maml.describers package

Describer for converting (structural) objects into models-readable numeric vectors or tensors.

class maml.describers.BPSymmetryFunctions(cutoff: float, r_etas: ndarray, r_shift: ndarray, a_etas: ndarray, zetas: ndarray, lambdas: ndarray, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Behler-Parrinello symmetry function to describe the local environment of each atom.

Reference: @article{behler2007generalized,

title={Generalized neural-network representation of

high-dimensional potential-energy surfaces},

author={Behler, J{“o}rg and Parrinello, Michele}, journal={Physical review letters}, volume={98}, number={14}, pages={146401}, year={2007}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

_fc(r: float)

Cutoff function to decay the symmetry functions at vicinity of radial cutoff.

• Parameters r (float) – The pair distance.

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

transform_one(structure: Structure)

• Parameters structure (Structure) – Pymatgen Structure object.

class maml.describers.BispectrumCoefficients(rcutfac: float, twojmax: int, element_profile: dict, quadratic: bool = False, pot_fit: bool = False, include_stress: bool = False, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Bispectrum coefficients to describe the local environment of each atom. Lammps is required to perform this computation.

Reference: @article{bartok2010gaussian,

title={Gaussian approximation potentials: The

accuracy of quantum mechanics, without the electrons},

author={Bart{‘o}k, Albert P and Payne, Mike C

and Kondor, Risi and Cs{'a}nyi, G{'a}bor},

journal={Physical review letters}, volume={104}, number={13}, pages={136403}, year={2010}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

property feature_dim(: int | Non )

Bispectrum feature dimension.

property subscripts(: lis )

The subscripts (2j1, 2j2, 2j) of all bispectrum components involved.

transform_one(structure: Structure)

• Parameters structure (Structure) – Pymatgen Structure object.

class maml.describers.CoulombEigenSpectrum(max_atoms: int | None = None, **kwargs)

Bases: BaseDescriber

Get the Coulomb Eigen Spectrum describers.

Reference: @article{rupp2012fast,

title={Fast and accurate modeling of molecular

atomization energies with machine learning},

author={Rupp, Matthias and Tkatchenko, Alexandre and M{“u}ller,

Klaus-Robert and Von Lilienfeld, O Anatole},

journal={Physical review letters}, volume={108}, number={5}, pages={058301}, year={2012}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

transform_one(mol: Molecule)

• Parameters mol (Molecule) – pymatgen molecule.

Returns: np.ndarray the eigen value vectors of Coulob matrix

class maml.describers.CoulombMatrix(random_seed: int | None = None, max_atoms: int | None = None, is_ravel: bool = True, **kwargs)

Bases: BaseDescriber

Coulomb Matrix to describe structure.

Reference: @article{rupp2012fast,

title={Fast and accurate modeling of molecular

atomization energies with machine learning},

author={Rupp, Matthias and Tkatchenko, Alexandre and M{“u}ller,

Klaus-Robert and Von Lilienfeld, O Anatole},

journal={Physical review letters}, volume={108}, number={5}, pages={058301}, year={2012}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

static _get_columb_mat(s: Molecule | Structure)

• Parameters s (Molecule/Structure) – input Molecule or Structure. Structure is not advised since the feature will depend on the supercell size.
• Returns Coulomb matrix of the structure

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

get_coulomb_mat(s: Molecule | Structure)

• Parameters s (Molecule/Structure) – input Molecule or Structure. Structure is not advised since the feature will depend on the supercell size
• Returns Coulomb matrix of the structure.

transform_one(s: Molecule | Structure)

• Parameters s (Molecule/Structure) – pymatgen Molecule or Structure, Structure is not advised since the features will depend on supercell size.
• Returns pandas.DataFrame. The column is index of the structure, which is 0 for single input df[0] returns the serials of coulomb_mat raval

class maml.describers.DistinctSiteProperty(properties: list[str], symprec: float = 0.1, wyckoffs: list[str] | None = None, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Constructs a describers based on properties of distinct sites in a structure. For now, this assumes that there is only one type of species in a particular Wyckoff site.

Reference: @article{ye2018deep,

title={Deep neural networks for accurate predictions of crystal stability}, author={Ye, Weike and Chen, Chi and Wang, Zhenbin and

