Contributing to libEnsemble

Contributions may be made via a GitHub pull request to

libEnsemble uses the Gitflow model. Contributors should branch from, and make pull requests to, the develop branch. The main branch is used only for releases. Pull requests may be made from a fork, for those without repository write access.

Code should pass flake8 tests, allowing for the exceptions given in the flake8 file in the project directory. Python code should be formatted using the latest version of black by running the following in the base libensemble directory:

black .

Issues can be raised at

Issues may include reporting bugs or suggested features. Administrators will add issues, as appropriate, to the project board at

By convention, user branch names should have a <type>/<name> format, where example types are feature, bugfix, testing, docs, and experimental. Administrators may take a hotfix branch from the main, which will be merged into main (as a patch) and develop. Administrators may also take a release branch off develop and then merge this branch into main and develop for a release. Most branches should relate to an issue or feature.

When a branch closes a related issue, the pull request message should include the phrase “Closes #N,” where N is the issue number. This will automatically close out the issues when they are pulled into the default branch (currently main).

libEnsemble is distributed under a 3-clause BSD license (see LICENSE). The act of submitting a pull request (with or without an explicit Signed-off-by tag) will be understood as an affirmation of the following:

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.