The in.kokkos input script is a copy of the bench/in.lj script, but can be run with the KOKKOS package,

To run it, you must first build LAMMPS with the KOKKOS package installed, following the steps explained in Section 2.3.4 of doc/Section_start.html. An overview of building and running LAMMPS with the KOKKOS package, for different compute-node hardware on your machine, is given in Section 5.8 of doc/Section_accelerate.html.

The example log files included in this directory are for a desktop box with dual hex-core CPUs and 2 GPUs.

Two executables were built in the following manner:

make yes-kokkos make g++ OMP=yes -> lmp_cpu make cuda CUDA=yes -> lmp_cuda

Then the following runs were made. The "->" means that the run produced log.lammps which was then copied to the named log file.

• MPI-only runs

lmp_cpu -k off < in.kokkos -> log.kokkos.date.mpionly.1 mpirun -np 4 lmp_cpu -k off < in.kokkos -> log.kokkos.date.mpionly.4

• OpenMP threaded runs on CPUs only

lmp_cpu -k on t 1 -sf kk < in.kokkos.half -> log.kokkos.date.cpu.1 lmp_cpu -k on t 4 -sf kk < in.kokkos -> log.kokkos.date.cpu.4

Note that in.kokkos.half was use for one of the runs, which uses the package command to force the use of half neighbor lists which are faster when running on just 1 thread.

• GPU runs on 1 or 2 GPUs

lmp_cuda -k on t 6 -sf kk < in.kokkos -> log.kokkos.date.gpu.1 mpirun -np 2 lmp_cuda -k on t 6 -sf kk < in.kokkos -> log.kokkos.date.gpu.2

Note that this is a very small problem (32K atoms) to run on 1 or 2 GPUs.