Chu, Iek-Heng and Ong, Shyue Ping}, journal={Nature communications}, volume={9}, number={1}, pages={1–6}, year={2018}, publisher={Nature Publishing Group}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

supported_properties(_ = [‘mendeleev_no’, ‘electrical_resistivity’, ‘velocity_of_sound’, ‘reflectivity’, ‘refractive_index’, ‘poissons_ratio’, ‘molar_volume’, ‘thermal_conductivity’, ‘boiling_point’, ‘melting_point’, ‘critical_temperature’, ‘superconduction_temperature’, ‘liquid_range’, ‘bulk_modulus’, ‘youngs_modulus’, ‘brinell_hardness’, ‘rigidity_modulus’, ‘mineral_hardness’, ‘vickers_hardness’, ‘density_of_solid’, ‘atomic_radius_calculated’, ‘van_der_waals_radius’, ‘coefficient_of_linear_thermal_expansion’, ‘ground_state_term_symbol’, ‘valence’, ‘Z’, ‘X’, ‘atomic_mass’, ‘block’, ‘row’, ‘group’, ‘atomic_radius’, ‘average_ionic_radius’, ‘average_cationic_radius’, ‘average_anionic_radius’, ‘metallic_radius’, ‘ionic_radii’, ‘oxi_state’, ‘max_oxidation_state’, ‘min_oxidation_state’, ‘is_transition_metal’, ‘is_alkali’, ‘is_alkaline’, ‘is_chalcogen’, ‘is_halogen’, ‘is_lanthanoid’, ‘is_metal’, ‘is_metalloid’, ‘is_noble_gas’, ‘is_post_transition_metal’, ‘is_quadrupolar’, ‘is_rare_earth_metal’, ‘is_actinoid’_ )

transform_one(structure: Structure)

• Parameters structure (pymatgen Structure) – pymatgen structure for descriptor computation.
• Returns pd.DataFrame that contains the distinct position labeled features

class maml.describers.ElementProperty(*args, **kwargs)

Bases: BaseDescriber

Class to calculate elemental property attributes.

To initialize quickly, use the from_preset() method.

Features: Based on the statistics of the data_source chosen, computed by element stoichiometry. The format generally is:

“{data source} {statistic} {property}”

For example:

“PymetgenData range X” # Range of electronegativity from Pymatgen data

For a list of all statistics, see the PropertyStats documentation; for a list of all attributes available for a given data_source, see the documentation for the data sources (e.g., PymatgenData, MagpieData, MatscholarElementData, etc.).

• Parameters
  • data_source (AbstractData* or *str) – source from which to retrieve element property data (or use str for preset: “pymatgen”, “magpie”, or “deml”)
  • features (list* of *strings) – List of elemental properties to use (these must be supported by data_source)
  • stats (list* of *strings) – a list of weighted statistics to compute to for each property (see PropertyStats for available stats)

abc_impl( = <_abc.abc_data object )

classmethod _get_param_names()

Get parameter names for the estimator

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘composition_ )

classmethod from_preset(name: str, **kwargs)

Wrap matminer_wrapper’s from_preset function.

get_params(deep=False)

Get parameters for this estimator.

• Parameters deep (bool*, *default=True) – If True, will return the parameters for this estimator and contained subobjects that are estimators.
• Returns params – Parameter names mapped to their values.
• Return type dict

transform_one(obj: Any)

Featurize to transform_one.

class maml.describers.ElementStats(element_properties: dict, stats: list[str] | None = None, property_names: list[str] | None = None, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Element statistics. The allowed stats are accessed via ALLOWED_STATS class attributes. If the stats have multiple parameters, the positional arguments are separated by ::, e.g., moment::1::None.

ALLOWED_STATS(_ = [‘max’, ‘min’, ‘range’, ‘mode’, ‘mean_absolute_deviation’, ‘mean_absolute_error’, ‘moment’, ‘mean’, ‘inverse_mean’, ‘average’, ‘std’, ‘skewness’, ‘kurtosis’, ‘geometric_mean’, ‘power_mean’, ‘shifted_geometric_mean’, ‘harmonic_mean’_ )

AVAILABLE_DATA(_ = [‘megnet_1’, ‘megnet_3’, ‘megnet_l2’, ‘megnet_ion_l2’, ‘megnet_l3’, ‘megnet_ion_l3’, ‘megnet_l4’, ‘megnet_ion_l4’, ‘megnet_l8’, ‘megnet_ion_l8’, ‘megnet_l16’, ‘megnet_ion_l16’, ‘megnet_l32’, ‘megnet_ion_l32’_ )

abc_impl( = <_abc.abc_data object )

static _reduce_dimension(element_properties, property_names, num_dim: int | None = None, reduction_algo: str | None = ‘pca’, reduction_params: dict | None = None)

Reduce the feature dimension by reduction_algo.

• Parameters
  • element_properties (dict) – dictionary of elemental/specie propeprties
  • property_names (list) – list of property names
  • num_dim (int) – number of dimension to keep
  • reduction_algo (str) – algorithm for dimensional reduction, currently support pca, kpca
  • reduction_params (dict) – kwargs for reduction algorithm

Returns: new element_properties and property_names

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘composition_ )

classmethod from_data(data_name: list[str] | str, stats: list[str] | None = None, **kwargs)

ElementalStats from existing data file.

