## 1. Download LAMMPS Follow the instructions at [LAMMPS GitHub Installation Guide](https://docs.lammps.org/Install_git.html). ```bash git clone -b release https://github.com/lammps/lammps.git mylammps ``` ## 2. Install Open MPI Follow the quickstart guide at [Open MPI Installation Guide](https://docs.open-mpi.org/en/v5.0.x/installing-open-mpi/quickstart.html). Ensure you add the installed directory to your `PATH`. ## 3. Build and Install LAMMPS ### Build LAMMPS 1. Use CMake to generate a build environment in a new directory. 2. Compile and link all objects, libraries, and executables using the selected build tool. ```bash cd lammps # Change to the LAMMPS distribution directory mkdir build; cd build # Create and use a build directory # Configuration reading CMake scripts from ../cmake cmake -D BUILD_MPI=yes -D LAMMPS_MACHINE=mpi -D PKG_MANYBODY=yes -D PKG_REPLICA=yes -D PKG_H5MD=yes -C ../cmake/presets/most.cmake ../cmake cmake --build . # Compilation (or type "make") ``` > **Note:** If you encounter an error during the build process, remove `CMakeCache.txt` before building again. ### Install LAMMPS After compilation, install the LAMMPS executable: ```bash make install # Optional, copies compiled files into the installation location ``` ## 4. Test LAMMPS Run a test simulation to ensure LAMMPS is installed correctly: ```bash cd lammps/examples/indent/ lmp_mpi -in ./in.indent ``` To test MPI, ```bash mpirun -np <number_of_processors> lmp_mpi -in ./in.indent ``` Replace `<number_of_processors>` with the number of processors you want to use for the test.