FAQ#

Configuring and Building#

  1. I run the configure script without any arguments and it fails. What should I do?

    First, we recommend checking whether there is a suitable Configure wrappers in the config directory that you could use instead of running the configure script directly. If that is not the case, you need at least to specify the LIBS variable telling the configure script which libraries to link the executables to. The content of the list depends on the configure options you specify (see Table 1), for example:

    ./configure --disable-mpi --disable-coupling LIBS='-lnetcdff -lnetcdf -llapack'

    If the libraries reside in nonstandard directories, you might also need to specify the FCFLAGS, CPPFLAGS, and LDFLAGS variables to tell the script which directories need to be searched for header and library files (see section Configuration) for more details).

  2. How can I reproduce the configuration of the model used in a Buildbot test?

    Scripts run by Buildbot for configuration and building of the model reside in the config/buildbot directory. You can run them manually on the corresponding machine.

  3. I get an error message from the configure script starting with “configure: error: unable to find sources of…”. What does this mean?

    Most probably, you forgot to initialize and/or update git submodules. You can do that by switching to the source root directory of ICON and running the following command:

    git submodule update --init

  4. I have problems configuring/building ICON. What is the most efficient way to ask for help?

    Whoever you ask for help will appreciate receiving the log files. You can generate a tarball with the log files by running the following commands from the root build directory of ICON:

    make V=1 2>&1 | tee make.log
tar --transform 's:^:build-report/:' -czf build-report.tar.gz $(find . -name 'config.log' -o -name 'CMakeCache.txt') make.log

    The result of the commands above will be file build-report.tar.gz, which should be attached to the very first email describing your problem. Please, do not forget to specify the repository and the branch that you experience the issue with, preferably in the form of a URL (e.g. https://gitlab.dkrz.de/icon/icon-model/-/tree/icon-2026.04-public).

Running#

  1. A simulation is not behaving in the way I expected, any advice to start troubleshooting?

    • Make sure that namelist names are correctly written in the runscript (ICON skips misspelled namelists and continues the run without exiting).

Output#

  1. How can I find the available output variables of a configuration?

    Set msg_level=15 (or larger) in the &run_nml namelist to print all available “ICON short names” of output variables for the current configuration in the logfile.

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