PyStan 3 Beta 5 Released

PyStan 3 Beta 5 is now available on PyPI for macOS and Linux users. Documentation:

Installation: python3 -m pip install --pre pystan

New in PyStan 3 Beta 5:

  • Fix for macOS.

New in PyStan 3 Beta series:

  • Automatic caching of compiled Stan models
  • Automatic caching of samples from Stan models
  • Open source software: ISC License
  • CVODES support out-of-the-box.
  • Timely releases. PyStan 3 releases tend to arrive 30 hours after Stan releases (n = 1).


  • 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.
  • Recent Linux version required. 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.
  • PyStan 3 does not work in a Jupyter Notebook due to a bug in Jupyter Notebook. A workaround exists, Using PyStan 3 with Jupyter Notebook and Jupyterlab

What is the minimum version of GCC required to use PyStan 3?

Stan requires GCC version 4.9 or greater

A recent gcc would be best. If you’re on Linux and you want to use the pre-compiled wheels, you need a very recent version, gcc 9 or higher. (There are some libc++ ABI issues with older versions.)

But any version equal to or higher than 4.9 should work if you compile from source.