Bases: ABC, ModelFactoryMixin

Main synthesizer class.

This class cannot be directly instanciated because of the specificities between RegularSynthesizer, TimeSeriesSynthesizer or MultiTableSynthesizer sample methods.

Methods

• fit: train a synthesizer instance.
• sample: request synthetic data.
• status: current status of the synthesizer instance.

Note

The synthesizer instance is created in the backend only when the fit method is called.

Parameters:

Name	Type	Description	Default
client	Client	(optional) Client to connect to the backend	None

Source code in ydata/sdk/synthesizers/synthesizer.py

@typechecked
class BaseSynthesizer(ABC, ModelFactoryMixin):
    """Main synthesizer class.

    This class cannot be directly instanciated because of the specificities between [`RegularSynthesizer`][ydata.sdk.synthesizers.RegularSynthesizer], [`TimeSeriesSynthesizer`][ydata.sdk.synthesizers.TimeSeriesSynthesizer] or [`MultiTableSynthesizer`][ydata.sdk.synthesizers.MultiTableSynthesizer] `sample` methods.

    Methods
    -------
    - `fit`: train a synthesizer instance.
    - `sample`: request synthetic data.
    - `status`: current status of the synthesizer instance.

    Note:
            The synthesizer instance is created in the backend only when the `fit` method is called.

    Arguments:
        client (Client): (optional) Client to connect to the backend
    """

    def __init__(
            self, uid: Optional[UID] = None, name: Optional[str] = None,
            project: Optional[Project] = None, client: Optional[Client] = None):
        self._init_common(client=client)
        self._model = mSynthesizer(uid=uid, name=name or str(uuid4()))
        self._project = project

    @init_client
    def _init_common(self, client: Optional[Client] = None):
        self._client = client
        self._logger = create_logger(__name__, level=LOG_LEVEL)

    @property
    def project(self) -> Project:
        return self._project or self._client.project

    def fit(self, X: Union[DataSource, pdDataFrame],
            privacy_level: PrivacyLevel = PrivacyLevel.HIGH_FIDELITY,
            datatype: Optional[Union[DataSourceType, str]] = None,
            sortbykey: Optional[Union[str, List[str]]] = None,
            entities: Optional[Union[str, List[str]]] = None,
            generate_cols: Optional[List[str]] = None,
            exclude_cols: Optional[List[str]] = None,
            dtypes: Optional[Dict[str, Union[str, DataType]]] = None,
            target: Optional[str] = None,
            anonymize: Optional[dict] = None,
            condition_on: Optional[List[str]] = None) -> None:
        """Fit the synthesizer.

        The synthesizer accepts as training dataset either a pandas [`DataFrame`][pandas.DataFrame] directly or a YData [`DataSource`][ydata.sdk.datasources.DataSource].
        When the training dataset is a pandas [`DataFrame`][pandas.DataFrame], the argument `datatype` is required as it cannot be deduced.

        The argument`sortbykey` is mandatory for [`TimeSeries`][ydata.sdk.datasources.DataSourceType.TIMESERIES].

        By default, if `generate_cols` or `exclude_cols` are not specified, all columns are generated by the synthesizer.
        The argument `exclude_cols` has precedence over `generate_cols`, i.e. a column `col` will not be generated if it is in both list.

        Arguments:
            X (Union[DataSource, pandas.DataFrame]): Training dataset
            privacy_level (PrivacyLevel): Synthesizer privacy level (defaults to high fidelity)
            datatype (Optional[Union[DataSourceType, str]]): (optional) Dataset datatype - required if `X` is a [`pandas.DataFrame`][pandas.DataFrame]
            sortbykey (Union[str, List[str]]): (optional) column(s) to use to sort timeseries datasets
            entities (Union[str, List[str]]): (optional) columns representing entities ID
            generate_cols (List[str]): (optional) columns that should be synthesized
            exclude_cols (List[str]): (optional) columns that should not be synthesized
            dtypes (Dict[str, Union[str, DataType]]): (optional) datatype mapping that will overwrite the datasource metadata column datatypes
            target (Optional[str]): (optional) Target for the dataset
            name (Optional[str]): (optional) Synthesizer instance name
            anonymize (Optional[str]): (optional) fields to anonymize and the anonymization strategy
            condition_on: (Optional[List[str]]): (optional) list of features to condition upon
        """
        if self._already_fitted():
            raise AlreadyFittedError()

        datatype = DataSourceType(datatype)

        dataset_attrs = self._init_datasource_attributes(
            sortbykey, entities, generate_cols, exclude_cols, dtypes)
        self._validate_datasource_attributes(X, dataset_attrs, datatype, target)

