def test_scaled_cell_and_fractional_coordinates(structures):
"""Make sure these two different calculations arrive at the same result"""
for structure in structures:
scale = scaled_cell(structure.lattice_vectors)
scale = numpy.asarray(scale)
cartesian_positions = numpy.asarray(structure.cartesian_site_positions)
scaled_fractional_positions = (scale.T @ cartesian_positions.T).T
for i in range(3):
scaled_fractional_positions[:, i] %= 1.0
scaled_fractional_positions[:, i] %= 1.0
scaled_fractional_positions = [
tuple(position) for position in scaled_fractional_positions
]
calculated_fractional_positions = fractional_coordinates(
cell=structure.lattice_vectors,
cartesian_positions=structure.cartesian_site_positions,
)
for scaled_position, calculated_position in zip(
scaled_fractional_positions, calculated_fractional_positions):
assert scaled_position == pytest.approx(calculated_position)
def get_pdbx_mmcif( # pylint: disable=too-many-locals
optimade_structure: OptimadeStructure, ) -> str: # pragma: no cover
""" Write Protein Data Bank (PDB) structure in the PDBx/mmCIF format from OPTIMADE structure
Inspired by `ase.io.proteindatabank:write_proteindatabank()` in the ASE package,
as well as `ase.io.cif:write_cif()`.
:param optimade_structure: OPTIMADE structure
:return: str
"""
if globals().get("np", None) is None:
warn(NUMPY_NOT_FOUND)
return None
cif = """#
# Created from an OPTIMADE structure.
#
# See https://www.optimade.org and/or
# https://github.com/Materials-Consortia/OPTIMADE for more information.
#
# CIF 2.0 format, specifically mmCIF (PDBx).
# See http://mmcif.wwpdb.org for more information.
#
"""
entry_id = f"{optimade_structure.type}{optimade_structure.id}"
cif += f"data_{entry_id}\n_entry.id {entry_id}\n#\n"
attributes = optimade_structure.attributes
# Do this only if there's three non-zero lattice vectors
if all(attributes.dimension_types):
a_vector, b_vector, c_vector, alpha, beta, gamma = cell_to_cellpar(
attributes.lattice_vectors)
cif += (f"_cell.entry_id {entry_id}\n"
f"_cell.length_a {a_vector:g}\n"
f"_cell.length_b {b_vector:g}\n"
f"_cell.length_c {c_vector:g}\n"
f"_cell.angle_alpha {alpha:g}\n"
f"_cell.angle_beta {beta:g}\n"
f"_cell.angle_gamma {gamma:g}\n"
"_cell.Z_PDB 1\n#\n")
cif += (f"_symmetry.entry_id {entry_id}\n"
"_symmetry.space_group_name_H-M 'P 1'\n"
"_symmetry.Int_Tables_number 1\n#\n")
# Since some structure viewers are having issues with cartesian coordinates,
# we calculate the fractional coordinates if this is a 3D structure and we have all the necessary information.
if not hasattr(attributes, "fractional_site_positions"):
sites, _ = pad_positions(attributes.cartesian_site_positions)
attributes.fractional_site_positions = fractional_coordinates(
cell=attributes.lattice_vectors, cartesian_positions=sites)
# TODO: The following lines are perhaps needed to create a "valid" PDBx/mmCIF file.
# However, at the same time, the information here is "default" and will for all structures "at this moment in time"
# be the same. I.e., no information is gained by adding this now.
# If it is found that they indeed are needed to create a "valid" PDBx/mmCIF file, they should be included in the output.
# cif += (
# "loop_\n"
# "_struct_asym.id\n"
# "_struct_asym.entity_id\n"
# "A 1\n#\n" # At this point, not using this feature.
# )
# cif += (
# "loop_\n"
# "_chem_comp.id\n"
# "X\n#\n" # At this point, not using this feature.
# )
# cif += (
# "loop_\n"
# "_entity.id\n"
# "1\n#\n" # At this point, not using this feature.
# )
# NOTE: This is otherwise a bit ahead of its time, since this OPTIMADE property is part of an open PR.
# See https://github.com/Materials-Consortia/OPTIMADE/pull/206
coord_type = ("fract" if hasattr(attributes, "fractional_site_positions")
else "Cartn")
cif += (
"loop_\n"
"_atom_site.group_PDB\n" # Always "ATOM"
"_atom_site.id\n" # number (1-counting)
