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# fmt: off
import itertools
import numpy as np
import pytest
from ase.cell import Cell
def test_niggli_0d():
rcell, op = Cell.new().niggli_reduce()
assert rcell.rank == 0
assert (op == np.identity(3, dtype=int)).all()
def test_niggli_1d():
cell = Cell.new()
vector = [1, 2, 3]
cell[1] = vector
rcell, op = cell.niggli_reduce()
assert rcell.lengths() == pytest.approx([np.linalg.norm(vector), 0, 0])
assert Cell(op.T @ cell).cellpar() == pytest.approx(rcell.cellpar())
def test_niggli_2d():
cell = Cell.new()
cell[0] = [3, 4, 5]
cell[2] = [5, 6, 7]
rcell, op = cell.niggli_reduce()
assert rcell.rank == 2
assert rcell.lengths()[2] == 0
assert Cell(op.T @ cell).cellpar() == pytest.approx(rcell.cellpar())
@pytest.mark.parametrize('npbc', [0, 1, 2, 3])
@pytest.mark.parametrize('perm', itertools.permutations(range(3)))
def test_niggli_atoms_ndim(npbc, perm):
from ase.build import fcc111, niggli_reduce
from ase.calculators.emt import EMT
from ase.geometry.geometry import permute_axes
perm = np.array(perm)
atoms = fcc111('Au', (2, 3, 1), vacuum=2.0)
atoms.pbc = False
atoms.pbc[:npbc] = True
atoms.cell[2] = [0, 0, 1]
if npbc == 1:
atoms.cell[1] = [0, 0, 0]
atoms.rattle(stdev=0.1)
atoms = permute_axes(atoms, perm)
atoms.calc = EMT()
e1 = atoms.get_potential_energy()
niggli_reduce(atoms)
e2 = atoms.get_potential_energy()
assert e2 == pytest.approx(e1, abs=1e-10)
def test_no_nonorthogonal_niggli():
from ase.build import bulk, niggli_reduce
atoms = bulk('Au')
atoms.pbc[1] = False
with pytest.raises(ValueError, match='Non-orthogonal'):
niggli_reduce(atoms)
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