lammps/examples/kokkos

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 (non-KOKKOS) runs

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