# Set up lattice
lattice = FaceCenteredCubic(5.4306 * Angstrom)

# Define elements
elements = [Silicon, Silicon]

# Define coordinates
fractional_coordinates = [[ 0.  ,  0.  ,  0.  ],
                          [ 0.25,  0.25,  0.25]]

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

# k-point sampling
k_point_sampling = MonkhorstPackGrid(
    na=3,
    nb=3,
    nc=3,
    )

numerical_accuracy_parameters = NumericalAccuracyParameters(
    k_point_sampling=k_point_sampling,
    )

# LCAO calculator
calculator = LCAOCalculator(
    numerical_accuracy_parameters=numerical_accuracy_parameters,
    )

bulk_configuration.setCalculator(calculator)
bulk_configuration.update()

# Calculate and save the eigenvalues
eigenvalues = Eigenvalues(bulk_configuration)
nlprint(eigenvalues)
nlsave('eigenvalues.hdf5', eigenvalues)