7. Troubleshooting

7.1. Check LAMMPS python API

If there is some problem with LAMMPS installation this is a simple script that can help you to find it out. Run this script inside one of the example folders (where in.lammps file is placed)

from lammps import lammps

lmp1 = lammps()
lmp1.file("in.lammps")
lmp1.close()

if everything works as expected you should get an output like this

LAMMPS (15 May 2019)
OMP_NUM_THREADS environment is not set. Defaulting to 1 thread. (src/comm.cpp:88)
  using 1 OpenMP thread(s) per MPI task
Lattice spacing in x,y,z = 4.785 2.76262 5.189
Created triclinic box = (0 0 0) to (3.19 2.76262 5.189) with tilt (-1.595 0 0)
WARNING: Triclinic box skew is large (src/domain.cpp:194)
  1 by 1 by 1 MPI processor grid
Created 4 atoms
  create_atoms CPU = 0.00049852 secs
Reading potential file GaN.tersoff with DATE: 2007-10-22
Total wall time: 0:00:00

otherwise there may be some trouble with LAMMPS python interface. Check LAMMPS manual for further information.

7.2. Check LAMMPS calculations log

By default LAMMPS logs are deactivated and not shown during the calculation. If issues appear it may be useful to check LAMMPS force calculations logs. This is done by using -logshow flag. Ex:

$ phonolammps in.lammps --dim 2 2 2 --logshow