I was trying to run a very simple LAMMPS input file (attached) for a UO2 lattice with an oxygen vacancy.
The potential parameters are correct.
With the exact same input file, I submitted 3 different LAMMPS jobs: 1. regular LAMMPS run, 2. with USER-OMP enabled, 3. with Kokkos OpenMP enabled.
For the first 2 cases (regular, and USER-OMP), the job finished without any error. But, the Kokkos run was terminated with an error message: “Non-numeric pressure - simulation unstable”. Pressure became large negative, so division by a large number producing NaN, probably!
Okay, it implies instability in one or more input parameters (though I am pretty sure input potential params are correct). I changed the npt input parameters (mainly the pressure related) a bit, no change!
But, why is this selective to Kokkos only?
I am just concerned if the input is “meaningless”, it should produce error for the regular as well as the USER-OMP versions too, not only the Kokkos version. Either it will produce error for all of the above runs, or it would be all running okay: It should not be selective.
Input file and output for all of the above runs are attached herewith.
I tried with both LAMMPS 2019 & 2020 versions, Intel 2019u5, MKL.
Could there be a bug?
output-kokkos.txt (25.1 KB)
output-regular.txt (3.15 KB)
output-user-omp.txt (3.39 KB)
in.uo2 (1.49 KB)