• Parameters
  • data_name (str* of list of *str) – data name. Current supported data are available from ElementStats.AVAILABLE_DATA
  • stats (list) – list of stats, use ElementStats.ALLOWED_STATS to check available stats
  • **kwargs – Passthrough to class init.

Returns: ElementStats instance

classmethod from_file(filename: str, stats: list[str] | None = None, **kwargs)

ElementStats from a json file of element property dictionary.

The keys required are:

element_properties property_names

• Parameters
  • filename (str) – filename
  • stats (list) – list of stats, check ElementStats.ALLOWED_STATS for supported stats. The stats that support additional Keyword args, use ‘:’ to separate the args. For example, ‘moment:0:None’ will calculate moment stats with order=0, and max_order=None.
  • **kwargs – Passthrough to class init.

Returns: ElementStats class

transform_one(obj: Structure | str | Composition)

Transform one object, the object can be string, Compostion or Structure.

• Parameters obj (str/Composition/Structure) – object to transform

Returns: pd.DataFrame with property names as column names

class maml.describers.M3GNetStructure(model_path: str | None = None, **kwargs)

Bases: BaseDescriber

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

transform_one(structure: Structure | Molecule)

Transform structure/molecule objects into features :param structure: target object structure or molecule :type structure: Structure/Molecule

Returns: np.array features.

class maml.describers.MEGNetSite(name: str | object | None = None, level: int | None = None, **kwargs)

Bases: BaseDescriber

Use megnet pre-trained models as featurizer to get atomic features.

Reference: @article{chen2019graph,title={Graph networks as a universal machine

learning framework for molecules and crystals}, author={Chen, Chi and Ye, Weike and Zuo, Yunxing and

Zheng, Chen and Ong, Shyue Ping},

journal={Chemistry of Materials}, volume={31}, number={9}, pages={3564–3572}, year={2019},publisher={ACS Publications}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

transform_one(obj: Structure | Molecule)

Get megnet site features from structure object.

• Parameters obj (structure* or *molecule) – pymatgen structure or molecules

Returns:

class maml.describers.MEGNetStructure(name: str | object | None = None, mode: str = ‘site_stats’, level: int | None = None, stats: list | None = None, **kwargs)

Bases: BaseDescriber

Use megnet pre-trained models as featurizer to get structural features. There are two methods to get structural descriptors from megnet models.

mode:

‘site_stats’: Calculate the site features, and then use maml.utils.stats to compute the feature-wise

    statistics. This requires the specification of level

‘site_readout’: Use the atomic features at the readout stage
‘final’: Use the concatenated atom, bond and global features

Reference: @article{chen2019graph,title={Graph networks as a universal machine

learning framework for molecules and crystals}, author={Chen, Chi and Ye, Weike and Zuo, Yunxing and

Zheng, Chen and Ong, Shyue Ping},

journal={Chemistry of Materials}, volume={31}, number={9}, pages={3564–3572}, year={2019},publisher={ACS Publications}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

transform_one(obj: Structure | Molecule)

Transform structure/molecule objects into features :param obj: target object structure or molecule. :type obj: Structure/Molecule

Returns: pd.DataFrame features

class maml.describers.RadialDistributionFunction(r_min: float = 0.0, r_max: float = 10.0, n_grid: int = 101, sigma: float = 0.0)

Bases: object

Calculator for radial distribution function.

static _get_specie_density(structure: Structure)

get_site_coordination(structure: Structure)

Get site wise coordination :param structure: pymatgen Structure. :type structure: Structure

Returns: r, cns where cns is a list of dictionary with specie_pair: pair_cn key:value pairs

get_site_rdf(structure: Structure)

• Parameters structure (Structure) – pymatgen structure
• Returns r, rdfs, r is the radial points, and rdfs are a list of rdf dicts rdfs[0] is the rdfs of the first site. It is a dictionary of {atom_pair: pair_rdf} e.g.,

{“Sr:O”: [0, 0, 0.1, 0.2, ..]}.

get_species_coordination(structure: Structure, ref_species: list | None = None, species: list | None = None)

Get specie-wise coordination number :param structure: target structure :type structure: Structure :param ref_species: the reference species.

The rdfs are calculated with these species at the center

• Parameters species (list* of species or *just single specie str) – the species that we are interested in. The rdfs are calculated on these species.

Returns:

get_species_rdf(structure: Structure, ref_species: list | None = None, species: list | None = None)

Get specie-wise rdf :param structure: target structure :type structure: Structure :param ref_species: the reference species.

The rdfs are calculated with these species at the center

• Parameters species (list* of species or *just single specie str) – the species that we are interested in. The rdfs are calculated on these species.

Returns:

class maml.describers.RandomizedCoulombMatrix(random_seed: int | None = None, is_ravel: bool = True, **kwargs)

Bases: CoulombMatrix

Randomized CoulombMatrix.

