def test_bandstructure_transform_mcl(testdir):
# Test that bandpath() correctly transforms the band path from
# reference (canonical) cell to actual cell provided by user.
def _atoms(cell):
atoms = Atoms(cell=cell, pbc=True)
atoms.calc = FreeElectrons()
return atoms
# MCL with beta > 90, which is a common convention -- but ours is
# alpha < 90. We want the bandpath returned by that cell to yield the
# exact same band structure as our own (alpha < 90) version of the
# same cell.
cell = Cell.new([3., 5., 4., 90., 110., 90.])
lat = cell.get_bravais_lattice()
density = 10.0
cell0 = lat.tocell()
path0 = lat.bandpath(density=density)
print(cell.cellpar().round(3))
print(cell0.cellpar().round(3))
with workdir('files', mkdir=True):
bs = calculate_band_structure(_atoms(cell),
cell.bandpath(density=density))
bs.write('bs.json')
# bs.plot(emin=0, emax=20, filename='fig.bs.svg')
bs0 = calculate_band_structure(_atoms(cell0), path0)
bs0.write('bs0.json')
# bs0.plot(emin=0, emax=20, filename='fig.bs0.svg')
maxerr = np.abs(bs.energies - bs0.energies).max()
assert maxerr < 1e-12, maxerr
def test_bands(siesta_factory):
atoms = bulk('Si')
path = atoms.cell.bandpath('GXWK', density=10)
atoms.calc = siesta_factory.calc(kpts=[2, 2, 2])
bs = calculate_band_structure(atoms, path)
print(bs)
bs.write('bs.json')
def test_lattice_bandstructure(testdir, i, lat, figure):
xid = '{:02d}.{}'.format(i, lat.variant)
path = lat.bandpath(density=10)
path.write('path.{}.json'.format(xid))
atoms = Atoms(cell=lat.tocell(), pbc=True)
atoms.calc = FreeElectrons(nvalence=0, kpts=path.kpts)
bs = calculate_band_structure(atoms, path)
bs.write('bs.{}.json'.format(xid))
ax = figure.gca()
bs.plot(ax=ax, emin=0, emax=20, filename='fig.{}.png'.format(xid))
def free_electron_band_structure(
self, **kwargs) -> 'ase.spectrum.band_structure.BandStructure':
"""Return band structure of free electrons for this bandpath.
Keyword arguments are passed to
:class:`~ase.calculators.test.FreeElectrons`.
This is for mostly testing and visualization."""
from ase import Atoms
from ase.calculators.test import FreeElectrons
from ase.spectrum.band_structure import calculate_band_structure
atoms = Atoms(cell=self.cell, pbc=True)
atoms.calc = FreeElectrons(**kwargs)
bs = calculate_band_structure(atoms, path=self)
return bs
def test_bandstructure_json(testdir):
atoms = bulk('Au')
lat = atoms.cell.get_bravais_lattice()
path = lat.bandpath(npoints=100)
atoms.calc = FreeElectrons()
bs = calculate_band_structure(atoms, path)
bs.write('bs.json')
bs.path.write('path.json')
bs1 = read_json('bs.json')
bs2 = BandStructure.read('bs.json')
path1 = read_json('path.json')
assert type(bs1) == type(bs) # noqa
assert type(bs2) == type(bs) # noqa
assert type(path1) == type(bs.path) # noqa
def test_bandstructure_json():
from ase.build import bulk
from ase.spectrum.band_structure import calculate_band_structure, BandStructure
from ase.io.jsonio import read_json
from ase.calculators.test import FreeElectrons
atoms = bulk('Au')
lat = atoms.cell.get_bravais_lattice()
path = lat.bandpath(npoints=100)
atoms.calc = FreeElectrons()
bs = calculate_band_structure(atoms, path)
bs.write('bs.json')
bs.path.write('path.json')
bs1 = read_json('bs.json')
bs2 = BandStructure.read('bs.json')
path1 = read_json('path.json')
assert type(bs1) == type(bs) # noqa
assert type(bs2) == type(bs) # noqa
assert type(path1) == type(bs.path) # noqa