smile.feature

Class Standardizer

java.lang.Object

smile.feature.Standardizer

All Implemented Interfaces:

java.io.Serializable, FeatureTransform

Direct Known Subclasses:

RobustStandardizer

public class Standardizer
extends java.lang.Object
implements FeatureTransform

Standardizes numeric feature to 0 mean and unit variance. Standardization makes an assumption that the data follows a Gaussian distribution and are also not robust when outliers present. A robust alternative is to subtract the median and divide by the IQR by RobustStandardizer.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Standardizer(smile.data.type.StructType schema, double[] mu, double[] std) Constructor.

Method Summary

Modifier and Type	Method and Description
static Standardizer	fit(smile.data.DataFrame data) Learns transformation parameters from a dataset.
static Standardizer	fit(double[][] data) Learns transformation parameters from a dataset.
java.lang.String	toString()
smile.data.DataFrame	transform(smile.data.DataFrame data) Transform a data frame.
double[]	transform(double[] x) Transform a feature vector.
smile.data.Tuple	transform(smile.data.Tuple x) Transform a feature vector.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface smile.feature.FeatureTransform

transform

Constructor Detail

Standardizer

public Standardizer(smile.data.type.StructType schema,
                    double[] mu,
                    double[] std)

Constructor.

Parameters:

schema - the schema of data.

mu - mean.

std - standard deviation.

Method Detail

fit

public static Standardizer fit(smile.data.DataFrame data)

Learns transformation parameters from a dataset.

Parameters:

data - The training data.

fit

public static Standardizer fit(double[][] data)

Learns transformation parameters from a dataset.

Parameters:

data - The training data.

transform

public double[] transform(double[] x)

Description copied from interface: FeatureTransform

Transform a feature vector.

Specified by:

transform in interface FeatureTransform

Parameters:

x - a feature vector.

Returns:

the transformed feature value.

transform

public smile.data.Tuple transform(smile.data.Tuple x)

Description copied from interface: FeatureTransform

Transform a feature vector.

Specified by:

transform in interface FeatureTransform

Parameters:

x - a feature vector.

Returns:

the transformed feature value.

transform

public smile.data.DataFrame transform(smile.data.DataFrame data)

Description copied from interface: FeatureTransform

Transform a data frame.

Specified by:

transform in interface FeatureTransform

Parameters:

data - a data frame.

Returns:

the transformed data frame.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object