Inquiry about Lammps Simulation Results of Tutorial-01

[vikramroybarc]

Dear Mark,

I am currently learning to utilize Lammps software for atomistic simulations to extract material parameters necessary for continuum modeling of materials and alloys, such as employing crystal plasticity. I am writing to seek your assistance regarding some doubts I have encountered while interpreting the simulation results from the Lammps log file. Your Tutorial - 01 has been immensely helpful in understanding the intricacies of molecular dynamics simulations.

However, I have come across a few sections in the log file that I am having trouble comprehending. I was hoping you could kindly shed some light on them:

1. The following portion of the output appears in the log file, and I am unsure about its significance:

Nlocal:              2 ave           2 max           2 min
Histogram: 4 0 0 0 0 0 0 0 0 0
Nghost:            459 ave         459 max         459 min
Histogram: 4 0 0 0 0 0 0 0 0 0
Neighs:            140 ave         151 max         129 min
Histogram: 1 0 1 0 0 0 0 1 0 1

2. In Tutorial-01, a total of 8 atoms were modeled as indicated in the Lammps log file:

replicate 1 1 1
Replicating atoms ...
  orthogonal box = (0 0 0) to (5.6568542 5.6568542 4)
  2 by 2 by 1 MPI processor grid
  8 atoms
  replicate CPU = 0.004 seconds

However, later in the output file, it shows that the number of neighbors is equal to 560:

Total # of neighbors = 560
Ave neighs/atom = 70
Neighbor list builds = 0
Dangerous builds = 0

I am puzzled as to how the number of neighbors can be 560 for only 8 atoms in the simulation.

To facilitate your assistance, I have attached the input file and log file to this message.

Thank you for taking the time to review my inquiries. Your guidance will be immensely valuable to me in gaining a better understanding of these simulation results.

Best Regards,
Vikram Roy
Country: India
log.lammps.txt
calc_fcc.in.txt