### DEFINE SIMULATION BOX GEOMETRY ###
variable latticeparam equal 0.8
lattice sc ${latticeparam}
region box block 0 15 0 15 0 15
create_box 1 box
create_atoms 1 box

### DEFINE PHYSICAL PROPERTIES OF ATOMS ###
mass 1 1.0
pair_style lj/cut/opt 3.0
pair_coeff 1 1 1.0 1.0
neighbor 2.0 bin

### SPECIFY THE REQUIRED THERMODYNAMIC STATE ###
variable T equal 2.0
###variable p equal ...###
variable timestep equal 0.001

### ASSIGN ATOMIC VELOCITIES ###
velocity all create ${T} 12345 dist gaussian rot yes mom yes

### SPECIFY ENSEMBLE ###
timestep ${timestep}
fix nve all nve

### THERMODYNAMIC OUTPUT CONTROL ###
thermo_style custom time etotal temp press
thermo 10

### RECORD TRAJECTORY ###
dump traj all custom 1000 output-1 id x y z

### SPECIFY TIMESTEP ###

### RUN SIMULATION TO MELT CRYSTAL ###
run 10000
unfix nve
reset_timestep 0
 
### BRING SYSTEM TO REQUIRED STATE ###
variable tdamp equal ${timestep}*100
###variable pdamp equal ${timestep}*1000###
fix nvt all nvt temp ${T} ${T} ${tdamp}
run 10000
reset_timestep 0

### MEASURE SYSTEM STATE ###
unfix nvt
fix nve all nve
thermo_style custom etotal temp density atoms vol 
variable dens equal density
variable dens2 equal dens*dens
variable temp equal temp
variable temp2 equal temp*temp
variable etotal equal etotal
variable etotal2 equal etotal*etotal
variable volume equal vol
variable atoms equal atoms
variable atoms2 equal atoms*atoms
fix aves all ave/time 100 1000 100000 v_temp v_temp2 v_etotal v_etotal2 v_volume v_dens
run 100000

variable avetemp equal f_aves[1]
variable avetemp2 equal f_aves[2]
variable errtemp equal sqrt(f_aves[2]-f_aves[1]*f_aves[1])
variable aveetotal equal f_aves[3]
variable aveetotal2 equal f_aves[4]
variable avevolume equal f_aves[5]
variable avedens equal f_aves[6]
variable capv equal ${atoms2}*(${aveetotal2}-(${aveetotal}*${aveetotal}))/${avetemp2}

print "Averages"
print "--------"
print "Number of Atoms: ${atoms}"
print "Temperature: ${avetemp}"
print "Stderr in Temp: ${errtemp}"
print "Cv x kB: ${capv}"
print "Volume: ${avevolume}"
print "Density: ${avedens}"