LAMMPS (10 Feb 2021)
# 3d Lennard-Jones melt

variable     x index 1
variable     y index 1
variable     z index 1

variable     xx equal 20*$x
variable     xx equal 20*1
variable     yy equal 20*$y
variable     yy equal 20*1
variable     zz equal 20*$z
variable     zz equal 20*1

units        real

lattice      fcc 4.4300
Lattice spacing in x,y,z = 4.4300000 4.4300000 4.4300000
region       box block 0 ${xx} 0 ${yy} 0 ${zz}
region       box block 0 20 0 ${yy} 0 ${zz}
region       box block 0 20 0 20 0 ${zz}
region       box block 0 20 0 20 0 20
create_box   1 box
Created orthogonal box = (0.0000000 0.0000000 0.0000000) to (88.600000 88.600000 88.600000)
  1 by 1 by 1 MPI processor grid
create_atoms 1 box
Created 32000 atoms
  create_atoms CPU = 0.002 seconds

pair_style   lj/cut 8.1500
pair_coeff   1 1 0.0104 3.4000

#pair_style  kim LennardJones_Ar
#pair_coeff  * * Ar

mass         1 39.95
velocity     all create 200.0 232345 loop geom

neighbor     0.3 bin
neigh_modify delay 0 every 1 check yes

fix          1 all nve
#fix         1 all npt temp 1.0 1.0 1.0 iso 1.0 1.0 3.0

run          100
Neighbor list info ...
  update every 1 steps, delay 0 steps, check yes
  max neighbors/atom: 2000, page size: 100000
  master list distance cutoff = 8.45
  ghost atom cutoff = 8.45
  binsize = 4.225, bins = 21 21 21
  1 neighbor lists, perpetual/occasional/extra = 1 0 0
  (1) pair lj/cut, perpetual
      attributes: half, newton on
      pair build: half/bin/atomonly/newton
      stencil: half/bin/3d/newton
      bin: standard
Per MPI rank memory allocation (min/avg/max) = 19.23 | 19.23 | 19.23 Mbytes
Step Temp E_pair E_mol TotEng Press 
       0          200    6290.8194            0    25367.408    6750.7421 
     100    98.747096    15900.676            0    25319.465    10184.453 
Loop time of 1.87123 on 1 procs for 100 steps with 32000 atoms

Performance: 4.617 ns/day, 5.198 hours/ns, 53.441 timesteps/s
99.9% CPU use with 1 MPI tasks x no OpenMP threads

MPI task timing breakdown:
Section |  min time  |  avg time  |  max time  |%varavg| %total
---------------------------------------------------------------
Pair    | 1.686      | 1.686      | 1.686      |   0.0 | 90.10
Neigh   | 0.14211    | 0.14211    | 0.14211    |   0.0 |  7.59
Comm    | 0.01013    | 0.01013    | 0.01013    |   0.0 |  0.54
Output  | 6.3e-05    | 6.3e-05    | 6.3e-05    |   0.0 |  0.00
Modify  | 0.022686   | 0.022686   | 0.022686   |   0.0 |  1.21
Other   |            | 0.0102     |            |       |  0.55

Nlocal:        32000.0 ave       32000 max       32000 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Nghost:        19911.0 ave       19911 max       19911 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Neighs:    1.96027e+06 ave 1.96027e+06 max 1.96027e+06 min
Histogram: 1 0 0 0 0 0 0 0 0 0

Total # of neighbors = 1960266
Ave neighs/atom = 61.258313
Neighbor list builds = 3
Dangerous builds = 0
Total wall time: 0:00:01