        # If the training data is a pandas dataframe, we first need to create a data source and then the instance
        if isinstance(X, pdDataFrame):
            if X.empty:
                raise EmptyDataError("The DataFrame is empty")
            self._logger.info('creating local connector with pandas dataframe')
            connector = LocalConnector.create(
                source=X, project=self._project, client=self._client)
            self._logger.info(
                f'created local connector. creating datasource with {connector}')
            _X = LocalDataSource(connector=connector, project=self._project,
                                 datatype=datatype, client=self._client)
            self._logger.info(f'created datasource {_X}')
        else:
            _X = X

        if dsState(_X.status.state) != dsState.AVAILABLE:
            raise DataSourceNotAvailableError(
                f"The datasource '{_X.uid}' is not available (status = {_X.status})")

        if isinstance(dataset_attrs, dict):
            dataset_attrs = DataSourceAttrs(**dataset_attrs)

        self._fit_from_datasource(
            X=_X, datatype=datatype, dataset_attrs=dataset_attrs, target=target,
            anonymize=anonymize, privacy_level=privacy_level, condition_on=condition_on)

    @staticmethod
    def _init_datasource_attributes(
            sortbykey: Optional[Union[str, List[str]]],
            entities: Optional[Union[str, List[str]]],
            generate_cols: Optional[List[str]],
            exclude_cols: Optional[List[str]],
            dtypes: Optional[Dict[str, Union[str, DataType]]]) -> DataSourceAttrs:
        dataset_attrs = {
            'sortbykey': sortbykey if sortbykey is not None else [],
            'entities': entities if entities is not None else [],
            'generate_cols': generate_cols if generate_cols is not None else [],
            'exclude_cols': exclude_cols if exclude_cols is not None else [],
            'dtypes': {k: DataType(v) for k, v in dtypes.items()} if dtypes is not None else {}
        }
        return DataSourceAttrs(**dataset_attrs)

    @staticmethod
    def _validate_datasource_attributes(X: Union[DataSource, pdDataFrame], dataset_attrs: DataSourceAttrs, datatype: DataSourceType, target: Optional[str]):
        columns = []
        if isinstance(X, pdDataFrame):
            columns = X.columns
            if datatype is None:
                raise DataTypeMissingError(
                    "Argument `datatype` is mandatory for pandas.DataFrame training data")
        else:
            columns = [c.name for c in X.metadata.columns]

        if target is not None and target not in columns:
            raise DataSourceAttrsError(
                "Invalid target: column '{target}' does not exist")

        if datatype == DataSourceType.TIMESERIES:
            if not dataset_attrs.sortbykey:
                raise DataSourceAttrsError(
                    "The argument `sortbykey` is mandatory for timeseries datasource.")

        invalid_fields = {}
        for field, v in dataset_attrs.dict().items():
            field_columns = v if field != 'dtypes' else v.keys()
            not_in_cols = [c for c in field_columns if c not in columns]
            if len(not_in_cols) > 0:
                invalid_fields[field] = not_in_cols

        if len(invalid_fields) > 0:
            error_msgs = ["\t- Field '{}': columns {} do not exist".format(
                f, ', '.join(v)) for f, v in invalid_fields.items()]
            raise DataSourceAttrsError(
                "The dataset attributes are invalid:\n {}".format('\n'.join(error_msgs)))

    @staticmethod
    def _metadata_to_payload(
        datatype: DataSourceType, ds_metadata: Metadata,
        dataset_attrs: Optional[DataSourceAttrs] = None, target: Optional[str] = None
    ) -> dict:
        """Transform a the metadata and dataset attributes into a valid
        payload.

        Arguments:
            datatype (DataSourceType): datasource type
            ds_metadata (Metadata): datasource metadata object
            dataset_attrs ( Optional[DataSourceAttrs] ): (optional) Dataset attributes
            target (Optional[str]): (optional) target column name

