heat.preprocessing

Add the preprocessing functions to the ht.preprocessing namespace

Submodules

Package Contents

_is_2D_float_DNDarray(input)
_has_n_features(param, inputdata)
_tol_wrt_dtype(inputdata)
class StandardScaler(*, copy: bool = True, with_mean: bool = True, with_std: bool = True)

Bases: heat.TransformMixin, heat.BaseEstimator

Standardization of features to mean 0 and variance 1 by affine linear transformation; similar to sklearn.preprocessing.StandardScaler. The data set to be scaled must be stored as 2D-DNDarray of shape (n_datapoints, n_features). Shifting to mean 0 and scaling to variance 1 is applied to each feature independently.

Parameters:

  • copy (bool, default=True) – If False, try to avoid a copy and do inplace scaling instead.

  • with_mean (bool, default=True) – If True, center the data (i.e. mean = 0) before scaling.

  • with_std (bool, default=True) – If True, scale the data to variance = 1.

Variables:

  • scale (DNDarray of shape (n_features,) or None) – Per feature relative scaling of the data to achieve unit variance. Set to None (no variance scaling applied) if var = None or var below machine precision.

  • mean (DNDarray of shape (n_features,) or None) – The mean value for each feature. Equal to None when with_mean=False.

  • var (DNDarray of shape (n_features,) or None) – Featurewise variance of the given data. Equal to None when with_std=False.

fit(X: heat.DNDarray, sample_weight: heat.DNDarray | None = None) → Self

Fit StandardScaler to the given data X, i.e. compute mean and standard deviation of X to be used for later scaling.

Parameters:

  • X (DNDarray of shape (n_datapoints, n_features).) – Data used to compute the mean and standard deviation used for later featurewise scaling.

  • sample_weight (Not yet supported.) – Raises NotImplementedError.

transform(X: heat.DNDarray) → Self | heat.DNDarray

Applies standardization to input data X by centering and scaling w.r.t. mean and std previously computed and saved in StandardScaler with :meth:fit.

Parameters:

  • X (DNDarray (n_datapoints, n_features)) – The data set to be standardized.

  • copy (bool, default=None) – Copy the input X or not.

inverse_transform(Y: heat.DNDarray) → Self | heat.DNDarray

Scale back the data to the original representation, i.e. apply the inverse of :meth:transform to the input Y.

Parameters:

  • Y (DNDarray of shape (n_datapoints, n_features)) – Data to be scaled back.

  • copy (bool, default=None) – Copy the input Y or not.

class MinMaxScaler(feature_range: Tuple[float, float] = (0.0, 1.0), *, copy: bool = True, clip: bool = False)

Bases: heat.TransformMixin, heat.BaseEstimator

Min-Max-Scaler: transforms the features by scaling each feature (affine) linearly to the prescribed range; similar to sklearn.preprocessing.MinMaxScaler. The data set to be scaled must be stored as 2D-DNDarray of shape (n_datapoints, n_features).

Each feature is scaled and translated individually such that it is in the given range on the input data set, e.g. between zero and one (default).

Parameters:

  • feature_range (tuple (min, max), default=(0, 1)) – Desired range of transformed features.

  • copy (bool, default=True) – copy = False means in-place transformations whenever possible.

  • clip (Not yet supported.) – raises NotImplementedError.

Variables:

  • min (DNDarray of shape (n_features,)) – translation required per feature

  • scale (DNDarray of shape (n_features,)) – scaling required per feature

  • data_min (DNDarray of shape (n_features,)) – minimum per feature in the input data set

  • data_max (DNDarray of shape (n_features,)) – maximum per feature in the input data set

  • data_range (DNDarray of shape (n_features,)) – range per feature in the input data set

fit(X: heat.DNDarray) → Self

Fit the MinMaxScaler: i.e. compute the parameters required for later scaling.

Parameters:

X (DNDarray of shape (n_datapoints, n_features)) – data set to which scaler shall be fitted.

transform(X: heat.DNDarray) → Self | heat.DNDarray

Transform input data with MinMaxScaler: i.e. scale features of X according to feature_range.

Parameters:

X (DNDarray of shape (n_datapoints, n_features)) – Data set to be transformed.

inverse_transform(Y: heat.DNDarray) → Self | heat.DNDarray

Apply the inverse of :meth:fit.

Parameters:

Y (DNDarray of shape (n_datapoints, n_features)) – Data set to be transformed back.

class Normalizer(norm: str = 'l2', *, copy: bool = True)

Bases: heat.TransformMixin, heat.BaseEstimator

Normalizer: each data point of a data set is scaled to unit norm independently. The data set to be scaled must be stored as 2D-DNDarray of shape (n_datapoints, n_features); therefore the Normalizer scales each row to unit norm. This object is similar to sklearn.preprocessing.Normalizer.

