This folder contains examples showcasing the usage of the PyLammps 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 PyLammps tutorial.

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

Clone the LAMMPS source code

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

Create a build folder
```
$ mkdir build
$ cd build
```
Create a virtual environment for Python
```
$ python3 -m venv myenv
```

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

Activate the virtual environment
```
$ source myenv/bin/activate
(myenv)$
```

Configure LAMMPS compilation (CMake)

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

Compile LAMMPS
```
(myenv)$ cmake --build .
```
Install LAMMPS and Python package into virtual environment
```
(myenv)$ cmake --install .
```
Install other Python packages into virtual environment
```
(myenv)$ pip install jupyter matplotlib mpi4py
```

Navigate to pylammps examples folder

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

Launch Jupyter and work inside browser
```
(myenv)$ jupyter notebook
```