Reference: @article{montavon2013machine,

title={Machine learning of molecular electronic properties

in chemical compound space},

author={Montavon, Gr{‘e}goire and Rupp, Matthias and Gobre,

Vivekanand and Vazquez-Mayagoitia, Alvaro and Hansen, Katja
and Tkatchenko, Alexandre and M{"u}ller, Klaus-Robert and
Von Lilienfeld, O Anatole},

journal={New Journal of Physics}, volume={15}, number={9},pages={095003}, year={2013},publisher={IOP Publishing}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

get_randomized_coulomb_mat(s: Molecule | Structure)

Returns the randomized matrix (i) take an arbitrary valid Coulomb matrix C (ii) compute the norm of each row of this Coulomb matrix: row_norms (iii) draw a zero-mean unit-variance noise vector ε of the same

size as row_norms.

1. permute the rows and columns of C with the same permutation

that sorts row_norms + ε.

• Parameters s (Molecule/Structure) – pymatgen Molecule or Structure, Structure is not advised since the features will depend on supercell size
• Returns pd.DataFrame randomized Coulomb matrix

transform_one(s: Molecule | Structure)

Transform one structure to descriptors :param s: pymatgen Molecule or Structure, Structure is not

advised since the features will depend on supercell size.

Returns: pandas dataframe descriptors

class maml.describers.SiteElementProperty(feature_dict: dict | None = None, output_weights: bool = False, **kwargs)

Bases: BaseDescriber

Site specie property describers. For a structure or composition, return an unordered set of site specie properties.

abc_impl( = <_abc.abc_data object )

static _get_keys(c: Composition)

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

property feature_dim()

Feature dimension.

transform_one(obj: str | Composition | Structure | Molecule)

Transform one object to features.

• Parameters obj (str/Composition/Structure/Molecule) – object to transform
• Returns features array

class maml.describers.SmoothOverlapAtomicPosition(cutoff: float, l_max: int = 8, n_max: int = 8, atom_sigma: float = 0.5, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Smooth overlap of atomic positions (SOAP) to describe the local environment of each atom.

Reference: @article{bartok2013representing,

title={On representing chemical environments}, author={Bart{‘o}k, Albert P and Kondor, Risi and Cs{‘a}nyi, G{‘a}bor}, journal={Physical Review B}, volume={87}, number={18}, pages={184115}, year={2013}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

transform_one(structure: Structure)

• Parameters structure (Structure) – Pymatgen Structure object.

class maml.describers.SortedCoulombMatrix(random_seed: int | None = None, is_ravel: bool = True, **kwargs)

Bases: CoulombMatrix

Sorted CoulombMatrix.

Reference: @inproceedings{montavon2012learning,

title={Learning invariant representations

of molecules for atomization energy prediction},

author={Montavon, Gr{‘e}goire and Hansen, Katja

and Fazli, Siamac and Rupp, Matthias and Biegler,
Franziska and Ziehe, Andreas and Tkatchenko, Alexandre
and Lilienfeld, Anatole V and M{"u}ller, Klaus-Robert},

booktitle={Advances in neural information processing systems}, pages={440–448}, year={2012}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

get_sorted_coulomb_mat(s: Molecule | Structure)

Returns the matrix sorted by the row norm.

• Parameters s (Molecule/Structure) – pymatgen Molecule or Structure, Structure is not advised since the features will depend on supercell size
• Returns pd.DataFrame, sorted Coulomb matrix

transform_one(s: Molecule | Structure)

Transform one structure into descriptor :param s: pymatgen Molecule or Structure, Structure is not

advised since the features will depend on supercell size.

Returns: pd.DataFrame descriptors

maml.describers.wrap_matminer_describer(cls_name: str, wrapped_class: Any, obj_conversion: Callable, describer_type: Any | None = None)

Wrapper of matminer_wrapper describers.

• Parameters
  • cls_name (str) – new class name
  • wrapped_class (class object) – matminer_wrapper BaseFeaturizer
  • obj_conversion (callable) – function to convert objects into desired object type within transform_one
  • describer_type (object) – object type.

Returns: maml describers class

maml.describers._composition module

Compositional describers.

class maml.describers._composition.ElementStats(element_properties: dict, stats: list[str] | None = None, property_names: list[str] | None = None, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Element statistics. The allowed stats are accessed via ALLOWED_STATS class attributes. If the stats have multiple parameters, the positional arguments are separated by ::, e.g., moment::1::None.

