Installation¶

The recommended way to install MaxwellLink is through a conda environment that provides third-party EM solvers and molecular drivers.

Recommended Installation Option¶

Prerequisites¶

A recent Python (>=3.9).
A working MPI stack (e.g. MPICH or OpenMPI) whenever you plan to run MaxwellLink under mpirun.
C/Fortran toolchains supplied by your platform if you plan to build drivers such as LAMMPS from source.

Create a conda environment¶

# Create a fresh conda environment for MaxwellLink
CONDA_ENV="mxl"
conda create -n "$CONDA_ENV" python=3.13
conda activate "$CONDA_ENV"

Install MaxwellLink¶

pip install maxwelllink

This installs the MaxwellLink package with the necessary dependencies.

Optional EM solvers¶

Currently, MaxwellLink ships with Meep and a simple single-mode cavity solver. While the built-in single-mode cavity is mainly for prototyping and debugging, Meep is a full-featured FDTD package suitable for production simulations. One can install Meep with MPI support via conda:

conda install -c conda-forge pymeep="*=mpi_mpich_*"

Note

Users can also install Meep from source following the official instructions.

Optional driver dependencies¶

A two-level system (TLS) model ships with MaxwellLink and does not require extra packages. Beyond this lightweight driver, MaxwellLink supports several molecular drivers that depend on third-party packages. Install any molecular drivers below that you want to use. Each molecular driver can be pulled into the same conda environment.

# Model Hamiltonians via QuTiP
conda install -c conda-forge qutip

# Psi4 for RT-TDDFT and Ehrenfest drivers
conda install -c conda-forge psi4

# Atomic Simulation Environment (ASE) for classical/MM drivers
conda install -c conda-forge ase

# LAMMPS driver with fix mxl (installs a custom binary lmp_mxl)
mxl_install_lammps

The LAMMPS helper downloads and builds a modified LAMMPS executable that contains fix mxl; alternatively copy the provided fix_maxwelllink.cpp and fix_maxwelllink.h files in source code (src/maxwelllink/mxl_drivers/lammps/) into your existing LAMMPS build and recompile.

Install MaxwellLink from source¶

In the same conda environment, if you would like to explore or contribute to MaxwellLink, clone the repository and install the package:

git clone https://github.com/TaoELi/MaxwellLink.git
cd MaxwellLink
pip install .

Enter the developer mode¶

Install developer dependencies to set up a development environment:

pip install ".[dev]"

Testing and Validation¶

After contributing to the code, add a test file in the tests/ folder and run the test suite to ensure everything works as expected.

Use pytest to run the tests. From the root directory of the repository, run:

# Run the fast tests (TLS under socket/non-socket modes)
pytest -m core -v

# Run the optional Psi4 and QuTiP tests when the dependencies are available
pytest -m "optional or slow" -v

If the optional tests are skipped, confirm that the corresponding packages were installed or adjust your PYTHONPATH so that the drivers can import them.

Build the Documentation¶

The documentation can be built locally. Use the optional docs extra to install the Sphinx toolchain:

pip install ".[docs]"

Then generate the API and HTML pages using Sphinx and open them in your default browser:

make doc html