def test_convert_to_ieee(self):
for entry in self.ieee_data:
xtal = entry["xtal"]
struct = entry["structure"]
orig = Tensor(entry["original_tensor"])
ieee = Tensor(entry["ieee_tensor"])
diff = np.max(abs(ieee - orig.convert_to_ieee(struct)))
err_msg = f"{xtal} IEEE conversion failed with max diff {diff}. Numpy version: {np.__version__}"
converted = orig.convert_to_ieee(struct, refine_rotation=False)
self.assertArrayAlmostEqual(ieee,
converted,
err_msg=err_msg,
decimal=3)
converted_refined = orig.convert_to_ieee(struct,
refine_rotation=True)
err_msg = "{} IEEE conversion with refinement failed with max diff {}. Numpy version: {}".format(
xtal, diff, np.__version__)
self.assertArrayAlmostEqual(ieee,
converted_refined,
err_msg=err_msg,
decimal=2)
def calc(self, item):
"""
Process the tasks and materials into a dielectrics collection
Args:
item dict: a dict of material_id, structure, and tasks
Returns:
dict: a dieletrics dictionary
"""
def poly(matrix):
diags = np.diagonal(matrix)
return np.prod(diags) / np.sum(
np.prod(comb) for comb in combinations(diags, 2))
if item["bandstructure"]["band_gap"] > 0:
structure = Structure.from_dict(
item.get("dielectric", {}).get("structure", None))
ionic = Tensor(
item["dielectric"]["ionic"]).convert_to_ieee(structure)
static = Tensor(
item["dielectric"]["static"]).convert_to_ieee(structure)
total = ionic + static
d = {
"dielectric": {
"total": total,
"ionic": ionic,
"static": static,
"e_total": np.average(np.diagonal(total)),
"e_ionic": np.average(np.diagonal(ionic)),
"e_static": np.average(np.diagonal(static)),
"n": np.sqrt(np.average(np.diagonal(static))),
}
}
sga = SpacegroupAnalyzer(structure)
# Update piezo if non_centrosymmetric
if item.get("piezo", False) and not sga.is_laue():
static = PiezoTensor.from_voigt(
np.array(item["piezo"]["static"]))
ionic = PiezoTensor.from_voigt(np.array(
item["piezo"]["ionic"]))
total = ionic + static
# Symmeterize Convert to IEEE orientation
total = total.convert_to_ieee(structure)
ionic = ionic.convert_to_ieee(structure)
static = static.convert_to_ieee(structure)
directions, charges, strains = np.linalg.svd(
total.voigt, full_matrices=False)
max_index = np.argmax(np.abs(charges))
max_direction = directions[max_index]
# Allow a max miller index of 10
min_val = np.abs(max_direction)
min_val = min_val[min_val > (np.max(min_val) /
self.max_miller)]
min_val = np.min(min_val)
d["piezo"] = {
"total": total.zeroed().voigt,
"ionic": ionic.zeroed().voigt,
"static": static.zeroed().voigt,
"e_ij_max": charges[max_index],
"max_direction": np.round(max_direction / min_val),
"strain_for_max": strains[max_index],
}
else:
d = {
"dielectric": {},
"_warnings": [
"Dielectric calculated for likely metal. Values are unlikely to be converged"
],
}
if item.get("piezo", False):
d.update({
"piezo": {},
"_warnings": [
"Piezoelectric calculated for likely metal. Values are unlikely to be converged"
],
})
return d