The auxiliary-field quantum Monte Carlo package ALF [1, 2] is a powerful tool for simulating a broad set of fermionic systems, but since it is written in Fortran, it is not very dynamic and can be a bit daunting for new users.

Aiming to address this challenge, pyALF is a set of Python scripts built on top of ALF. It is meant to simplify the different steps of working with ALF, including:

  • Obtaining and compiling the ALF source code

  • Preparing and running simulations

  • Postprocessing and displaying the data obtained during the simulation

The source codes for both ALF and pyALF are publicly available at

This documentation is structured in the following way:

  1. Prerequisites and installation describes the prerequisites of pyALF and how to set things up to be able to use it in a productive manner.

  2. Usage displays the features of pyALF and how to use them on small examples.

  3. For a reference on pyALF’s features, see Reference.