GEOS-Chem coding and debugging
On this page we provide information about GEOS-Chem coding and debugging, as well as the procedure by which new features are added.
How GEOS-Chem Code Development works
The GEOS-Chem Steering Committee (GCSC) encourages updates to the GEOS-Chem model. Updates to the GEOS-Chem model benefit both the developer and the entire GEOS-Chem community. The developer benefits through coauthorship and citations. Priority development needs are identified at GEOS-Chem users' meetings with updates between meetings based on GCSC input through working groups.
When should you submit updates to the GEOS-Chem code? Bug fixes should be submitted as soon as possible and will trump all other priorities. Code related to model developments should be submitted when it is mature. Your working group chair can offer guidance on the timing of submitting code to the GCST.
Submitting updates for inclusion into GEOS-Chem
- Create or log into your GitHub account.
- Fork the GEOS-Chem repositories. Navigate to each appropriate GEOS-Chem repository on GitHub and click Fork in the top-right corner of the page.
- Clone your forks of the GEOS-Chem repositories to your system (e.g. git clone https://github.com/YOUR-USERNAME/geos-chem Code.12.0.0; git clone https://github.com/YOUR-USERNAME/geos-chem-unittest UT.12.0.).
- Add your modifications into a new branch off of the master branch.
- Test your update thoroughly and make sure that it works.
- You can use the GEOS-Chem Unit Tester to make sure your code updates work for a given combination of met fields, resolutions, and simulation types. A unit test looks for parallelization errors, floating point math issues, array-out-of-bounds errors, and creation of array temporaries.
- For structural updates, we recommend running difference tests often to ensure your updates don't impact model output.
- Review the code update checklist and data checklist below.
- Contact your Working Group leaders to request that your changes be included in the standard code.
- Create a pull request in GitHub (recommended) or a Git patch file.
- Fill out and submit the GEOS-Chem Update Submission Form.
- The GEOS-Chem Steering Committee will meet every three months and set the GEOS-Chem model development priorities (i.e. decide on the order in which updates will be added to GEOS-Chem).
- The GEOS-Chem Support Team will add your changes to the standard code. Your update may be bundled with other code updates and the GEOS-Chem version number (X.Y.Z) will be changed. The update will be validated following the GEOS-Chem benchmarking procedure.
Checklist for code update submissions
- Use F90 free format whenever possible
- Include thorough comments throughout code updates
- Remove extraneous code updates (e.g. testing options, other science)
- Include full citations at the top of relevant source code modules
- Complete GCHP updates required with GEOS-Chem Classic updates
Checklist for data submissions
- Make sure data files are COARDS-compliant
- Use isCoards script and include output in submission
- Include updated HEMCO_Configuration file (if the data will be read via HEMCO). Submit this as a pull request in the geos-chem-unittest repository on GitHub.
- Include README file detailing data source, contents, etc.
- Include script(s) used to process original data
- Include a summary or description of the expected results (e.g. emission totals for each species)
- Developing GEOS-Chem
- Developing GCHP
- Programming techniques for HPC environments
- Derived type objects used by GEOS-Chem