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Transformers

cesnet_tszoo.utils.transformer

Transformer

Bases: ABC

Base class for transformers, used for transforming data.

This class serves as the foundation for creating custom transformers. To implement a custom transformer, this class is recommended to be subclassed and extended.

Example:

import numpy as np

class LogTransformer(Transformer):

    def fit(self, data: np.ndarray):
        ...

    def partial_fit(self, data: np.ndarray) -> None:
        ...

    def transform(self, data: np.ndarray):
        log_data = np.ma.log(data)

        return log_data.filled(np.nan)

    def inverse_transform(self, transformed_data):
        return np.exp(transformed_data)
Source code in cesnet_tszoo\utils\transformer.py 
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class Transformer(ABC):
    """
    Base class for transformers, used for transforming data.

    This class serves as the foundation for creating custom transformers. To implement a custom transformer, this class is recommended to be subclassed and extended.

    Example:

        import numpy as np

        class LogTransformer(Transformer):

            def fit(self, data: np.ndarray):
                ...

            def partial_fit(self, data: np.ndarray) -> None:
                ...

            def transform(self, data: np.ndarray):
                log_data = np.ma.log(data)

                return log_data.filled(np.nan)

            def inverse_transform(self, transformed_data):
                return np.exp(transformed_data)                
    """

    @abstractmethod
    def fit(self, data: np.ndarray) -> None:
        """
        Sets the transformer values for a given time series part.

        This method must be implemented if using multiple transformers that have not been pre-fitted.

        Parameters:
            data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.  
        """
        ...

    @abstractmethod
    def partial_fit(self, data: np.ndarray) -> None:
        """
        Partially sets the transformer values for a given time series part.

        This method must be implemented if using a single transformer that is not pre-fitted for all time series, or when using pre-fitted transformer(s) with `partial_fit_initialized_transformers` set to `True`.

        Parameters:
            data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.        
        """
        ...

    @abstractmethod
    def transform(self, data: np.ndarray) -> np.ndarray:
        """
        Transforms the input data for a given time series part.

        This method must always be implemented.

        Parameters:
            data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.  

        Returns:
            The transformed data, with the same shape as the input `(times, features)`.            
        """
        ...

    def inverse_transform(self, transformed_data: np.ndarray) -> np.ndarray:
        """
        Transforms the input transformed data to their original representation for a given time series part.

        Parameters:
            transformed_data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.  

        Returns:
            The original representation of transformed data, with the same shape as the input `(times, features)`.            
        """
        ...

fit abstractmethod 

fit(data: ndarray) -> None

Sets the transformer values for a given time series part.

This method must be implemented if using multiple transformers that have not been pre-fitted.

Parameters:

Name Type Description Default
data ndarray

A numpy array representing data for a single time series with shape (times, features) excluding any identifiers.

 required
Source code in cesnet_tszoo\utils\transformer.py 
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@abstractmethod
def fit(self, data: np.ndarray) -> None:
    """
    Sets the transformer values for a given time series part.

    This method must be implemented if using multiple transformers that have not been pre-fitted.

    Parameters:
        data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.  
    """
    ...

inverse_transform 

inverse_transform(transformed_data: ndarray) -> np.ndarray

Transforms the input transformed data to their original representation for a given time series part.

Parameters:

Name Type Description Default
transformed_data ndarray

A numpy array representing data for a single time series with shape (times, features) excluding any identifiers.

required

Returns:

Type Description
ndarray

The original representation of transformed data, with the same shape as the input (times, features).
Source code in cesnet_tszoo\utils\transformer.py 
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def inverse_transform(self, transformed_data: np.ndarray) -> np.ndarray:
    """
    Transforms the input transformed data to their original representation for a given time series part.

    Parameters:
        transformed_data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.  

    Returns:
        The original representation of transformed data, with the same shape as the input `(times, features)`.            
    """
    ...

partial_fit abstractmethod 

partial_fit(data: ndarray) -> None

Partially sets the transformer values for a given time series part.

This method must be implemented if using a single transformer that is not pre-fitted for all time series, or when using pre-fitted transformer(s) with partial_fit_initialized_transformers set to True.

Parameters:

Name Type Description Default
data ndarray

A numpy array representing data for a single time series with shape (times, features) excluding any identifiers.

 required
Source code in cesnet_tszoo\utils\transformer.py 
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@abstractmethod
def partial_fit(self, data: np.ndarray) -> None:
    """
    Partially sets the transformer values for a given time series part.

    This method must be implemented if using a single transformer that is not pre-fitted for all time series, or when using pre-fitted transformer(s) with `partial_fit_initialized_transformers` set to `True`.

    Parameters:
        data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.        
    """
    ...

transform abstractmethod 

transform(data: ndarray) -> np.ndarray

Transforms the input data for a given time series part.

