# -------------------------------------------------------------
# Bulk configuration
# -------------------------------------------------------------

# Set up lattice
vector_a = [5.4306, 0.0, 0.0]*Angstrom
vector_b = [0.0, 5.4306, 0.0]*Angstrom
vector_c = [0.0, 0.0, 5.4306]*Angstrom
lattice = UnitCell(vector_a, vector_b, vector_c)

# Define elements
elements = [Silicon, Silicon, Silicon, Silicon, Silicon, Silicon, Silicon,
            Silicon]

# Define coordinates
fractional_coordinates = [[0.0 ,  0.0 ,  0.0 ],
                          [0.25,  0.25,  0.25],
                          [0.5 ,  0.5 ,  0.0 ],
                          [0.75,  0.75,  0.25],
                          [0.5 ,  0.0 ,  0.5 ],
                          [0.75,  0.25,  0.75],
                          [0.0 ,  0.5 ,  0.5 ],
                          [0.25,  0.75,  0.75]]

# Set up configuration
bulk_configuration = BulkConfiguration(
    bravais_lattice=lattice,
    elements=elements,
    fractional_coordinates=fractional_coordinates
    )

# -------------------------------------------------------------
# Calculator
# -------------------------------------------------------------

potentialSet = StillingerWeber_Si_1985()
calculator = TremoloXCalculator(parameters=potentialSet)

bulk_configuration.setCalculator(calculator)
bulk_configuration.update()

# -------------------------------------------------------------
# Time-Stamped Force-Bias Monte Carlo
# -------------------------------------------------------------

method = ForceBiasMonteCarloNPTBerendsen(
    temperature=500*Kelvin,
    max_atom_displacement=0.1*Angstrom,
    pressure=1*bar,
    barostat_factor=500,
    compressibility=0.0001*bar**-1,
)

mc_trajectory = TimeStampedForceBiasMonteCarlo(
    bulk_configuration,
    constraints=[],
    trajectory_filename='tfmc_trajectory.hdf5',
    steps=500,
    log_interval=50,
    method=method
)

bulk_configuration = mc_trajectory.lastImage()