# Point dipoles in a 3d box with an external potential (ignoring dipolar interactions)

units           lj
atom_style      hybrid sphere dipole
dimension       3
boundary        s s s
region          box block -2 2 -2 2 -2 2

create_box      1 box
create_atoms    1 random 100 12345 NULL

# need both mass settings due to hybrid atom style
mass            1 1.0
set             group all mass 1.0
set             group all diameter 0.1

set             group all dipole/random 98934 0.01
pair_style      none
comm_modify     cutoff 3.0

velocity        all create 0.0 87287 mom yes rot yes

fix             1 all nve/sphere update dipole

###############################################################################################################
## Yukawa potential
#fix            2 all efield/lepton "A*exp(-B*r)/r; r=abs(sqrt(x^2+y^2+z^2)); A = 0.1; B = 5" step 1e-8

## Gradually increasing uniform field 
#variable       E equal ramp(0,1)
#fix            2 all efield/lepton "-v_E*(x+y+z)"

## Linear gradient field
fix             2 all efield/lepton "-1/6*x^3" step 1e-6

fix_modify      2 energy yes

###############################################################################################################

timestep        1e-3

compute         erot all erotate/sphere
variable        etotal equal "ke + c_erot + pe" # thermo etotal doesn't include erot
thermo_style    custom step temp ke c_erot pe v_etotal
thermo          500
thermo_modify   norm no

#dump           1 all custom 500 dump.dipole id x y z diameter mux muy muz fx fy fz tqx tqy tqz

run             10000