        Returns:
            metadata payload dictionary
        """

        columns = [
            {
                'name': c.name,
                'generation': True and c.name not in dataset_attrs.exclude_cols,
                'dataType': DataType(dataset_attrs.dtypes[c.name]).value if c.name in dataset_attrs.dtypes else c.datatype,
                'varType': c.vartype,
            }
            for c in ds_metadata.columns]

        metadata = {
            'columns': columns,
            'target': target
        }

        if dataset_attrs is not None:
            if datatype == DataSourceType.TIMESERIES:
                metadata['sortBy'] = [c for c in dataset_attrs.sortbykey]
                metadata['entity'] = [c for c in dataset_attrs.entities]

        return metadata

    def _fit_from_datasource(
        self,
        X: DataSource,
        datatype: DataSourceType,
        privacy_level: Optional[PrivacyLevel] = None,
        dataset_attrs: Optional[DataSourceAttrs] = None,
        target: Optional[str] = None,
        anonymize: Optional[dict] = None,
        condition_on: Optional[List[str]] = None
    ) -> None:
        payload = self._create_payload()

        payload['dataSourceUID'] = X.uid

        if privacy_level:
            payload['privacyLevel'] = privacy_level.value

        if X.metadata is not None:
            payload['metadata'] = self._metadata_to_payload(
                datatype, X.metadata, dataset_attrs, target)

        payload['type'] = str(datatype.value)

        if anonymize is not None:
            payload["extraData"]["anonymize"] = anonymize
        if condition_on is not None:
            payload["extraData"]["condition_on"] = condition_on

        response = self._client.post(
            '/synthesizer/', json=payload, project=self._project)
        data = response.json()
        self._model = mSynthesizer(**data)
        while self._check_fitting_not_finished(self.status):
            self._logger.info('Training the synthesizer...')
            sleep(BACKOFF)

    def _create_payload(self) -> dict:
        payload = {
            'extraData': {}
        }

        if self._model and self._model.name:
            payload['name'] = self._model.name

        return payload

    def _check_fitting_not_finished(self, status: Status) -> bool:
        self._logger.debug(f'checking status {status}')

        if Status.State(status.state) in [Status.State.READY, Status.State.REPORT]:
            return False

        self._logger.debug(f'status not ready yet {status.state}')

        if status.prepare and PrepareState(status.prepare.state) == PrepareState.FAILED:
            raise FittingError('Could not train the synthesizer')

        if status.training and TrainingState(status.training.state) == TrainingState.FAILED:
            raise FittingError('Could not train the synthesizer')

        return True

    @abstractmethod
    def sample(self) -> pdDataFrame:
        """Abstract method to sample from a synthesizer."""

    def _sample(self, payload: Dict) -> pdDataFrame:
        """Sample from a synthesizer.

        Arguments:
            payload (dict): payload configuring the sample request

        Returns:
            pandas `DataFrame`
        """
        response = self._client.post(
            f"/synthesizer/{self.uid}/sample", json=payload, project=self._project)

        data: Dict = response.json()
        sample_uid = data.get('uid')
        sample_status = None
        while sample_status not in ['finished', 'failed']:
            self._logger.info('Sampling from the synthesizer...')
            response = self._client.get(
                f'/synthesizer/{self.uid}/history', project=self._project)
            history: Dict = response.json()
            sample_data = next((s for s in history if s.get('uid') == sample_uid), None)
            sample_status = sample_data.get('status', {}).get('state')
            sleep(BACKOFF)

        response = self._client.get_static_file(
            f'/synthesizer/{self.uid}/sample/{sample_uid}/sample.csv', project=self._project)
        data = StringIO(response.content.decode())
        return read_csv(data)

    @property
    def uid(self) -> UID:
        """Get the status of a synthesizer instance.

        Returns:
            Synthesizer status
        """
        if not self._is_initialized():
            return Status.State.NOT_INITIALIZED

        return self._model.uid

    @property
    def status(self) -> Status:
        """Get the status of a synthesizer instance.

        Returns:
            Synthesizer status
        """
        if not self._is_initialized():
            return Status.not_initialized()

        try:
            self = self.get()
            return self._model.status
        except Exception:  # noqa: PIE786
            return Status.unknown()

    def get(self):
        assert self._is_initialized() and self._model.uid, InputError(
            "Please provide the synthesizer `uid`")

        response = self._client.get(f'/synthesizer/{self.uid}', project=self._project)
        data = response.json()
        self._model = mSynthesizer(**data)

        return self

    @staticmethod
    @init_client
    def list(client: Optional[Client] = None) -> SynthesizersList:
        """List the synthesizer instances.

        Arguments:
            client (Client): (optional) Client to connect to the backend

        Returns:
            List of synthesizers
        """
        def __process_data(data: list) -> list:
            to_del = ['metadata', 'report', 'mode']
            for e in data:
                for k in to_del:
                    e.pop(k, None)
            return data

        response = client.get('/synthesizer')
        data: list = response.json()
        data = __process_data(data)

        return SynthesizersList(data)

    def _is_initialized(self) -> bool:
        """Determine if a synthesizer is instanciated or not.