Parameters:

  • norm ({'l1', 'l2', 'max'}, default='l2') – The norm to use to normalize the data points. norm='max' refers to the \(\ell^\infty\)-norm.

  • copy (bool, default=True) – copy=False enables in-place normalization.

Variables:

None

Notes

Normalizer is stateless and, consequently, :meth:fit is only a dummy that does not need to be called before :meth:transform. Since :meth:transform is not bijective, there is no back-transformation :meth:inverse_transform.

fit(X: heat.DNDarray) → Self

Since :object:Normalizer is stateless, this function is only a dummy.

transform(X: heat.DNDarray) → Self | heat.DNDarray

Apply Normalizer trasformation: scales each data point of the input data set X to unit norm (w.r.t. to norm).

Parameters:

  • X (DNDarray of shape (n_datapoints, n_features)) – The data set to be normalized.

  • copy (bool, default=None) – copy=False enables in-place transformation.

class MaxAbsScaler(*, copy: bool = True)

Bases: heat.TransformMixin, heat.BaseEstimator

MaxAbsScaler: scale each feature of a given data set linearly by its maximum absolute value. The underyling data set to be scaled is assumed to be stored as a 2D-DNDarray of shape (n_datapoints, n_features); this routine is similar to sklearn.preprocessing.MaxAbsScaler.

Each feature is scaled individually such that the maximal absolute value of each feature after transformation will be 1.0. No shifting/centering is applied.

Parameters:

copy (bool, default=True) – copy=False enables in-place transformation.

Variables:

  • scale (DNDarray of shape (n_features,)) – Per feature relative scaling of the data.

  • max_abs (DNDarray of shape (n_features,)) – Per feature maximum absolute value of the input data.

fit(X: heat.DNDarray) → Self

Fit MaxAbsScaler to input data X: compute the parameters to be used for later scaling.

Parameters:

X (DNDarray of shape (n_datapoints, n_features)) – The data set to which the scaler shall be fitted.

transform(X: heat.DNDarray) → Self | heat.DNDarray

Scale the data with the MaxAbsScaler.

Parameters:

X (DNDarray of shape (n_datapoints, n_features)) – The data set to be scaled.

inverse_transform(Y: heat.DNDarray) → Self | heat.DNDarray

Apply the inverse of :meth:transform, i.e. scale the input data Y back to the original representation.

Parameters:

Y (DNDarray of shape (n_datapoints, n_features)) – The data set to be transformed back.

class RobustScaler(*, with_centering: bool = True, with_scaling: bool = True, quantile_range: Tuple[float, float] = (25.0, 75.0), copy: bool = True, unit_variance: bool = False)

Bases: heat.TransformMixin, heat.BaseEstimator

This scaler transforms the features of a given data set making use of statistics that are robust to outliers: it removes the median and scales the data according to the quantile range (defaults to IQR: Interquartile Range); this routine is similar to sklearn.preprocessing.RobustScaler.

The underyling data set to be scaled must be stored as a 2D-DNDarray of shape (n_datapoints, n_features). Each feature is centered and scaled independently.

Parameters:

  • with_centering (bool, default=True) – If True, data are centered before scaling.

  • with_scaling (bool, default=True) – If True, scale the data to prescribed interquantile range.

  • quantile_range (tuple (q_min, q_max), 0.0 <= q_min < q_max <= 100.0, default=(25.0, 75.0)) – Quantile range used to calculate scale_; default is the so-called the IQR given by q_min=25 and q_max=75.

  • copy (bool, default=True) – copy=False enable in-place transformations.

  • unit_variance (not yet supported.) – raises NotImplementedError

Variables:

  • center (DNDarray of shape (n_features,)) – Feature-wise median value of the given data set.

  • iqr (DNDarray of shape (n_features,)) – length of the interquantile range for each feature.

  • scale (array of floats) – feature-wise inverse of iqr_.

fit(X: heat.DNDarray) → Self

Fit RobustScaler to given data set, i.e. compute the parameters required for transformation.

Parameters:

X (DNDarray of shape (n_datapoints, n_features)) – Data to which the Scaler should be fitted.

transform(X: heat.DNDarray) → Self | heat.DNDarray

Transform given data with RobustScaler

Parameters:

X (DNDarray of shape (n_datapoints, n_features)) – Data set to be transformed.

inverse_transform(Y: heat.DNDarray) → Self | heat.DNDarray

Apply inverse of :meth:transform.

Parameters:

Y (DNDarray of shape (n_datapoints, n_features)) – Data to be back-transformed