ALLOWED_STATS(_ = [‘max’, ‘min’, ‘range’, ‘mode’, ‘mean_absolute_deviation’, ‘mean_absolute_error’, ‘moment’, ‘mean’, ‘inverse_mean’, ‘average’, ‘std’, ‘skewness’, ‘kurtosis’, ‘geometric_mean’, ‘power_mean’, ‘shifted_geometric_mean’, ‘harmonic_mean’_ )

AVAILABLE_DATA(_ = [‘megnet_1’, ‘megnet_3’, ‘megnet_l2’, ‘megnet_ion_l2’, ‘megnet_l3’, ‘megnet_ion_l3’, ‘megnet_l4’, ‘megnet_ion_l4’, ‘megnet_l8’, ‘megnet_ion_l8’, ‘megnet_l16’, ‘megnet_ion_l16’, ‘megnet_l32’, ‘megnet_ion_l32’_ )

abc_impl( = <_abc.abc_data object )

static _reduce_dimension(element_properties, property_names, num_dim: int | None = None, reduction_algo: str | None = ‘pca’, reduction_params: dict | None = None)

Reduce the feature dimension by reduction_algo.

• Parameters
  • element_properties (dict) – dictionary of elemental/specie propeprties
  • property_names (list) – list of property names
  • num_dim (int) – number of dimension to keep
  • reduction_algo (str) – algorithm for dimensional reduction, currently support pca, kpca
  • reduction_params (dict) – kwargs for reduction algorithm

Returns: new element_properties and property_names

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘composition_ )

classmethod from_data(data_name: list[str] | str, stats: list[str] | None = None, **kwargs)

ElementalStats from existing data file.

• Parameters
  • data_name (str* of list of *str) – data name. Current supported data are available from ElementStats.AVAILABLE_DATA
  • stats (list) – list of stats, use ElementStats.ALLOWED_STATS to check available stats
  • **kwargs – Passthrough to class init.

Returns: ElementStats instance

classmethod from_file(filename: str, stats: list[str] | None = None, **kwargs)

ElementStats from a json file of element property dictionary.

The keys required are:

element_properties property_names

• Parameters
  • filename (str) – filename
  • stats (list) – list of stats, check ElementStats.ALLOWED_STATS for supported stats. The stats that support additional Keyword args, use ‘:’ to separate the args. For example, ‘moment:0:None’ will calculate moment stats with order=0, and max_order=None.
  • **kwargs – Passthrough to class init.

Returns: ElementStats class

transform_one(obj: Structure | str | Composition)

Transform one object, the object can be string, Compostion or Structure.

• Parameters obj (str/Composition/Structure) – object to transform

Returns: pd.DataFrame with property names as column names

maml.describers._composition._is_element_or_specie(s: str)

maml.describers._composition._keys_are_elements(dic: dict)

maml.describers._m3gnet module

class maml.describers._m3gnet.M3GNetStructure(model_path: str | None = None, **kwargs)

Bases: BaseDescriber

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

transform_one(structure: Structure | Molecule)

Transform structure/molecule objects into features :param structure: target object structure or molecule :type structure: Structure/Molecule

Returns: np.array features.

maml.describers._matminer module

Wrapper for matminer_wrapper featurizers.

maml.describers._matminer.wrap_matminer_describer(cls_name: str, wrapped_class: Any, obj_conversion: Callable, describer_type: Any | None = None)

Wrapper of matminer_wrapper describers.

• Parameters
  • cls_name (str) – new class name
  • wrapped_class (class object) – matminer_wrapper BaseFeaturizer
  • obj_conversion (callable) – function to convert objects into desired object type within transform_one
  • describer_type (object) – object type.

Returns: maml describers class

maml.describers._megnet module

MEGNet-based describers.

exception maml.describers._megnet.MEGNetNotFound()

Bases: Exception

MEGNet not found exception.

class maml.describers._megnet.MEGNetSite(name: str | object | None = None, level: int | None = None, **kwargs)

Bases: BaseDescriber

Use megnet pre-trained models as featurizer to get atomic features.

Reference: @article{chen2019graph,title={Graph networks as a universal machine

learning framework for molecules and crystals}, author={Chen, Chi and Ye, Weike and Zuo, Yunxing and

Zheng, Chen and Ong, Shyue Ping},

journal={Chemistry of Materials}, volume={31}, number={9}, pages={3564–3572}, year={2019},publisher={ACS Publications}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

transform_one(obj: Structure | Molecule)

Get megnet site features from structure object.

