Cluster Expansion in Atomic Simulation Environment (CLEASE)

Cluster expansion (CE) is a widely used method for studying thermondynamic properties of disordered materials. CLEASE is a cluster expansion code which strives to be highly flexible and customizable, which also offering a wide range of useful tools, such as:

and much more. A tutorial of how to use CLEASE can be found in our AuCu example.


Most of the standard CE routines can be performed using the graphical user interface (GUI). The CLEASE GUI is an app based on the jupyter notebook. Please remember to report any issues to the developers.


A latest stable version of CLEASE can be installed using the following command

pip install clease

Installation can also be done through conda via the conda-forge project:

conda install -c conda-forge clease


On Windows, we recommend installing CLEASE with conda, in order to simplify the compilation process.

Alternatively, you can install the latest development version of CLEASE by following the instructions in the README page.


The method and implementation details of CLEASE are described in the following publication:

J. Chang, D. Kleiven, M. Melander, J. Akola, J. M. Garcia-Lastra and T. Vegge
Journal of Physics: Condensed Matter