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# fmt: off
import numpy as np
import pytest
from numpy.testing import assert_allclose
from ase.build import bulk
from ase.calculators.fd import calculate_numerical_stress
from ase.filters import FrechetCellFilter
from ase.optimize import BFGS
@pytest.mark.calculator_lite()
@pytest.mark.calculator('lammpsrun')
def test_Pt_stress_cellopt(factory):
params = {}
params['pair_style'] = 'eam'
params['pair_coeff'] = ['1 1 Pt_u3.eam']
files = [f'{factory.factory.potentials_path}/Pt_u3.eam']
# XXX Should it accept Path objects? Yes definitely for files.
with factory.calc(specorder=['Pt'], files=files, **params) as calc:
rng = np.random.RandomState(17)
atoms = bulk('Pt') * (2, 2, 2)
atoms.rattle(stdev=0.1)
atoms.cell += 2 * rng.random((3, 3))
atoms.calc = calc
assert_allclose(atoms.get_stress(),
calculate_numerical_stress(atoms),
atol=1e-4, rtol=1e-4)
with BFGS(FrechetCellFilter(atoms)) as opt:
for i, _ in enumerate(opt.irun(fmax=0.001)):
pass
cell1_ref = np.array([
[0.178351, 3.885347, 3.942046],
[4.19978, 0.591071, 5.062568],
[4.449044, 3.264038, 0.471548],
])
assert_allclose(np.asarray(atoms.cell), cell1_ref,
atol=3e-4, rtol=3e-4)
assert_allclose(atoms.get_stress(),
calculate_numerical_stress(atoms),
atol=1e-4, rtol=1e-4)
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