This method must always be implemented.

Parameters:

Name Type Description Default
data ndarray

A numpy array representing data for a single time series with shape (times, features) excluding any identifiers.

required

Returns:

Type Description
ndarray

The transformed data, with the same shape as the input (times, features).
Source code in cesnet_tszoo\utils\transformer.py 
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@abstractmethod
def transform(self, data: np.ndarray) -> np.ndarray:
    """
    Transforms the input data for a given time series part.

    This method must always be implemented.

    Parameters:
        data: A numpy array representing data for a single time series with shape `(times, features)` excluding any identifiers.  

    Returns:
        The transformed data, with the same shape as the input `(times, features)`.            
    """
    ...

LogTransformer

Bases: Transformer

Tranforms data with natural logarithm. Zero or invalid values are set to np.nan.

Corresponds to enum TransformerType.LOG_TRANSFORMER or literal log_transformer.

Source code in cesnet_tszoo\utils\transformer.py 
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class LogTransformer(Transformer):
    """
    Tranforms data with natural logarithm. Zero or invalid values are set to `np.nan`.

    Corresponds to enum [`TransformerType.LOG_TRANSFORMER`][cesnet_tszoo.utils.enums.TransformerType] or literal `log_transformer`.
    """

    def fit(self, data: np.ndarray):
        ...

    def partial_fit(self, data: np.ndarray) -> None:
        ...

    def transform(self, data: np.ndarray):
        log_data = np.ma.log(data)

        return log_data.filled(np.nan)

    def inverse_transform(self, transformed_data):
        return np.exp(transformed_data)

L2Normalizer

Bases: Transformer

Tranforms data using Scikit L2Normalizer.

Corresponds to enum TransformerType.L2_NORMALIZER or literal l2_normalizer.

Source code in cesnet_tszoo\utils\transformer.py 
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class L2Normalizer(Transformer):
    """
    Tranforms data using Scikit [`L2Normalizer`](https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.Normalizer.html).

    Corresponds to enum [`TransformerType.L2_NORMALIZER`][cesnet_tszoo.utils.enums.TransformerType] or literal `l2_normalizer`.
    """

    def __init__(self):
        self.transformer = sk.Normalizer(norm="l2")

    def fit(self, data: np.ndarray):
        ...

    def partial_fit(self, data: np.ndarray) -> None:
        ...

    def transform(self, data: np.ndarray):
        return self.transformer.fit_transform(data)

    def inverse_transform(self, transformed_data):
        raise NotImplementedError("Normalizer does not support inverse_transform.")

MinMaxScaler

Bases: Transformer

Tranforms data using Scikit MinMaxScaler.

Corresponds to enum TransformerType.MIN_MAX_SCALER or literal min_max_scaler.

Source code in cesnet_tszoo\utils\transformer.py 
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class MinMaxScaler(Transformer):
    """
    Tranforms data using Scikit [`MinMaxScaler`](https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.MinMaxScaler.html).

    Corresponds to enum [`TransformerType.MIN_MAX_SCALER`][cesnet_tszoo.utils.enums.TransformerType] or literal `min_max_scaler`.
    """

    def __init__(self):
        self.transformer = sk.MinMaxScaler()

    def fit(self, data: np.ndarray) -> None:
        self.transformer.fit(data)

    def partial_fit(self, data: np.ndarray) -> None:
        self.transformer.partial_fit(data)

    def transform(self, data: np.ndarray) -> np.ndarray:
        return self.transformer.transform(data)

    def inverse_transform(self, transformed_data) -> np.ndarray:
        return self.transformer.inverse_transform(transformed_data)

StandardScaler

Bases: Transformer

Tranforms data using Scikit StandardScaler.

Corresponds to enum TransformerType.STANDARD_SCALER or literal standard_scaler.

Source code in cesnet_tszoo\utils\transformer.py 
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class StandardScaler(Transformer):
    """
    Tranforms data using Scikit [`StandardScaler`](https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.StandardScaler.html).

    Corresponds to enum [`TransformerType.STANDARD_SCALER`][cesnet_tszoo.utils.enums.TransformerType] or literal `standard_scaler`.
    """

    def __init__(self):
        self.transformer = sk.StandardScaler()

    def fit(self, data: np.ndarray) -> None:
        self.transformer.fit(data)

    def partial_fit(self, data: np.ndarray) -> None:
        self.transformer.partial_fit(data)

    def transform(self, data: np.ndarray) -> np.ndarray:
        return self.transformer.transform(data)

    def inverse_transform(self, transformed_data):
        return self.transformer.inverse_transform(transformed_data)

MaxAbsScaler

Bases: Transformer

Tranforms data using Scikit MaxAbsScaler.

