LAMMPS (30 Apr 2015)
# 2d friction simulation

dimension	2
boundary	p s p

atom_style	atomic
neighbor	0.3 bin
neigh_modify	delay 5

# create geometry

lattice		hex 0.9
Lattice spacing in x,y,z = 1.1327 1.96189 1.1327
region		box block 0 50 0 22 -0.25 0.25
create_box	4 box
Created orthogonal box = (0 0 -0.283174) to (56.6348 43.1615 0.283174)
  2 by 2 by 1 MPI processor grid

mass		1 1.0
mass		2 1.0
mass		3 1.0
mass		4 1.0

# atom regions

region          lo-fixed block INF INF INF 1.1 INF INF
region          lo-slab block INF INF INF 7 INF INF
region          above-lo block INF INF INF 7 INF INF side out
region          hi-fixed block INF INF 20.9 INF INF INF
region          hi-slab block INF INF 15 INF INF INF
region          below-hi block INF INF 15 INF INF INF side out
region		lo-asperity sphere 32 7 0 8
region		hi-asperity sphere 18 15 0 8
region		lo-half-sphere intersect 2 lo-asperity above-lo
region		hi-half-sphere intersect 2 hi-asperity below-hi

# create 2 surfaces with asperities

create_atoms	1 region lo-slab
Created 750 atoms
create_atoms	1 region hi-slab
Created 750 atoms
create_atoms	2 region lo-half-sphere
Created 112 atoms
create_atoms	3 region hi-half-sphere
Created 112 atoms

# LJ potentials

pair_style	lj/cut 2.5
pair_coeff	* * 1.0 1.0 2.5

# define groups

group	        lo region lo-slab
750 atoms in group lo
group		lo type 2
862 atoms in group lo
group		hi region hi-slab
750 atoms in group hi
group		hi type 3
862 atoms in group hi
group		lo-fixed region lo-fixed
150 atoms in group lo-fixed
group		hi-fixed region hi-fixed
150 atoms in group hi-fixed
group		boundary union lo-fixed hi-fixed
300 atoms in group boundary
group		mobile subtract all boundary
1424 atoms in group mobile

set		group lo-fixed type 4
  150 settings made for type
set		group hi-fixed type 4
  150 settings made for type

# initial velocities

compute         new mobile temp/partial 0 1 0
velocity	mobile create 0.1 482748 temp new
velocity	hi set 1.0 0.0 0.0 sum yes

# fixes

fix		1 all nve
fix		2 boundary setforce 0.0 0.0 0.0
fix		3 mobile temp/rescale 200 0.1 0.1 0.02 1.0
fix_modify	3 temp new
fix             4 all enforce2d

# Run

timestep	0.0025
thermo		1000
thermo_modify	temp new
WARNING: Temperature for thermo pressure is not for group all (../thermo.cpp:445)

#dump		1 all atom 500 dump.friction

#dump		2 all image 500 image.*.jpg type type #		zoom 1.6 adiam 1.5
#dump_modify	2 pad 5

#dump		3 all movie 500 movie.mpg type type #		zoom 1.6 adiam 1.5
#dump_modify	3 pad 5

run		20000
Neighbor list info ...
  1 neighbor list requests
  update every 1 steps, delay 5 steps, check yes
  master list distance cutoff = 2.8
Memory usage per processor = 2.47775 Mbytes
Step Temp E_pair E_mol TotEng Press Volume 
       0          0.1   -3.1333672            0   -3.0921259   -1.1437867    2444.9333 
    1000  0.081958665   -3.0927273            0   -3.0589265 -0.021846131    2444.9333 
    2000  0.082641883   -3.0850764            0   -3.0509938  -0.44960195    2444.9333 
    3000  0.092293442   -3.0748001            0   -3.0367371  -0.25353161    2444.9333 
    4000  0.096012911   -3.0565129            0   -3.0169159 -0.027669541    2444.9333 
    5000          0.1   -3.0465555            0   -3.0053142 -0.099323956    2444.9333 
    6000   0.11642983   -3.0390782            0    -2.991061  -0.21034609    2444.9333 
    7000   0.11597774   -3.0331763            0   -2.9853456  -0.46345898    2444.9333 
    8000   0.11937908   -3.0305561            0   -2.9813227   -0.3077312    2444.9333 
    9000   0.11110633   -3.0274042            0   -2.9815825  -0.52435329    2444.9333 
   10000   0.11593138   -3.0164989            0   -2.9686873  -0.36943466    2444.9333 
   11000   0.11066412   -3.0156369            0   -2.9699976  -0.46759658    2444.9333 
   12000   0.10383247   -3.0199664            0   -2.9771445  -0.27390498    2444.9333 
   13000   0.11288647    -3.027191            0   -2.9806352  -0.38261516    2444.9333 
   14000   0.10587004   -3.0302799            0   -2.9866177  -0.20888958    2444.9333 
   15000   0.11092262   -3.0308702            0   -2.9851243  -0.37310523    2444.9333 
   16000   0.11258624   -3.0421958            0   -2.9957638  -0.27895709    2444.9333 
   17000   0.10980848   -3.0388353            0   -2.9935488  -0.31492687    2444.9333 
   18000   0.11125763   -3.0392991            0    -2.993415  -0.30414022    2444.9333 
   19000   0.11673298   -3.0405242            0    -2.992382  -0.34902574    2444.9333 
   20000   0.11753441   -3.0437232            0   -2.9952505  -0.31244935    2444.9333 
Loop time of 1.90985 on 4 procs for 20000 steps with 1724 atoms

Pair  time (%) = 1.22874 (64.3367)
Neigh time (%) = 0.0816873 (4.27715)
Comm  time (%) = 0.354052 (18.5382)
Outpt time (%) = 0.000435889 (0.0228231)
Other time (%) = 0.244941 (12.8251)

Nlocal:    431 ave 495 max 377 min
Histogram: 1 0 1 0 0 1 0 0 0 1
Nghost:    96 ave 125 max 74 min
Histogram: 1 1 0 0 0 1 0 0 0 1
Neighs:    3597.75 ave 4233 max 3149 min
Histogram: 1 1 0 0 0 1 0 0 0 1

Total # of neighbors = 14391
Ave neighs/atom = 8.34745
Neighbor list builds = 704
Dangerous builds = 0
