pymatgen.analysis.chemenv.coordination_environments.coordination_geometry_finder module

class AbstractGeometry(central_site=None, bare_coords=None, centering_type='standard', include_central_site_in_centroid=False)

Bases: object

Class used to describe a geometry (perfect or distorted)

Constructor for the abstract geometry :param central_site: Coordinates of the central site :param bare_coords: Coordinates of the neighbors of the central site :param centering_type: How to center the abstract geometry :param include_central_site_in_centroid: When the centering is on the centroid, the central site is included

if this parameter is set to True.

Raise:ValueError if the parameters are not consistent

classmethod from_cg(cg, centering_type='standard', include_central_site_in_centroid=False)

points_wcs_csc(permutation=None)

points_wcs_ctwcc(permutation=None)

points_wcs_ctwocc(permutation=None)

points_wocs_csc(permutation=None)

points_wocs_ctwcc(permutation=None)

points_wocs_ctwocc(permutation=None)

class LocalGeometryFinder(permutations_safe_override=False, plane_ordering_override=True, debug_level=None, plane_safe_permutations=False, only_symbols=None)

Bases: object

Main class used to find the local environments in a structure

Constructor for the LocalGeometryFinder, initializes the list of coordination geometries :param permutations_safe_override: If set to True, all permutations are tested (very time-consuming for large coordination numbers!) :param plane_ordering_override: If set to False, the ordering of the points in the plane is disabled

BVA_DISTANCE_SCALE_FACTORS = {'experimental': 1.0, 'GGA_relaxed': 1.015, 'LDA_relaxed': 0.995}

DEFAULT_BVA_DISTANCE_SCALE_FACTOR = 1.0

DEFAULT_SPG_ANALYZER_OPTIONS = {'symprec': 0.001, 'angle_tolerance': 5}

DEFAULT_STRATEGY = <pymatgen.analysis.chemenv.coordination_environments.chemenv_strategies.MultiWeightsChemenvStrategy object>

STRUCTURE_REFINEMENT_NONE = 'none'

STRUCTURE_REFINEMENT_REFINED = 'refined'

STRUCTURE_REFINEMENT_SYMMETRIZED = 'symmetrized'

compute_coordination_environments(structure, indices=None, only_cations=True, strategy=<pymatgen.analysis.chemenv.coordination_environments.chemenv_strategies.MultiWeightsChemenvStrategy object>, valences='bond-valence-analysis', initial_structure_environments=None)

compute_structure_environments(excluded_atoms=None, only_atoms=None, only_cations=True, only_indices=None, maximum_distance_factor=None, minimum_angle_factor=None, max_cn=None, min_cn=None, only_symbols=None, valences='undefined', additional_conditions=None, info=None, timelimit=None, initial_structure_environments=None, recompute=None)

Computes and returns the StructureEnvironments object containing all the information about the coordination environments in the structure :param excluded_atoms: Atoms for which the coordination geometries does not have to be identified :param only_atoms: If not set to None, atoms for which the coordination geometries have to be identified :return: The StructureEnvironments object containing all the information about the coordination environments in the structure

coordination_geometry_symmetry_measures(coordination_geometry, tested_permutations=False, points_perfect=None)

Returns the symmetry measures of a given coordination_geometry for a set of permutations depending on the permutation setup. Depending on the parameters of the LocalGeometryFinder and on the coordination

geometry, different methods are called.

Parameters:coordination_geometry – Coordination geometry for which the symmetry measures are looked for Returns:the symmetry measures of a given coordination_geometry for a set of permutations Raise:NotImplementedError if the permutation_setup does not exists

coordination_geometry_symmetry_measures_fallback_random(coordination_geometry, NRANDOM=10, points_perfect=None)

Returns the symmetry measures for a random set of permutations for the coordination geometry “coordination_geometry”. Fallback implementation for the plane separation algorithms measures of each permutation

Parameters:

• coordination_geometry – The coordination geometry to be investigated
• NRANDOM – Number of random permutations to be tested

Returns:

The symmetry measures for the given coordination geometry for each permutation investigated

coordination_geometry_symmetry_measures_safe_override(coordination_geometry)

Returns the symmetry measures for a set of permutations (whose setup depends on the coordination geometry) for the coordination geometry “coordination_geometry”. Standard implementatison looking for the symmetry measures of each permutation

Parameters:coordination_geometry – The coordination geometry to be investigated Returns:The symmetry measures for the given coordination geometry for each permutation investigated

coordination_geometry_symmetry_measures_separation_plane(coordination_geometry, separation_plane_algo, testing=False, tested_permutations=False, points_perfect=None)

Returns the symmetry measures of the given coordination geometry “coordination_geometry” using separation facets to reduce the complexity of the system. Caller to the refined 2POINTS, 3POINTS and other … :param coordination_geometry: The coordination geometry to be investigated :return: The symmetry measures for the given coordination geometry for each plane and permutation investigated

coordination_geometry_symmetry_measures_standard(coordination_geometry, algo, points_perfect=None)

Returns the symmetry measures for a set of permutations (whose setup depends on the coordination geometry) for the coordination geometry “coordination_geometry”. Standard implementation looking for the symmetry measures of each permutation

