# -*- coding: utf-8 -*-
setVerbosity(MinimalLog)

# -------------------------------------------------------------
# Bulk Configuration
# -------------------------------------------------------------

# Set up lattice
lattice = FaceCenteredCubic(5.762862000000001*Angstrom)

# Define elements
elements = [Germanium, Germanium]

# Define coordinates
fractional_coordinates = [[ 0.375,  0.375,  0.375],
                          [ 0.625,  0.625,  0.625]]

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

# -------------------------------------------------------------
# Calculator
# -------------------------------------------------------------
exchange_correlation = HybridGGA.HSE06

k_point_sampling = KpointDensity(
    density_a=4.0*Angstrom,
    )
numerical_accuracy_parameters = NumericalAccuracyParameters(
    density_mesh_cutoff=120.0*Hartree,
    k_point_sampling=k_point_sampling,
    )

calculator = LCAOCalculator(
    exchange_correlation=exchange_correlation,
    numerical_accuracy_parameters=numerical_accuracy_parameters,
    )

bulk_configuration.setCalculator(calculator)
nlprint(bulk_configuration)
bulk_configuration.update()
nlsave('PBE.hdf5', bulk_configuration)

# -------------------------------------------------------------
# Optimize Geometry
# -------------------------------------------------------------
constraints = [SpaceGroupConstraint()]

bulk_configuration = OptimizeGeometry(
    bulk_configuration,
    max_forces=0.05*eV/Ang,
    max_stress=0.1*GPa,
    max_steps=200,
    max_step_length=0.2*Ang,
    constraints=constraints,
    trajectory_filename='PBE_trajectory.hdf5',
    trajectory_interval=1,
    restart_strategy=RestartFromTrajectory(),
    optimizer_method=LBFGS(),
    enable_optimization_stop_file=True,
)
nlsave('PBE.hdf5', bulk_configuration)
nlprint(bulk_configuration)

# -------------------------------------------------------------
# Total Energy
# -------------------------------------------------------------
total_energy = TotalEnergy(bulk_configuration)
nlsave('PBE.hdf5', total_energy)
nlprint(total_energy)

# -------------------------------------------------------------
# Bandstructure
# -------------------------------------------------------------
bandstructure = Bandstructure(
    configuration=bulk_configuration,
    route=['G', 'X', 'W', 'L', 'G', 'K', 'X', 'U', 'W', 'K', 'L'],
    points_per_segment=50,
    bands_above_fermi_level=All,
    method=Full,
    )
nlsave('PBE.hdf5', bandstructure)

# -------------------------------------------------------------
# Projected Density Of States
# -------------------------------------------------------------
kpoint_grid = KpointDensity(
    density_a=7.0*Angstrom,
    )

projected_density_of_states = ProjectedDensityOfStates(
    configuration=bulk_configuration,
    kpoints=kpoint_grid,
    projections=ProjectOnSites,
    energies=numpy.linspace(-8, 8, 601)*eV,
    energy_zero_parameter=FermiLevel,
    bands_above_fermi_level=All,
    spectrum_method=TetrahedronMethod,
)
nlsave('PBE.hdf5', projected_density_of_states)