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This is the Wiki for CmdStanPy, a lightweight interface to Stan for Python users.

• CmdStanPy is implemented in Python3

• CmdStanPy uses numpy ndarrays and pandas DataFrames

• It requires a local install of CmdStan, which in turn requires a working C++ toolchain.

Developers

We welcome contributions! Contributions should follow the general outlines of the Stan Developer Process

• GitHub issues are used to discuss both bugs and features and propose implementations.

• Additions and changes to the code base should include updates to unit tests. User-facing changes require updates to the documentation as well.

• The GitHub repo organization follows the gitflow model described by Vincent Driessen in the blog post "A successful Git branching model.". The main developer branch is develop; it should always be runnable.

• Unit tests must be runnable under both the unittest and PyTest frameworks. See https://github.com/stan-dev/cmdstanpy/blob/develop/requirements-test.txt for the complete list of packages needed to run the unit tests.

• Code should follow standard formatting conventions and provide type hints for all variables. To adhere to formatting standards, we recommend using tools black and isort. The following code-checker tools are used:

  • Flake8 checks code style and formatting
  • PyLint checks formatting and many additional checks. See PyLint configuration file and https://github.com/stan-dev/cmdstanpy/blob/a6e09190af555aa6d05993d630ebf39a3d4bb867/.travis.yml#L30
  • MyPy is a static type checker

Documentation

CmdStanPy uses Sphinx to generate the docs.

• Documentation src files live in directory docsrc

• The documentation is hosted on readthedocs as https://cmdstanpy.readthedocs.io, which provides documentation for all tagged releases.

  • The stable branch is the most recent tagged version

  • The latest branch is the current develop branch

  • Readthedocs automation rules are used to generate docs for new tags.

• The current develop branch docset in the docs directory is hosted by GitHub pages as https://mc-stan.org/cmdstanpy The Sphinx makefile docsrc/Makefile target github is used to update the contents of the docs directory.

• Packages used to build the docs are listed in https://github.com/stan-dev/cmdstanpy/blob/develop/docsrc/env.yml