Parameters:coordination_geometry – The coordination geometry to be investigated Returns:The symmetry measures for the given coordination geometry for each permutation investigated

get_coordination_symmetry_measures(only_minimum=True, all_csms=True)

Returns the continuous symmetry measures of the current local geometry in a dictionary. :return: the continuous symmetry measures of the current local geometry in a dictionary.

get_structure()

Returns the pymatgen Structure that has been setup for the identification of geometries (the initial one might have been refined/symmetrized using the SpaceGroupAnalyzer). :return: The pymatgen Structure that has been setup for the identification of geometries (the initial one might have been refined/symmetrized using the SpaceGroupAnalyzer).

set_structure(lattice, species, coords, coords_are_cartesian)

Sets up the pymatgen structure for which the coordination geometries have to be identified starting from the lattice, the species and the coordinates :param lattice: The lattice of the structure :param species: The species on the sites :param coords: The coordinates of the sites :param coords_are_cartesian: If set to True, the coordinates are given in cartesian coordinates

setup_explicit_indices_local_geometry(explicit_indices)

Sets up explicit indices for the local geometry, for testing purposes :param explicit_indices: explicit indices for the neighbors (set of numbers from 0 to CN-1 in a given order)

setup_local_geometry(isite, coords)

Sets up the AbstractGeometry for the local geometry of site with index isite. :param isite: Index of the site for which the local geometry has to be set up :param coords: The coordinates of the (local) neighbors

setup_ordered_indices_local_geometry(coordination)

Sets up ordered indices for the local geometry, for testing purposes :param coordination: coordination of the local geometry

setup_parameter(parameter, value)

Setup of one specific parameter to the given value. The other parameters are unchanged. See setup_parameters method for the list of possible parameters :param parameter: Parameter to setup/update :param value: Value of the parameter

setup_parameters(centering_type='standard', include_central_site_in_centroid=False, bva_distance_scale_factor=None, structure_refinement='refined', spg_analyzer_options=None)

Setup of the parameters for the coordination geometry finder. A reference point for the geometries has to be chosen. This can be the centroid of the structure (including or excluding the atom for which the coordination geometry is looked for) or the atom itself. In the ‘standard’ centering_type, the reference point is the central atom for coordination numbers 1, 2, 3 and 4 and the centroid for coordination numbers > 4. :param centering_type: Type of the reference point (centering) ‘standard’, ‘centroid’ or ‘central_site’ :param include_central_site_in_centroid: In case centering_type is ‘centroid’, the central site is included if

this value is set to True.

Parameters:

• bva_distance_scale_factor – Scaling factor for the bond valence analyzer (this might be different whether the structure is an experimental one, an LDA or a GGA relaxed one, or any other relaxation scheme (where under- or over-estimation of bond lengths is known).
• structure_refinement – Refinement of the structure. Can be “none”, “refined” or “symmetrized”.
• spg_analyzer_options – Options for the SpaceGroupAnalyzer (dictionary specifying “symprec” and “angle_tolerance”. See pymatgen’s SpaceGroupAnalyzer for more information.

setup_random_indices_local_geometry(coordination)

Sets up random indices for the local geometry, for testing purposes :param coordination: coordination of the local geometry

setup_random_structure(coordination)

Sets up a purely random structure with a given coordination. :param coordination: coordination number for the random structure

setup_structure(structure)

Sets up the structure for which the coordination geometries have to be identified. The structure is analyzed with the space group analyzer and a refined structure is used :param structure: A pymatgen Structure :param

setup_test_perfect_environment(symbol, randomness=False, max_random_dist=0.1, symbol_type='mp_symbol', indices='RANDOM', random_translation='NONE', random_rotation='NONE', random_scale='NONE')

update_nb_set_environments(se, isite, cn, inb_set, nb_set, recompute=False)

find_rotation(points_distorted, points_perfect)

This finds the rotation matrix that aligns the (distorted) set of points “points_distorted” with respect to the (perfect) set of points “points_perfect” in a least-square sense. :param points_distorted: List of points describing a given (distorted) polyhedron for which the rotation that

aligns these points in a least-square sense to the set of perfect points “points_perfect”

Parameters:points_perfect – List of “perfect” points describing a given model polyhedron. Returns:The rotation matrix

find_scaling_factor(points_distorted, points_perfect, rot)

This finds the scaling factor between the (distorted) set of points “points_distorted” and the (perfect) set of points “points_perfect” in a least-square sense. :param points_distorted: List of points describing a given (distorted) polyhedron for which the scaling factor has

to be obtained.

Parameters:

• points_perfect – List of “perfect” points describing a given model polyhedron.
• rot – The rotation matrix

Returns:

The scaling factor between the two structures and the rotated set of (distorted) points.

symmetry_measure(points_distorted, points_perfect)

Computes the continuous symmetry measure of the (distorted) set of points “points_distorted” with respect to the (perfect) set of points “points_perfect”. :param points_distorted: List of points describing a given (distorted) polyhedron for which the symmetry measure

has to be computed with respect to the model polyhedron described by the list of points “points_perfect”.

Parameters:points_perfect – List of “perfect” points describing a given model polyhedron. Returns:The continuous symmetry measure of the distorted polyhedron with respect to the perfect polyhedron