Corresponds to enum TransformerType.MAX_ABS_SCALER or literal max_abs_scaler.

Source code in cesnet_tszoo\utils\transformer.py 
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class MaxAbsScaler(Transformer):
    """
    Tranforms data using Scikit [`MaxAbsScaler`](https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.MaxAbsScaler.html).

    Corresponds to enum [`TransformerType.MAX_ABS_SCALER`][cesnet_tszoo.utils.enums.TransformerType] or literal `max_abs_scaler`.
    """

    def __init__(self):
        self.transformer = sk.MaxAbsScaler()

    def fit(self, data: np.ndarray):
        self.transformer.fit(data)

    def partial_fit(self, data: np.ndarray) -> None:
        self.transformer.partial_fit(data)

    def transform(self, data: np.ndarray):
        return self.transformer.transform(data)

    def inverse_transform(self, transformed_data):
        return self.transformer.inverse_transform(transformed_data)

PowerTransformer

Bases: Transformer

Tranforms data using Scikit PowerTransformer.

Corresponds to enum TransformerType.POWER_TRANSFORMER or literal power_transformer.

partial_fit not supported

Because this transformer does not support partial_fit it can't be used when using one transformer that needs to be fitted for multiple time series.

Source code in cesnet_tszoo\utils\transformer.py 
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class PowerTransformer(Transformer):
    """
    Tranforms data using Scikit [`PowerTransformer`](https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.PowerTransformer.html).

    Corresponds to enum [`TransformerType.POWER_TRANSFORMER`][cesnet_tszoo.utils.enums.TransformerType] or literal `power_transformer`.

    !!! warning "partial_fit not supported"
        Because this transformer does not support partial_fit it can't be used when using one transformer that needs to be fitted for multiple time series.
    """

    def __init__(self):
        self.transformer = sk.PowerTransformer()

    def fit(self, data: np.ndarray):
        self.transformer.fit(data)

    def partial_fit(self, data: np.ndarray) -> None:
        raise NotImplementedError("PowerTransformer does not support partial_fit.")

    def transform(self, data: np.ndarray):
        return self.transformer.transform(data)

    def inverse_transform(self, transformed_data):
        return self.transformer.inverse_transform(transformed_data)

QuantileTransformer

Bases: Transformer

Tranforms data using Scikit QuantileTransformer.

Corresponds to enum TransformerType.QUANTILE_TRANSFORMER or literal quantile_transformer.

partial_fit not supported

Because this transformer does not support partial_fit it can't be used when using one transformer that needs to be fitted for multiple time series.

Source code in cesnet_tszoo\utils\transformer.py 
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class QuantileTransformer(Transformer):
    """
    Tranforms data using Scikit [`QuantileTransformer`](https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.QuantileTransformer.html).

    Corresponds to enum [`TransformerType.QUANTILE_TRANSFORMER`][cesnet_tszoo.utils.enums.TransformerType] or literal `quantile_transformer`.

    !!! warning "partial_fit not supported"
        Because this transformer does not support partial_fit it can't be used when using one transformer that needs to be fitted for multiple time series.    
    """

    def __init__(self):
        self.transformer = sk.QuantileTransformer()

    def fit(self, data: np.ndarray):
        self.transformer.fit(data)

    def partial_fit(self, data: np.ndarray) -> None:
        raise NotImplementedError("QuantileTransformer does not support partial_fit.")

    def transform(self, data: np.ndarray):
        return self.transformer.transform(data)

    def inverse_transform(self, transformed_data):
        return self.transformer.inverse_transform(transformed_data)

RobustScaler

Bases: Transformer

Tranforms data using Scikit RobustScaler.

Corresponds to enum TransformerType.ROBUST_SCALER or literal robust_scaler.

partial_fit not supported

Because this transformer does not support partial_fit it can't be used when using one transformer that needs to be fitted for multiple time series.

Source code in cesnet_tszoo\utils\transformer.py 
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class RobustScaler(Transformer):
    """
    Tranforms data using Scikit [`RobustScaler`](https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.RobustScaler.html).

    Corresponds to enum [`TransformerType.ROBUST_SCALER`][cesnet_tszoo.utils.enums.TransformerType] or literal `robust_scaler`.

    !!! warning "partial_fit not supported"
        Because this transformer does not support partial_fit it can't be used when using one transformer that needs to be fitted for multiple time series.    
    """

    def __init__(self):
        self.transformer = sk.RobustScaler()

    def fit(self, data: np.ndarray):
        self.transformer.fit(data)

    def partial_fit(self, data: np.ndarray) -> None:
        raise NotImplementedError("RobustScaler does not support partial_fit.")

    def transform(self, data: np.ndarray):
        return self.transformer.transform(data)

    def inverse_transform(self, transformed_data):
        return self.transformer.inverse_transform(transformed_data)