chore(lmp): add LAMMPS DPA-2 nopbc tests (#4220)

Adding tests to see whether #4167 is resolved. The answer is no. Segfaults are thrown with MPI. <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit - **New Features** - Introduced a new command-line argument `--nopbc` to modify boundary conditions in LAMMPS simulations. - **Tests** - Added a comprehensive suite of unit tests for the DeepMD potential in LAMMPS, covering various configurations and scenarios to ensure accuracy and reliability. <!-- end of auto-generated comment: release notes by coderabbit.ai --> --------- Signed-off-by: Jinzhe Zeng <jinzhe.zeng@rutgers.edu>

Author: njzjz

source/lmp/tests/run_mpi_pair_deepmd.py

@@ -21,6 +21,7 @@
 parser.add_argument("MD_FILE", type=str)
 parser.add_argument("OUTPUT", type=str)
 parser.add_argument("--balance", action="store_true")
+parser.add_argument("--nopbc", action="store_true")
 
 args = parser.parse_args()
 data_file = args.DATAFILE
@@ -38,7 +39,10 @@
  # 6 and 0 atoms
  lammps.processors("1 2 1")
 lammps.units("metal")
-lammps.boundary("p p p")
+if args.nopbc:
+ lammps.boundary("f f f")
+else:
+ lammps.boundary("p p p")
 lammps.atom_style("atomic")
 lammps.neighbor("2.0 bin")
 lammps.neigh_modify("every 10 delay 0 check no")