### DEFINE SIMULATION BOX GEOMETRY ###
variable density equal 0.2
variable temperature equal 2.0
variable timestep equal 0.001

lattice sc ${density}
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

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

### BRING SYSTEM TO REQUIRED STATE ###
variable tdamp equal ${timestep}*100
fix nvt all nvt temp ${temperature} ${temperature} ${tdamp} 
run 10000
reset_timestep 0

### 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 nvt
reset_timestep 0

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

### MEASURE SYSTEM STATE ###
thermo_style custom step etotal temp density
variable dens equal density
variable dens2 equal density*density
variable temp equal temp
variable temp2 equal temp*temp
variable etotal equal etotal
variable etotal2 equal etotal*etotal
fix aves all ave/time 100 1000 100000 v_dens v_temp v_etotal v_dens2 v_temp2 v_etotal2
run 100000

variable avedens equal f_aves[1]
variable avetemp equal f_aves[2]
variable aveetotal equal f_aves[3]
variable aveetotal2 equal f_aves[6]
variable errdens equal sqrt(f_aves[4]-f_aves[1]*f_aves[1])
variable errtemp equal sqrt(f_aves[5]-f_aves[2]*f_aves[2])
variable erretotal equal sqrt(f_aves[6]-f_aves[3]*f_aves[3])
variable heatcap equal ((3375*3375)*(f_aves[6]-(f_aves[3]*f_aves[3])))/(f_aves[2]*f_aves[2])


print "Averages"
print "--------"
print "Density: ${avedens}"
print "Stderr: ${errdens}"
print "Temperature: ${avetemp}"
print "Stderr: ${errtemp}"
print "Energy: ${aveetotal}"
print "Stderr: ${erretotal}"
print "HeatCap: ${heatcap}"