"_atom_site.type_symbol\n" # species.chemical_symbols
"_atom_site.label_atom_id\n" # species.checmical_symbols symbol + number
# For these next keys, see the comment above.
# "_atom_site.label_asym_id\n" # Will be set to "A" _struct_asym.id above
# "_atom_site.label_comp_id\n" # Will be set to "X" _chem_comp.id above
# "_atom_site.label_entity_id\n" # Will be set to "1" _entity.id above
# "_atom_site.label_seq_id\n"
"_atom_site.occupancy\n" # species.concentration
f"_atom_site.{coord_type}_x\n" # cartesian_site_positions
f"_atom_site.{coord_type}_y\n" # cartesian_site_positions
f"_atom_site.{coord_type}_z\n" # cartesian_site_positions
"_atom_site.thermal_displace_type\n" # Set to 'Biso'
"_atom_site.B_iso_or_equiv\n" # Set to 1.0:f
)
if coord_type == "fract":
sites, _ = pad_positions(attributes.fractional_site_positions)
else:
sites, _ = pad_positions(attributes.cartesian_site_positions)
species: Dict[str, OptimadeStructureSpecies] = {
species.name: species
for species in attributes.species
}
for site_number in range(attributes.nsites):
species_name = attributes.species_at_sites[site_number]
site = sites[site_number]
current_species = species[species_name]
for index, symbol in enumerate(current_species.chemical_symbols):
if symbol == "vacancy":
continue
label = f"{species_name.upper()}{site_number + 1}"
if len(current_species.chemical_symbols) > 1:
if ("vacancy" in current_species.chemical_symbols
and len(current_species.chemical_symbols) == 2):
pass
else:
label = f"{symbol.upper()}{index + 1}"
cif += (
f"ATOM {site_number + 1:5d} {symbol} {label:8} "
f"{current_species.concentration[index]:6.4f} {site[0]:8.5f} "
f"{site[1]:8.5f} {site[2]:8.5f} {'Biso':4} {'1.000':6}\n")
return cif
def get_cif( # pylint: disable=too-many-locals,too-many-branches
optimade_structure: OptimadeStructure,
) -> str:
""" Get CIF file as string from OPTIMADE structure
Based on `ase.io.cif:write_cif()`.
:param optimade_structure: OPTIMADE structure
:param formatting: What formatting to use for the CIF file data keys.
Can be either "mp" or "default".
:param encoding: Encoding used for the string. CIF files use "latin-1" as standard.
If encoding is "str", a Python str object will be returned.
:return: str
"""
# NumPy is needed for calculations
if globals().get("np", None) is None:
warn(NUMPY_NOT_FOUND)
return None
cif = """#
# Created from an OPTIMADE structure.
#
# See https://www.optimade.org and/or
# https://github.com/Materials-Consortia/OPTIMADE for more information.
#
"""
cif += f"data_{optimade_structure.id}\n\n"
attributes = optimade_structure.attributes
# Do this only if there's three non-zero lattice vectors
# NOTE: This also negates handling of lattice_vectors with null/None values
if all(attributes.dimension_types):
a_vector, b_vector, c_vector, alpha, beta, gamma = cell_to_cellpar(
attributes.lattice_vectors
)
cif += (
f"_cell_length_a {a_vector:g}\n"
f"_cell_length_b {b_vector:g}\n"
f"_cell_length_c {c_vector:g}\n"
f"_cell_angle_alpha {alpha:g}\n"
f"_cell_angle_beta {beta:g}\n"
f"_cell_angle_gamma {gamma:g}\n\n"
)
cif += (
"_symmetry_space_group_name_H-M 'P 1'\n"
"_symmetry_int_tables_number 1\n\n"
"loop_\n"
" _symmetry_equiv_pos_as_xyz\n"
" 'x, y, z'\n\n"
)
# Since some structure viewers are having issues with cartesian coordinates,
# we calculate the fractional coordinates if this is a 3D structure and we have all the necessary information.
if not hasattr(attributes, "fractional_site_positions"):
sites, _ = pad_positions(attributes.cartesian_site_positions)
attributes.fractional_site_positions = fractional_coordinates(
cell=attributes.lattice_vectors, cartesian_positions=sites
)
# NOTE: This is otherwise a bit ahead of its time, since this OPTIMADE property is part of an open PR.
# See https://github.com/Materials-Consortia/OPTIMADE/pull/206
coord_type = (
"fract" if hasattr(attributes, "fractional_site_positions") else "Cartn"
)
cif += (
"loop_\n"
" _atom_site_type_symbol\n" # species.chemical_symbols
" _atom_site_label\n" # species.name + unique int
" _atom_site_occupancy\n" # species.concentration
f" _atom_site_{coord_type}_x\n" # cartesian_site_positions
f" _atom_site_{coord_type}_y\n" # cartesian_site_positions
f" _atom_site_{coord_type}_z\n" # cartesian_site_positions
" _atom_site_thermal_displace_type\n" # Set to 'Biso'
" _atom_site_B_iso_or_equiv\n" # Set to 1.0:f
)
if coord_type == "fract":
sites, _ = pad_positions(attributes.fractional_site_positions)
else:
sites, _ = pad_positions(attributes.cartesian_site_positions)
species: Dict[str, OptimadeStructureSpecies] = {
species.name: species for species in attributes.species
}
symbol_occurences = {}
for site_number in range(attributes.nsites):
species_name = attributes.species_at_sites[site_number]
site = sites[site_number]
current_species = species[species_name]
for index, symbol in enumerate(current_species.chemical_symbols):
if symbol == "vacancy":
continue
if symbol in symbol_occurences:
symbol_occurences[symbol] += 1
else:
symbol_occurences[symbol] = 1
label = f"{symbol}{symbol_occurences[symbol]}"
cif += (
f" {symbol} {label} {current_species.concentration[index]:6.4f} {site[0]:8.5f} "
f"{site[1]:8.5f} {site[2]:8.5f} {'Biso':4} {'1.000':6}\n"
)
return cif