PyRosetta is an interactive Python-based interface to Rosetta, allowing users to create custom molecular modeling algorithms with Rosetta sampling and scoring functions using Python scripting. PyRosetta was written for Python 2.6, while the newer PyRosetta-4 also works with Python 3+

PyRosetta is available as a separate download (independent of C++ Rosetta). See for more details. If you are a developer, it can also be compiled from source.

Quick Start Guide for Linux/OS X

Note: Python 2.6 or better is required. Python 3 now works with the PyRosetta-4 version of PyRosetta.

  1. Obtain a license for PyRosetta.
  2. Either download a copy of PyRosetta or checkout the repository.
    1. Download a copy of PyRosetta from here.
      • Extract said copy with $ tar -vjxf PyRosetta-<version>.tar.bz2. Everything to run PyRosetta is contained within this directory.
    2. Alternatively, if you have a RosettaCommons GitHub account, you can checkout a PyRosetta repository (updated weekly) by running $ git clone http://login@git-repository-address. For example, to get the OS X namespace (see below for monolith vs. namespace) build one would run:
      $ git clone


  1. From the main PyRosetta directory, run python install

  2. Be aware that running PyRosetta is now different than for PyRosetta-3: See below.

    from rosetta import *
    from pyrosetta import *
    rosetta.init("-list -of -options")


  1. From within the main PyRosetta directory, run $ source or append it to your .bashrc file and source that.
  2. Test your PyRosetta installation by running the line import rosetta; rosetta.init() in Python. Output should be about the PyRosetta version and random seed.
    • Exiting the PyRosetta directory prior to running Python should help avoid path issues or confirm that your path is properly set.

Quick Start Guide for Windows

Note: Windows is seldom supported in the Rosetta community. Requires Python 2.7.

  1. Obtain a license for PyRosetta.
  2. Download and unzip a copy of PyRosetta from here.
  3. Test your PyRosetta installation by running the line import rosetta; rosetta.init() in Python. Output should be about the PyRosetta version and random seed.

PyRosetta-3 Namespace vs. monolith: According to Sergey, in the namespace build each C++ namespace has its own shared library which the kernel needs to load, resolve symbols, and so on. Hence, importing in the namespace build is IO heavy, but memory light. The monolith build on the other hand, has all the C++ namespaces defined in a single C++ library. For example, importing rosetta (via PyRosetta) in the namespace build on Stampede (NFS with high latency) could take up to 20 minutes. Doing the same with the monolith build would require about 7 seconds. The current recommendation is namespace for machines with memory constraints (e.g. less than 4 GB per thread) or for local development. For production runs on clusters (typically using the NSF filesystem), use monolith.

PyRosetta-4 Namespace vs monolith: Monolith version is the only PyRosetta-4 version. This monolith takes up a very small memory footprint as compared to PyRosetta-3 monolith version, as well as numerous other improvements.

Additional Documentation

More extensive PyRosetta-specific documentation is available:

A general overview of the general Rosetta object structure and organization can be found here:

The PyRosetta Toolkit

The PyRosetta Toolkit GUI is a graphical frontend to PyRosetta written in Python. A Tutorial and overview of the code base and how to extend it for your own uses can be found here.

Note that currently, the PyRosetta Toolkit and other published apps only distributed with PyRosetta-3

See Also