Viewing LAMMPS Results

In the previous section, we saved result file log.lammps to an S3 bucket at destination s3://my-bucket/my-dir/log.lammps.

One method to download the results file to your workstation and view it is to use the AWS CLI to interface with the S3 bucket where your results are stored. If you do not have the AWS CLI installed, please see the AWS CLI installation instructions for more information.

Using the AWS CLI command aws s3 cp, the result file can be downloaded to your workstation. The command below copies the result file at S3 URI s3://my-bucket/my-dir/log.lammps to your working directory.

$ aws s3 cp s3://my-bucket/my-dir/log.lammps .
download: s3://my-bucket/my-dir/log.lammps to ./log.lammps

To view the results, we can simply use the cat command to output the contents of the file to our terminal.

$ cat log.lammps
LAMMPS (29 Sep 2021)
KOKKOS mode is enabled (src/KOKKOS/kokkos.cpp:97)
  will use up to 1 GPU(s) per node
  using 1 OpenMP thread(s) per MPI task
Lattice spacing in x,y,z = 1.6795962 1.6795962 1.6795962
Created orthogonal box = (0.0000000 0.0000000 0.0000000) to (268.73539 134.36770 268.73539)
  1 by 1 by 1 MPI processor grid
Created 8192000 atoms
  using lattice units in orthogonal box = (0.0000000 0.0000000 0.0000000) to (268.73539 134.36770 268.73539)
  create_atoms CPU = 3.047 seconds
Neighbor list info ...
  update every 20 steps, delay 0 steps, check no
  max neighbors/atom: 2000, page size: 100000
  master list distance cutoff = 2.8
  ghost atom cutoff = 2.8
  binsize = 2.8, bins = 96 48 96
  1 neighbor lists, perpetual/occasional/extra = 1 0 0
  (1) pair lj/cut/kk, perpetual
      attributes: full, newton off, kokkos_device
      pair build: full/bin/kk/device
      stencil: full/bin/3d
      bin: kk/device
Setting up Verlet run ...
  Unit style    : lj
  Current step  : 0
  Time step     : 0.005
Per MPI rank memory allocation (min/avg/max) = 1181.0 | 1181.0 | 1181.0 Mbytes
Step Temp E_pair E_mol TotEng Press
       0         1.44   -6.7733681            0   -4.6133683   -5.0196694
     100   0.75927734    -5.761232            0   -4.6223161   0.19102612
Loop time of 1.92832 on 1 procs for 100 steps with 8192000 atoms
Performance: 22402.943 tau/day, 51.859 timesteps/s
72.4% CPU use with 1 MPI tasks x 1 OpenMP threads
MPI task timing breakdown:
Section |  min time  |  avg time  |  max time  |%varavg| %total
---------------------------------------------------------------
Pair    | 0.16802    | 0.16802    | 0.16802    |   0.0 |  8.71
Neigh   | 0.29642    | 0.29642    | 0.29642    |   0.0 | 15.37
Comm    | 0.072074   | 0.072074   | 0.072074   |   0.0 |  3.74
Output  | 0.00063816 | 0.00063816 | 0.00063816 |   0.0 |  0.03
Modify  | 1.3215     | 1.3215     | 1.3215     |   0.0 | 68.53
Other   |            | 0.06967    |            |       |  3.61
Nlocal:    8.19200e+06 ave   8.192e+06 max   8.192e+06 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Nghost:        727553.0 ave      727553 max      727553 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Neighs:         0.00000 ave           0 max           0 min
Histogram: 1 0 0 0 0 0 0 0 0 0
FullNghs:  6.15293e+08 ave 6.15293e+08 max 6.15293e+08 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Total # of neighbors = 6.1529347e+08
Ave neighs/atom = 75.109066
Neighbor list builds = 5
Dangerous builds not checked
Total wall time: 0:00:13

Data in the logs can be used in the various post-processing tools which are compatible with LAMMPS.