The Kokkos package version of ReaxFF will be in the LAMMPS git and svn repositories tomorrow (Friday June 24), and a patch will follow soon. Beta testers are welcome to try it out. Much of the credit goes to Ray Shan (now at Materials Design, Inc.).
Some advantages of Kokkos ReaxFF are that it can run using OpenMP threads and on GPUs and it is designed to be more memory robust that pair reax/c. In some cases it is also slightly faster than pair reax/c for MPI only if you use the “neigh half” Kokkos package option and build with /src/MAKE/OPTIONS/Makefile.kokkos_mpi_only.
Please report any issues to the mail list.