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)
  1 by 1 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 = 2.47434 Mbytes
Step Temp E_pair E_mol TotEng Press Volume 
       0          0.1   -3.1333672            0   -3.0921259   -1.1437867    2444.9333 
    1000          0.1   -3.0915465            0   -3.0503052  0.010015559    2444.9333 
    2000          0.1   -3.0826487            0   -3.0414074  -0.42012889    2444.9333 
    3000  0.089819692     -3.07584            0   -3.0387972  -0.25252108    2444.9333 
    4000  0.098489874   -3.0667093            0   -3.0260907  -0.25506538    2444.9333 
    5000   0.11379986   -3.0557087            0   -3.0087762 -0.080871179    2444.9333 
    6000   0.11269179     -3.04532            0   -2.9988445  -0.33381202    2444.9333 
    7000          0.1   -3.0380599            0   -2.9968186  -0.32423949    2444.9333 
    8000          0.1   -3.0346451            0   -2.9934038  -0.38015467    2444.9333 
    9000          0.1   -3.0328231            0   -2.9915818  -0.43229228    2444.9333 
   10000   0.11715901   -3.0339975            0   -2.9856796  -0.32994136    2444.9333 
   11000   0.11489931   -3.0347978            0   -2.9874118  -0.45189608    2444.9333 
   12000   0.10977417   -3.0396002            0    -2.994328  -0.18902632    2444.9333 
   13000          0.1   -3.0460576            0   -3.0048163  -0.30636366    2444.9333 
   14000   0.10650444   -3.0498066            0   -3.0058827  -0.37168966    2444.9333 
   15000   0.11262528    -3.053675            0   -3.0072269  -0.32295729    2444.9333 
   16000   0.10822084   -3.0524308            0   -3.0077991  -0.25034257    2444.9333 
   17000   0.10833465   -3.0487557            0   -3.0040771   -0.4048054    2444.9333 
   18000   0.11599608   -3.0540506            0   -3.0062123  -0.30721348    2444.9333 
   19000   0.11303674   -3.0521905            0   -3.0055727  -0.29399612    2444.9333 
   20000   0.09925739   -3.0483895            0   -3.0074545  -0.34540139    2444.9333 
Loop time of 5.97362 on 1 procs for 20000 steps with 1724 atoms

Pair  time (%) = 4.87956 (81.6851)
Neigh time (%) = 0.32203 (5.39087)
Comm  time (%) = 0.0370991 (0.621049)
Outpt time (%) = 0.000386 (0.00646174)
Other time (%) = 0.734549 (12.2965)

Nlocal:    1724 ave 1724 max 1724 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Nghost:    145 ave 145 max 145 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Neighs:    14387 ave 14387 max 14387 min
Histogram: 1 0 0 0 0 0 0 0 0 0

Total # of neighbors = 14387
Ave neighs/atom = 8.34513
Neighbor list builds = 726
Dangerous builds = 0
