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def test_monoclinic():
"""Test band structure from different variations of hexagonal cells."""
import numpy as np
from ase import Atoms
from ase.calculators.test import FreeElectrons
from ase.geometry import (crystal_structure_from_cell, cell_to_cellpar,
cellpar_to_cell)
from ase.dft.kpoints import get_special_points
mc1 = [[1, 0, 0], [0, 1, 0], [0, 0.2, 1]]
par = cell_to_cellpar(mc1)
mc2 = cellpar_to_cell(par)
mc3 = [[1, 0, 0], [0, 1, 0], [-0.2, 0, 1]]
mc4 = [[1, 0, 0], [-0.2, 1, 0], [0, 0, 1]]
path = 'GYHCEM1AXH1'
firsttime = True
for cell in [mc1, mc2, mc3, mc4]:
a = Atoms(cell=cell, pbc=True)
a.cell *= 3
a.calc = FreeElectrons(nvalence=1, kpts={'path': path})
cs = crystal_structure_from_cell(a.cell)
assert cs == 'monoclinic'
r = a.cell.reciprocal()
k = get_special_points(a.cell)['H']
print(np.dot(k, r))
a.get_potential_energy()
bs = a.calc.band_structure()
coords, labelcoords, labels = bs.get_labels()
assert ''.join(labels) == path
e_skn = bs.energies
# bs.plot()
if firsttime:
coords1 = coords
labelcoords1 = labelcoords
e_skn1 = e_skn
firsttime = False
else:
for d in [coords - coords1,
labelcoords - labelcoords1,
e_skn - e_skn1]:
print(abs(d).max())
assert abs(d).max() < 1e-13, d
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