAG=$(cat "config/cscs/SPACK_TAG_ALPS")
mkdir -p config/cscs/spack/${SPACK_TAG}/santis_cpu_nvhpc
mkdir -p config/cscs/spack/${SPACK_TAG}/santis_gpu_nvhpc

For CPU compilation:

config/cscs/spack/${SPACK_TAG}/santis_cpu_nvhpc/spack.yaml

spack:
  specs:
    - gmake%gcc
    - gnuconfig%gcc
    - cosmo-eccodes-definitions@2.25.0.2
    - icon @develop %nvhpc +grib2 +eccodes-definitions +ecrad ~emvorado +art +dace
      +realloc-buf ~aes ~jsbach ~ocean ~coupling ~rte-rrtmgp
      ~loop-exchange ~async-io-rma
  view: true
  concretizer:
    unify: true
  develop:
    icon:
      path: ../../../../..
      spec: icon @develop %nvhpc +grib2 +eccodes-definitions +ecrad ~emvorado +art
        +dace +realloc-buf ~aes ~jsbach ~ocean
        ~coupling ~rte-rrtmgp ~loop-exchange ~async-io-rma

For GPU compilation:

config/cscs/spack/${SPACK_TAG}/santis_gpu_nvhpc/spack.yaml

spack:
  specs:
    - gmake%gcc
    - gnuconfig%gcc
    - cosmo-eccodes-definitions@2.25.0.2
    - icon @develop %nvhpc +grib2 +eccodes-definitions +ecrad ~emvorado +art +dace
      gpu=openacc+cuda +mpi-gpu +realloc-buf ~aes ~jsbach ~ocean ~coupling ~rte-rrtmgp
      ~loop-exchange ~async-io-rma ~pgi-inlib +cuda-graphs
  view: true
  concretizer:
    unify: true
  develop:
    icon:
      path: ../../../../..
      spec: icon @develop %nvhpc +grib2 +eccodes-definitions +ecrad ~emvorado +art
        +dace gpu=openacc+cuda +mpi-gpu +realloc-buf ~aes ~jsbach ~ocean
        ~coupling ~rte-rrtmgp ~loop-exchange ~async-io-rma ~pgi-inlib +cuda-graphs

2. Build ICON

Run the following after navigating into the ICON-NWP root folder:

# Load ICON user-environment
uenv start icon-wcp/v1:rc4

# Setup spack
SPACK_TAG=$(cat "config/cscs/SPACK_TAG_ALPS")
git clone --depth 1 --recurse-submodules --shallow-submodules -b ${SPACK_TAG} https://github.com/C2SM/spack-c2sm.git
. spack-c2sm/setup-env.sh /user-environment

# Build ICON
# For out-of-source builds: navigate into the build folder and adapt the path to the Spack environment in the following
spack external find gmake
spack env activate -d config/cscs/spack/${SPACK_TAG}/santis_gpu_nvhpc
spack install

Euler¶

Clone the ICON repository on the main branch:

git clone --recurse-submodules git@github.com:C2SM/icon.git

Load the necessary modules:

module load stack eth_proxy

The module stack provides the software stack, including gcc/12.2.0. The module eth_proxy enables the connection from a compute node to an external service, e.g. GitHub or GitLab.

Run the following after navigating into ICON root folder:

# Setup spack
SPACK_TAG=$(cat "config/ethz/SPACK_TAG_EULER")
git clone --depth 1 --recurse-submodules --shallow-submodules -b ${SPACK_TAG} https://github.com/C2SM/spack-c2sm.git
. spack-c2sm/setup-env.sh

Euler Support recommends to compile code on compute nodes. There, we can take advantage of multi-core compiling:

# Build ICON
# For out-of-source builds: navigate into the build folder and 
# adapt the path to the Spack environment in the following
spack env activate -d config/ethz/spack/${SPACK_TAG}/euler_cpu_gcc
srun -N 1 -n 12 --mem-per-cpu=1G spack install -j 12

Run test case¶

In the run folder, you find many prepared test cases, which you can convert into run scripts. To generate the runscript of one of the experiment files, e.g. mch_ch_lowres, you can use the make_runscripts function.

./make_runscripts mch_ch_lowres

To run the created runscript, navigate to the run subdirectory and submit the runscript.

cd run && sbatch ./exp.mch_ch_lowres.run

You may need to adjust the account in the runscript to match your permissions. Alternatively, you can include --account=<my_account_id> in the sbatch command.

Info

The data pool on santis is currently not in a persistent location, and you may not have access privileges. Therefore, you may not be able to run the test cases at this time. As soon as this is fixed, we will update this page accordingly.

Input data¶

The input data for standard ICON tests are stored in a Git-lfs repository .

Input data pools¶

SantisEulerBalfrin

/capstor/store/cscs/userlab/d126/pool/data/ICON/

/cluster/work/climate/icon_input

/scratch/mch/jenkins/icon/pool/data/ICON