PyStan 3 Beta 3 Released

PyStan 3 Beta 3 is now available on PyPI for macOS and Linux users. Documentation:

Installation: python3 -m pip install --pre pystan

New in PyStan 3 Beta 3:

  • Model compilation is ~30% faster.
  • Better cache management.
  • Stanc warnings shown (--warn-pedantic is set).

New in PyStan 3 Beta series:

  • Automatic caching of compiled Stan models
  • Automatic caching of samples from Stan models
  • Open source software: ISC License
  • Stan 2.24
  • CVODES support out of the box.


  • macOS or Linux.
  • Python 3.7 or higher.

Upgrading to PyStan 3 from PyStan 2:

There are many backwards-incompatible changes in PyStan 3.0.
Upgrading to Newer Releases summarizes the changes.

Known issues:

  • Only the recommended sampler (No-U-Turn Sampler) is currently supported.
  • Windows is not supported at this time.
  • Linux users with older operating systems may have problems using wheels from PyPI. Ubuntu 20.04 and Debian Bullseye should work. Users with an older version of GCC or Clang need to install httpstan from source before installing pystan.