report bugs & request features

Report a Bug

Bugs in Stan, its interfaces, or its documentation may be reported through the appropriate interface-specific issue tracker. Installation issues should be discussed on the users group.

To report a bug, first read the instructions below; then select an interface to find the link to the appropriate issue tracker.

How to Report Bugs

The key to a successful bug report is to provide as much context as possible, ideally in the form of a small reproducible example. The more of the following you include, the easier it will be for us to help you:

  • a description of what you were trying to do,
  • call to Stan that caused the bug,
  • the complete Stan program,
  • the complete error message,
  • Stan version and Stan interface version,
  • host language version if applicable (e.g., R or Python)
  • operating system and version,
  • C++ compiler and version.

For R users, much of this information is reported within R by sessionInfo().

Request Features

We’re happy to field feature requests from users. Feature requests can be for new functions to support, new samplers, support for platforms, etc. Please provide as much information as possible, including links to papers or formulas.

Feature requests should be made either on the users group or using the issue tracker for the appropriate interface.

Submit Bug Fixes or Enhancements

We are grateful to accept bug fixes or enhancements to the documentation or code or example models.

GitHub Pull Requests

Patches to Stan are managed through GitHub pull requests; specifically requests to merge into the current develop branch.

Code authors maintain copyright, but must agree to release all submitted patches under the open-source license for the interface being patched.