def test_bravais_2d_cell_pbc():
"""Verify 2D Bravais lattice and band path versus pbc information."""
from ase.cell import Cell
cell = Cell([[1.,0.,0.],
[.1,1.,0.],
[0.,0.,0.]])
lat = cell.get_bravais_lattice()
print(cell.cellpar())
print(lat)
assert lat.name == 'OBL'
cell[2, 2] = 7
lat3d = cell.get_bravais_lattice()
print(lat3d)
assert lat3d.name == 'MCL'
lat2d_pbc = cell.get_bravais_lattice(pbc=[1, 1, 0])
print(lat2d_pbc)
assert lat2d_pbc.name == 'OBL'
path = cell.bandpath()
print(path)
path2d = cell.bandpath(pbc=[1, 1, 0])
print(path2d)
assert path2d.cell.rank == 2
assert path2d.cell.get_bravais_lattice().name == 'OBL'
def kpath(cell, path=None, npoints=None, supercell_matrix=np.eye(3), eps=1e-3):
mycell = Cell(cell)
bpath = mycell.bandpath(path=path, npoints=npoints, eps=eps)
kpts = bpath.kpts
kpts = [np.dot(kpt, supercell_matrix) for kpt in kpts]
x, X, knames = bpath.get_linear_kpoint_axis()
return kpts, x, X, knames
def _path_lengths(path: str, cell: Cell, bands_point_num: int) -> List[int]:
# Construct the metric for reciprocal space (based off Wannier90's "utility_metric" subroutine)
recip_lat = 2 * math.pi * cell.reciprocal().array
recip_metric = recip_lat @ recip_lat.T
# Work out the lengths Wannier90 will assign each path (based off Wannier90's "plot_interpolate_bands" subroutine)
kpath_pts: List[int] = []
kpath_len: List[float] = []
special_points = cell.bandpath().special_points
path_list = path_str_to_list(path, special_points)
for i, (start, end) in enumerate(zip(path_list[:-1], path_list[1:])):
if start == ',':
kpath_pts.append(0)
elif end == ',':
kpath_pts.append(1)
else:
vec = special_points[end] - special_points[start]
kpath_len.append(math.sqrt(vec.T @ recip_metric @ vec))
if i == 0:
kpath_pts.append(bands_point_num)
else:
kpath_pts.append(int(round(bands_point_num * kpath_len[-1] / kpath_len[0])))
return kpath_pts
def construct_kpoint_path(path: str, cell: Cell, bands_point_num: int) -> BandPath:
path_lengths = _path_lengths(path, cell, bands_point_num)
special_points = cell.bandpath().special_points
path_list = path_str_to_list(path, special_points)
kpts = []
for start, end, npoints in zip(path_list[:-1], path_list[1:], path_lengths):
if start == ',':
pass
elif end == ',':
kpts.append(special_points[start].tolist())
else:
bp = bandpath(start + end, cell, npoints + 1)
kpts += bp.kpts[:-1].tolist()
# Don't forget about the final kpoint
kpts.append(bp.kpts[-1].tolist())
if len(kpts) != sum(path_lengths) + 1:
raise AssertionError(
'Did not get the expected number of kpoints; this suggests there is a bug in the code')
return BandPath(cell=cell, kpts=kpts, path=path, special_points=special_points)
"""Verify 2D Bravais lattice and band path versus pbc information.""" from ase.cell import Cell cell = Cell([[1., 0., 0.], [.1, 1., 0.], [0., 0., 0.]]) lat = cell.get_bravais_lattice() print(cell.cellpar()) print(lat) assert lat.name == 'OBL' cell[2, 2] = 7 lat3d = cell.get_bravais_lattice() print(lat3d) assert lat3d.name == 'MCL' lat2d_pbc = cell.get_bravais_lattice(pbc=[1, 1, 0]) print(lat2d_pbc) assert lat2d_pbc.name == 'OBL' path = cell.bandpath() print(path) path2d = cell.bandpath(pbc=[1, 1, 0]) print(path2d) assert path2d.cell.rank == 2 assert path2d.cell.get_bravais_lattice().name == 'OBL'