        Returns:
            True if the synthesizer is instanciated
        """
        return self._model is not None

    def _already_fitted(self) -> bool:
        """Determine if a synthesizer is already fitted.

        Returns:
            True if the synthesizer is instanciated
        """

        return self._is_initialized() and \
            (self._model.status is not None
             and self._model.status.training is not None
             and self._model.status.training.state is not [TrainingState.PREPARING])

    @staticmethod
    def _resolve_api_status(api_status: Dict) -> Status:
        """Determine the status of the Synthesizer.

        The status of the synthesizer instance is determined by the state of
        its different components.

        Arguments:
            api_status (dict): json from the endpoint GET /synthesizer

        Returns:
            Synthesizer Status
        """
        status = Status(api_status.get('state', Status.UNKNOWN.name))
        if status == Status.PREPARE:
            if PrepareState(api_status.get('prepare', {}).get(
                    'state', PrepareState.UNKNOWN.name)) == PrepareState.FAILED:
                return Status.FAILED
        elif status == Status.TRAIN:
            if TrainingState(api_status.get('training', {}).get(
                    'state', TrainingState.UNKNOWN.name)) == TrainingState.FAILED:
                return Status.FAILED
        elif status == Status.REPORT:
            return Status.READY
        return status

status: Status property

Get the status of a synthesizer instance.

Returns:

Type	Description
Status	Synthesizer status

uid: UID property

Get the status of a synthesizer instance.

Returns:

Type	Description
UID	Synthesizer status

fit(X, privacy_level=PrivacyLevel.HIGH_FIDELITY, datatype=None, sortbykey=None, entities=None, generate_cols=None, exclude_cols=None, dtypes=None, target=None, anonymize=None, condition_on=None)

Fit the synthesizer.

The synthesizer accepts as training dataset either a pandas DataFrame directly or a YData DataSource. When the training dataset is a pandas DataFrame, the argument datatype is required as it cannot be deduced.

The argumentsortbykey is mandatory for TimeSeries.

By default, if generate_cols or exclude_cols are not specified, all columns are generated by the synthesizer. The argument exclude_cols has precedence over generate_cols, i.e. a column col will not be generated if it is in both list.

Parameters:

Name	Type	Description	Default
X	Union[DataSource, DataFrame]	Training dataset	required
privacy_level	PrivacyLevel	Synthesizer privacy level (defaults to high fidelity)	HIGH_FIDELITY
datatype	Optional[Union[DataSourceType, str]]	(optional) Dataset datatype - required if X is a pandas.DataFrame	None
sortbykey	Union[str, List[str]]	(optional) column(s) to use to sort timeseries datasets	None
entities	Union[str, List[str]]	(optional) columns representing entities ID	None
generate_cols	List[str]	(optional) columns that should be synthesized	None
exclude_cols	List[str]	(optional) columns that should not be synthesized	None
dtypes	Dict[str, Union[str, DataType]]	(optional) datatype mapping that will overwrite the datasource metadata column datatypes	None
target	Optional[str]	(optional) Target for the dataset	None
name	Optional[str]	(optional) Synthesizer instance name	required
anonymize	Optional[str]	(optional) fields to anonymize and the anonymization strategy	None
condition_on	Optional[List[str]]	(Optional[List[str]]): (optional) list of features to condition upon	None

Source code in ydata/sdk/synthesizers/synthesizer.py

def fit(self, X: Union[DataSource, pdDataFrame],
        privacy_level: PrivacyLevel = PrivacyLevel.HIGH_FIDELITY,
        datatype: Optional[Union[DataSourceType, str]] = None,
        sortbykey: Optional[Union[str, List[str]]] = None,
        entities: Optional[Union[str, List[str]]] = None,
        generate_cols: Optional[List[str]] = None,
        exclude_cols: Optional[List[str]] = None,
        dtypes: Optional[Dict[str, Union[str, DataType]]] = None,
        target: Optional[str] = None,
        anonymize: Optional[dict] = None,
        condition_on: Optional[List[str]] = None) -> None:
    """Fit the synthesizer.

    The synthesizer accepts as training dataset either a pandas [`DataFrame`][pandas.DataFrame] directly or a YData [`DataSource`][ydata.sdk.datasources.DataSource].
    When the training dataset is a pandas [`DataFrame`][pandas.DataFrame], the argument `datatype` is required as it cannot be deduced.