• Parameters obj (structure* or *molecule) – pymatgen structure or molecules

Returns:

class maml.describers._megnet.MEGNetStructure(name: str | object | None = None, mode: str = ‘site_stats’, level: int | None = None, stats: list | None = None, **kwargs)

Bases: BaseDescriber

Use megnet pre-trained models as featurizer to get structural features. There are two methods to get structural descriptors from megnet models.

mode:

‘site_stats’: Calculate the site features, and then use maml.utils.stats to compute the feature-wise

    statistics. This requires the specification of level

‘site_readout’: Use the atomic features at the readout stage
‘final’: Use the concatenated atom, bond and global features

Reference: @article{chen2019graph,title={Graph networks as a universal machine

learning framework for molecules and crystals}, author={Chen, Chi and Ye, Weike and Zuo, Yunxing and

Zheng, Chen and Ong, Shyue Ping},

journal={Chemistry of Materials}, volume={31}, number={9}, pages={3564–3572}, year={2019},publisher={ACS Publications}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

transform_one(obj: Structure | Molecule)

Transform structure/molecule objects into features :param obj: target object structure or molecule. :type obj: Structure/Molecule

Returns: pd.DataFrame features

maml.describers._megnet._load_model(name: str | object | None = None)

maml.describers._rdf module

Radial distribution functions for site features. This was originally written in pymatgen-diffusion.

class maml.describers._rdf.RadialDistributionFunction(r_min: float = 0.0, r_max: float = 10.0, n_grid: int = 101, sigma: float = 0.0)

Bases: object

Calculator for radial distribution function.

static _get_specie_density(structure: Structure)

get_site_coordination(structure: Structure)

Get site wise coordination :param structure: pymatgen Structure. :type structure: Structure

Returns: r, cns where cns is a list of dictionary with specie_pair: pair_cn key:value pairs

get_site_rdf(structure: Structure)

• Parameters structure (Structure) – pymatgen structure
• Returns r, rdfs, r is the radial points, and rdfs are a list of rdf dicts rdfs[0] is the rdfs of the first site. It is a dictionary of {atom_pair: pair_rdf} e.g.,

{“Sr:O”: [0, 0, 0.1, 0.2, ..]}.

get_species_coordination(structure: Structure, ref_species: list | None = None, species: list | None = None)

Get specie-wise coordination number :param structure: target structure :type structure: Structure :param ref_species: the reference species.

The rdfs are calculated with these species at the center

• Parameters species (list* of species or *just single specie str) – the species that we are interested in. The rdfs are calculated on these species.

Returns:

get_species_rdf(structure: Structure, ref_species: list | None = None, species: list | None = None)

Get specie-wise rdf :param structure: target structure :type structure: Structure :param ref_species: the reference species.

The rdfs are calculated with these species at the center

• Parameters species (list* of species or *just single specie str) – the species that we are interested in. The rdfs are calculated on these species.

Returns:

maml.describers._rdf._dist_to_counts(d: ndarray, r_min: float = 0.0, r_max: float = 8.0, n_grid: int = 100)

Convert a distance array for counts in the bin :param d: distance array :type d: 1D np.ndarray :param r_min: minimal radius :type r_min: float :param r_max: maximum radius :type r_max: float

• Returns 1D array of counts in the bins centered on grid.

maml.describers._rdf.get_pair_distances(structure: Structure, r_max: float = 8.0)

Get pair distances from structure. The output will be a list of of dictionary, for example [{“specie”: “Mo”, “neighbors”: {“S”: [1.0, 2.0, …], “Fe”: [1.2, 3.0, …]}}, {“specie”: “Fe”, “neighbors”: {“Mo”: [1.0, 3.0, …]}}] it will be fairly easy to construct radial distribution func, etc from here.

• Parameters
  • structure (Structure) – pymatgen Structure
  • r_max (float) – maximum radius to consider

Returns:

maml.describers._site module

This module provides local environment describers.

class maml.describers._site.BPSymmetryFunctions(cutoff: float, r_etas: ndarray, r_shift: ndarray, a_etas: ndarray, zetas: ndarray, lambdas: ndarray, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Behler-Parrinello symmetry function to describe the local environment of each atom.

Reference: @article{behler2007generalized,

title={Generalized neural-network representation of

high-dimensional potential-energy surfaces},

author={Behler, J{“o}rg and Parrinello, Michele}, journal={Physical review letters}, volume={98}, number={14}, pages={146401}, year={2007}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

_fc(r: float)

Cutoff function to decay the symmetry functions at vicinity of radial cutoff.

• Parameters r (float) – The pair distance.

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

transform_one(structure: Structure)

• Parameters structure (Structure) – Pymatgen Structure object.

class maml.describers._site.BispectrumCoefficients(rcutfac: float, twojmax: int, element_profile: dict, quadratic: bool = False, pot_fit: bool = False, include_stress: bool = False, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Bispectrum coefficients to describe the local environment of each atom. Lammps is required to perform this computation.

Reference: @article{bartok2010gaussian,

title={Gaussian approximation potentials: The

accuracy of quantum mechanics, without the electrons},

author={Bart{‘o}k, Albert P and Payne, Mike C

and Kondor, Risi and Cs{'a}nyi, G{'a}bor},

journal={Physical review letters}, volume={104}, number={13}, pages={136403}, year={2010}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

property feature_dim(: int | Non )

Bispectrum feature dimension.

property subscripts(: lis )

The subscripts (2j1, 2j2, 2j) of all bispectrum components involved.

transform_one(structure: Structure)

• Parameters structure (Structure) – Pymatgen Structure object.

class maml.describers._site.MEGNetSite(name: str | object | None = None, level: int | None = None, **kwargs)

Bases: BaseDescriber

Use megnet pre-trained models as featurizer to get atomic features.

