This folder contains examples showcasing the usage of the LAMMPS Python interface and Jupyter notebooks. To use this you will need LAMMPS compiled as a shared library and the LAMMPS Python package installed.

An extensive guide on how to achieve this is documented in the LAMMPS manual. There is also a LAMMPS Python tutorial.

The following will show one way of creating a Python virtual environment which has both LAMMPS and its Python package installed:

1. Clone the LAMMPS source code

   $ git clone -b stable https://github.com/lammps/lammps.git
   $ cd lammps

2. Create a build folder

   $ mkdir build
   $ cd build

3. Create a virtual environment for Python

   $ python3 -m venv myenv

4. Extend LD_LIBRARY_PATH (Unix/Linux) or DYLD_LIBRARY_PATH (MacOS)

   On Unix/Linux:

   $ echo 'export LD_LIBRARY_PATH=$VIRTUAL_ENV/lib:$LD_LIBRARY_PATH' >> myenv/bin/activate

   On MacOS:

   echo 'export DYLD_LIBRARY_PATH=$VIRTUAL_ENV/lib:$DYLD_LIBRARY_PATH' >> myenv/bin/activate

5. Activate the virtual environment

   $ source myenv/bin/activate
   (myenv)$

6. Configure LAMMPS compilation (CMake)

   (myenv)$ cmake -C ../cmake/presets/basic.cmake \
                  -D BUILD_SHARED_LIBS=on \
                  -D PKG_PYTHON=on \
                  -D CMAKE_INSTALL_PREFIX=$VIRTUAL_ENV \
                  ../cmake

7. Compile LAMMPS

   (myenv)$ cmake --build .

8. Install LAMMPS and Python package into virtual environment

   (myenv)$ make install-python

9. Install other Python packages into virtual environment

   (myenv)$ pip install jupyter matplotlib pandas mpi4py

10. Navigate to ipython examples folder

    (myenv)$ cd ../python/examples/ipython

11. Launch Jupyter and work inside browser

    (myenv)$ jupyter notebook