def get_band_structure(self,
band_paths: list,
labels: list = None,
npoints: int = 51,
with_eigenvectors: bool = False,
use_reciprocal_lattice: bool = True):
"""
Get BandStructure class object.
Args:
band_paths (list): Band paths.
labels (list): Band labels.
npoints (int): The number of sampling points.
with_eigenvectors (bool): If True, calculte eigenvectors.
"""
if use_reciprocal_lattice:
rec_lattice = self._reciprocal_lattice
else:
rec_lattice = None
qpoints, connections = get_band_qpoints_and_path_connections(
band_paths=band_paths, npoints=npoints, rec_lattice=rec_lattice)
band_structure = BandStructure(
paths=qpoints,
dynamical_matrix=self._phonon.get_dynamical_matrix(),
with_eigenvectors=with_eigenvectors,
is_band_connection=False,
group_velocity=None,
path_connections=connections,
labels=labels,
is_legacy_plot=False)
return band_structure
def set_band_structure(self,
bands,
is_eigenvectors=False,
is_band_connection=False):
self._set_dynamical_matrix()
self._band_structure = BandStructure(
bands,
self._dynamical_matrix,
is_eigenvectors=is_eigenvectors,
is_band_connection=is_band_connection,
group_velocity=self._group_velocity,
factor=self._factor)
def get_bandstructure(self):
phonopy_obj = self.phonopy_obj
frequency_unit_factor = VaspToTHz
is_eigenvectors = False
unit_cell = phonopy_obj.unitcell.get_cell()
sym_tol = phonopy_obj.symmetry.tolerance
if self.band_conf is not None:
parameters = read_kpath(self.band_conf)
else:
parameters = generate_kpath_ase(unit_cell, sym_tol)
if not parameters:
return None, None, None
# Distances calculated in phonopy.band_structure.BandStructure object
# are based on absolute positions of q-points in reciprocal space
# as calculated by using the cell which is handed over during instantiation.
# Fooling that object by handing over a "unit cell" diag(1,1,1) instead clashes
# with calculation of non-analytical terms.
# Hence generate appropriate distances and special k-points list based on fractional
# coordinates in reciprocal space (to keep backwards compatibility with previous
# FHI-aims phonon implementation).
bands = []
bands_distances = []
distance = 0.0
bands_special_points = [distance]
bands_labels = []
label = parameters[0]["startname"]
for b in parameters:
kstart = np.array(b["kstart"])
kend = np.array(b["kend"])
npoints = b["npoints"]
dk = (kend - kstart) / (npoints - 1)
bands.append([(kstart + dk * n) for n in range(npoints)])
dk_length = np.linalg.norm(dk)
for n in range(npoints):
bands_distances.append(distance + dk_length * n)
distance += dk_length * (npoints - 1)
bands_special_points.append(distance)
label = [b["startname"], b["endname"]]
bands_labels.append(label)
bs_obj = BandStructure(bands,
phonopy_obj.dynamical_matrix,
with_eigenvectors=is_eigenvectors,
factor=frequency_unit_factor)
freqs = bs_obj.get_frequencies()
return np.array(freqs), np.array(bands), np.array(bands_labels)
def set_band_structure(self,
bands,
is_eigenvectors=False,
is_band_connection=False):
if self._dynamical_matrix is None:
print("Warning: Dynamical matrix has not yet built.")
self._band_structure = None
return False
self._band_structure = BandStructure(
bands,
self._dynamical_matrix,
is_eigenvectors=is_eigenvectors,
is_band_connection=is_band_connection,
group_velocity=self._group_velocity,
factor=self._factor)
return True
band = []
for i in range(51):
band.append(q_start + (q_end - q_start) / 50 * i)
bands.append(band)
dir_labels = [r'$\Gamma$', '$X$', '$W$', '$X$', '$K$', r'$\Gamma$', '$L$']
# plot the band structure
clf()
phonon.set_band_structure(bands)
phonon.plot_band_structure(dir_labels)
ylim(0, 20.)
# save results to file band.yaml
bs = BandStructure(bands,
phonon.dynamical_matrix,
phonon.primitive,
factor=VaspToTHz)
if write_yaml:
bs.write_yaml()
# add vertical lines to plot
for p in bs.special_point:
axvline(p, color='k')
# Example showing how to load previously saved results
if read_yaml:
special_points, distances, frequencies = band_plot_from_file(
gca(), 'band.yaml')
# set x axis labels