Reference: @article{chen2019graph,title={Graph networks as a universal machine

learning framework for molecules and crystals}, author={Chen, Chi and Ye, Weike and Zuo, Yunxing and

Zheng, Chen and Ong, Shyue Ping},

journal={Chemistry of Materials}, volume={31}, number={9}, pages={3564–3572}, year={2019},publisher={ACS Publications}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

transform_one(obj: Structure | Molecule)

Get megnet site features from structure object.

• Parameters obj (structure* or *molecule) – pymatgen structure or molecules

Returns:

class maml.describers._site.SiteElementProperty(feature_dict: dict | None = None, output_weights: bool = False, **kwargs)

Bases: BaseDescriber

Site specie property describers. For a structure or composition, return an unordered set of site specie properties.

abc_impl( = <_abc.abc_data object )

static _get_keys(c: Composition)

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

property feature_dim()

Feature dimension.

transform_one(obj: str | Composition | Structure | Molecule)

Transform one object to features.

• Parameters obj (str/Composition/Structure/Molecule) – object to transform
• Returns features array

class maml.describers._site.SmoothOverlapAtomicPosition(cutoff: float, l_max: int = 8, n_max: int = 8, atom_sigma: float = 0.5, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Smooth overlap of atomic positions (SOAP) to describe the local environment of each atom.

Reference: @article{bartok2013representing,

title={On representing chemical environments}, author={Bart{‘o}k, Albert P and Kondor, Risi and Cs{‘a}nyi, G{‘a}bor}, journal={Physical Review B}, volume={87}, number={18}, pages={184115}, year={2013}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘site_ )

transform_one(structure: Structure)

• Parameters structure (Structure) – Pymatgen Structure object.

maml.describers._spectrum module

Spectrum describers.

maml.describers._structure module

Structure-wise describers. These describers include structural information.

class maml.describers._structure.CoulombEigenSpectrum(max_atoms: int | None = None, **kwargs)

Bases: BaseDescriber

Get the Coulomb Eigen Spectrum describers.

Reference: @article{rupp2012fast,

title={Fast and accurate modeling of molecular

atomization energies with machine learning},

author={Rupp, Matthias and Tkatchenko, Alexandre and M{“u}ller,

Klaus-Robert and Von Lilienfeld, O Anatole},

journal={Physical review letters}, volume={108}, number={5}, pages={058301}, year={2012}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

transform_one(mol: Molecule)

• Parameters mol (Molecule) – pymatgen molecule.

Returns: np.ndarray the eigen value vectors of Coulob matrix

class maml.describers._structure.CoulombMatrix(random_seed: int | None = None, max_atoms: int | None = None, is_ravel: bool = True, **kwargs)

Bases: BaseDescriber

Coulomb Matrix to describe structure.

Reference: @article{rupp2012fast,

title={Fast and accurate modeling of molecular

atomization energies with machine learning},

author={Rupp, Matthias and Tkatchenko, Alexandre and M{“u}ller,

Klaus-Robert and Von Lilienfeld, O Anatole},

journal={Physical review letters}, volume={108}, number={5}, pages={058301}, year={2012}, publisher={APS}}

abc_impl( = <_abc.abc_data object )

static _get_columb_mat(s: Molecule | Structure)

• Parameters s (Molecule/Structure) – input Molecule or Structure. Structure is not advised since the feature will depend on the supercell size.
• Returns Coulomb matrix of the structure

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

get_coulomb_mat(s: Molecule | Structure)

• Parameters s (Molecule/Structure) – input Molecule or Structure. Structure is not advised since the feature will depend on the supercell size
• Returns Coulomb matrix of the structure.

transform_one(s: Molecule | Structure)

• Parameters s (Molecule/Structure) – pymatgen Molecule or Structure, Structure is not advised since the features will depend on supercell size.
• Returns pandas.DataFrame. The column is index of the structure, which is 0 for single input df[0] returns the serials of coulomb_mat raval

class maml.describers._structure.DistinctSiteProperty(properties: list[str], symprec: float = 0.1, wyckoffs: list[str] | None = None, feature_batch: str = ‘pandas_concat’, **kwargs)

Bases: BaseDescriber

Constructs a describers based on properties of distinct sites in a structure. For now, this assumes that there is only one type of species in a particular Wyckoff site.

