Python library and command line tool for calculation of free energies.


  • lammps 2021.05.27

  • mendeleev 0.7.0 pip install mendeleev

  • pylammpsmpi 0.0.8 pip install pylammpsmpi

  • pyscal 2.10.14 pip install git+

  • pyyaml 5.4.1 pip install pyyaml

  • scipy 1.7.0 pip install scipy

  • tqdm 4.61.2 pip install tqdm


  • matplotlib 3.4.2 pip install matplotlib

  • pytest 6.2.4 pip install pytest


NOTE: If you are planning to use a custom version of LAMMPS, read the ‘Notes on the LAMMPS installation’ section first.

It is strongly recommended to install and use calphy within a conda environment. To see how you can install conda see here.

Once a conda distribution is available, the following steps will help set up an environment to use calphy. First step is to clone the repository.

git clone

After cloning, an environment can be created from the included file-

cd calphy
conda env create -f environment.yml

This will install the necessary packages and create an environment called calphy. It can be activated by,

conda activate calphy

then, install calphy using,

python install --user

The environment is now set up to run calphy.

Notes on the LAMMPS installation

NOTE: 08 July 2021: The upcoming release of LAMMPS will significantly change the compilation procedure and render the below information outdated.

  • The above commands will install LAMMPS from the conda-forge channel. With this version of LAMMPS, only eam pair style is supported!

  • For other pair styles such as Stillinger-Weber, MEAM, ADP, and SNAP, a custom version of LAMMPS is available. Please contact here.

  • For using with pair style PACE, the LAMMPS distribution has to be compiled manually:

tar -xvf stable_29Oct2020.tar.gz
cd lammps-stable_29Oct2020
mkdir build_lib
cd build_lib
make # -j${NUM_CPUS}
cp liblammps${SHLIB_EXT}* ../src

If the commands are run within a conda environment and errors during compilation are observed, try installing the following packages:

conda install -c conda-forge cmake gcc_linux-64 gxx_linux-64 gfortran_linux-64

Now the python wrapper can be installed:

cd ../src
make install-python

In the case of a conda environment, the following commands can be used to copy the compiled libraries to an accessible path:

mkdir -p $CONDA_PREFIX/include/lammps
cp library.h $CONDA_PREFIX/include/lammps
cp liblammps${SHLIB_EXT}* $CONDA_PREFIX/lib/

The combined libraries should be available on the system or the environment paths. Please see here for more details.

Once LAMMPS is compiled and the libraries are available in an accessible location, the following commands can be used within python to test the installation:

from lammps import lammps
lmp = lammps()