How to contribute#

Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.

Get Started!#

Ready to contribute? Here’s how to set up zfit for local development.

  1. Fork the zfit repo on GitHub.

  2. Clone your fork locally:

git clone
  1. Install your local copy into a conda/mamba or other virtual environment. For example with conda, do

conda create -n zfit311 python=3.11
conda activate zfit311
pip install -e .[alldev]  # . is the folder where is

Further, you can install pre-commit locally to run the checks before you commit:

pip install pre-commit
pre-commit install  # this will execute pre-commit checks before every commit
  1. Create a branch for local development

 git checkout -b name-of-your-bugfix-or-feature

Now you can make your changes locally.
  1. When you’re done making changes, check that your changes pass the tests (this can take a while ~30 mins). You can run the tests in parallel by installing pytest-xdist and running pytest -n NUM where NUM is the number of cores

pytest  # in the root folder of the repository where tests folder is

(Some tests have a @flaky decorator, which means that they might fail sometimes. If you see a flaky test failing, inspect it, but most likely it’s not a problem with your changes. Rerunning the specific test usually solves the problem.)

Some elements, like objects that can be dumped to HS3, new PDFs etc, have a truth. This is a reference file and test that check against such a file are therefore expected to fail (as the truth file doesn’t exist yet). To create/regenerate a truth file, run the specific test that uses a truth file with the option --recreate-truth after you verified that the output is actually correct.

For example, to run the test test_dumpload_hs3_pdf in file tests/serialize/, run

pytest tests/serialize/ -- --recreate-truth
  1. Commit your changes and push your branch to GitHub

git add .
git commit -m "Your detailed description of your changes."
git push origin name-of-your-bugfix-or-feature
  1. Submit a pull request through the GitHub website. The test suite is going to run again, testing all the necessary Python versions.

Pull Request Guidelines#

Before you submit a pull request, check that it meets these guidelines:

  1. The pull request should include tests.

  2. If the pull request adds functionality, the docs may need to be updated. Put your new functionality into a function with a docstring (and add the necessary explanations in the corresponding rst file in the docs). If any math is involved, please document the exact formulae implemented in the docstring/docs. New elements, such as a new PDF, should for example be added to the docs/user_api/pdf/suitable_file.rst.