Reference: @article{ye2018deep,

title={Deep neural networks for accurate predictions of crystal stability}, author={Ye, Weike and Chen, Chi and Wang, Zhenbin and

Chu, Iek-Heng and Ong, Shyue Ping}, journal={Nature communications}, volume={9}, number={1}, pages={1–6}, year={2018}, publisher={Nature Publishing Group}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

supported_properties(_ = [‘mendeleev_no’, ‘electrical_resistivity’, ‘velocity_of_sound’, ‘reflectivity’, ‘refractive_index’, ‘poissons_ratio’, ‘molar_volume’, ‘thermal_conductivity’, ‘boiling_point’, ‘melting_point’, ‘critical_temperature’, ‘superconduction_temperature’, ‘liquid_range’, ‘bulk_modulus’, ‘youngs_modulus’, ‘brinell_hardness’, ‘rigidity_modulus’, ‘mineral_hardness’, ‘vickers_hardness’, ‘density_of_solid’, ‘atomic_radius_calculated’, ‘van_der_waals_radius’, ‘coefficient_of_linear_thermal_expansion’, ‘ground_state_term_symbol’, ‘valence’, ‘Z’, ‘X’, ‘atomic_mass’, ‘block’, ‘row’, ‘group’, ‘atomic_radius’, ‘average_ionic_radius’, ‘average_cationic_radius’, ‘average_anionic_radius’, ‘metallic_radius’, ‘ionic_radii’, ‘oxi_state’, ‘max_oxidation_state’, ‘min_oxidation_state’, ‘is_transition_metal’, ‘is_alkali’, ‘is_alkaline’, ‘is_chalcogen’, ‘is_halogen’, ‘is_lanthanoid’, ‘is_metal’, ‘is_metalloid’, ‘is_noble_gas’, ‘is_post_transition_metal’, ‘is_quadrupolar’, ‘is_rare_earth_metal’, ‘is_actinoid’_ )

transform_one(structure: Structure)

• Parameters structure (pymatgen Structure) – pymatgen structure for descriptor computation.
• Returns pd.DataFrame that contains the distinct position labeled features

class maml.describers._structure.RandomizedCoulombMatrix(random_seed: int | None = None, is_ravel: bool = True, **kwargs)

Bases: CoulombMatrix

Randomized CoulombMatrix.

Reference: @article{montavon2013machine,

title={Machine learning of molecular electronic properties

in chemical compound space},

author={Montavon, Gr{‘e}goire and Rupp, Matthias and Gobre,

Vivekanand and Vazquez-Mayagoitia, Alvaro and Hansen, Katja
and Tkatchenko, Alexandre and M{"u}ller, Klaus-Robert and
Von Lilienfeld, O Anatole},

journal={New Journal of Physics}, volume={15}, number={9},pages={095003}, year={2013},publisher={IOP Publishing}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

get_randomized_coulomb_mat(s: Molecule | Structure)

Returns the randomized matrix (i) take an arbitrary valid Coulomb matrix C (ii) compute the norm of each row of this Coulomb matrix: row_norms (iii) draw a zero-mean unit-variance noise vector ε of the same

size as row_norms.

1. permute the rows and columns of C with the same permutation

that sorts row_norms + ε.

• Parameters s (Molecule/Structure) – pymatgen Molecule or Structure, Structure is not advised since the features will depend on supercell size
• Returns pd.DataFrame randomized Coulomb matrix

transform_one(s: Molecule | Structure)

Transform one structure to descriptors :param s: pymatgen Molecule or Structure, Structure is not

advised since the features will depend on supercell size.

Returns: pandas dataframe descriptors

class maml.describers._structure.SortedCoulombMatrix(random_seed: int | None = None, is_ravel: bool = True, **kwargs)

Bases: CoulombMatrix

Sorted CoulombMatrix.

Reference: @inproceedings{montavon2012learning,

title={Learning invariant representations

of molecules for atomization energy prediction},

author={Montavon, Gr{‘e}goire and Hansen, Katja

and Fazli, Siamac and Rupp, Matthias and Biegler,
Franziska and Ziehe, Andreas and Tkatchenko, Alexandre
and Lilienfeld, Anatole V and M{"u}ller, Klaus-Robert},

booktitle={Advances in neural information processing systems}, pages={440–448}, year={2012}}

abc_impl( = <_abc.abc_data object )

sklearn_auto_wrap_output_keys( = {‘transform’_ )

describer_type(_ = ‘structure_ )

get_sorted_coulomb_mat(s: Molecule | Structure)

Returns the matrix sorted by the row norm.

• Parameters s (Molecule/Structure) – pymatgen Molecule or Structure, Structure is not advised since the features will depend on supercell size
• Returns pd.DataFrame, sorted Coulomb matrix

transform_one(s: Molecule | Structure)

Transform one structure into descriptor :param s: pymatgen Molecule or Structure, Structure is not

advised since the features will depend on supercell size.

Returns: pd.DataFrame descriptors