    The argument`sortbykey` is mandatory for [`TimeSeries`][ydata.sdk.datasources.DataSourceType.TIMESERIES].

    By default, if `generate_cols` or `exclude_cols` are not specified, all columns are generated by the synthesizer.
    The argument `exclude_cols` has precedence over `generate_cols`, i.e. a column `col` will not be generated if it is in both list.

    Arguments:
        X (Union[DataSource, pandas.DataFrame]): Training dataset
        privacy_level (PrivacyLevel): Synthesizer privacy level (defaults to high fidelity)
        datatype (Optional[Union[DataSourceType, str]]): (optional) Dataset datatype - required if `X` is a [`pandas.DataFrame`][pandas.DataFrame]
        sortbykey (Union[str, List[str]]): (optional) column(s) to use to sort timeseries datasets
        entities (Union[str, List[str]]): (optional) columns representing entities ID
        generate_cols (List[str]): (optional) columns that should be synthesized
        exclude_cols (List[str]): (optional) columns that should not be synthesized
        dtypes (Dict[str, Union[str, DataType]]): (optional) datatype mapping that will overwrite the datasource metadata column datatypes
        target (Optional[str]): (optional) Target for the dataset
        name (Optional[str]): (optional) Synthesizer instance name
        anonymize (Optional[str]): (optional) fields to anonymize and the anonymization strategy
        condition_on: (Optional[List[str]]): (optional) list of features to condition upon
    """
    if self._already_fitted():
        raise AlreadyFittedError()

    datatype = DataSourceType(datatype)

    dataset_attrs = self._init_datasource_attributes(
        sortbykey, entities, generate_cols, exclude_cols, dtypes)
    self._validate_datasource_attributes(X, dataset_attrs, datatype, target)

    # If the training data is a pandas dataframe, we first need to create a data source and then the instance
    if isinstance(X, pdDataFrame):
        if X.empty:
            raise EmptyDataError("The DataFrame is empty")
        self._logger.info('creating local connector with pandas dataframe')
        connector = LocalConnector.create(
            source=X, project=self._project, client=self._client)
        self._logger.info(
            f'created local connector. creating datasource with {connector}')
        _X = LocalDataSource(connector=connector, project=self._project,
                             datatype=datatype, client=self._client)
        self._logger.info(f'created datasource {_X}')
    else:
        _X = X

    if dsState(_X.status.state) != dsState.AVAILABLE:
        raise DataSourceNotAvailableError(
            f"The datasource '{_X.uid}' is not available (status = {_X.status})")

    if isinstance(dataset_attrs, dict):
        dataset_attrs = DataSourceAttrs(**dataset_attrs)

    self._fit_from_datasource(
        X=_X, datatype=datatype, dataset_attrs=dataset_attrs, target=target,
        anonymize=anonymize, privacy_level=privacy_level, condition_on=condition_on)

list(client=None) staticmethod

List the synthesizer instances.

Parameters:

Name	Type	Description	Default
client	Client	(optional) Client to connect to the backend	None

Returns:

Type	Description
SynthesizersList	List of synthesizers

Source code in ydata/sdk/synthesizers/synthesizer.py

@staticmethod
@init_client
def list(client: Optional[Client] = None) -> SynthesizersList:
    """List the synthesizer instances.

    Arguments:
        client (Client): (optional) Client to connect to the backend

    Returns:
        List of synthesizers
    """
    def __process_data(data: list) -> list:
        to_del = ['metadata', 'report', 'mode']
        for e in data:
            for k in to_del:
                e.pop(k, None)
        return data

    response = client.get('/synthesizer')
    data: list = response.json()
    data = __process_data(data)

    return SynthesizersList(data)

sample() abstractmethod

Abstract method to sample from a synthesizer.

Source code in ydata/sdk/synthesizers/synthesizer.py

@abstractmethod
def sample(self) -> pdDataFrame:
    """Abstract method to sample from a synthesizer."""

PrivacyLevel

Bases: StringEnum

Privacy level exposed to the end-user.

BALANCED_PRIVACY_FIDELITY = 'BALANCED_PRIVACY_FIDELITY' class-attribute instance-attribute

Balanced privacy/fidelity

HIGH_FIDELITY = 'HIGH_FIDELITY' class-attribute instance-attribute

High fidelity

HIGH_PRIVACY = 'HIGH_PRIVACY' class-attribute instance-attribute

High privacy