Package smile.feature.selection

Class SignalNoiseRatio

java.lang.Object

smile.feature.selection.SignalNoiseRatio

All Implemented Interfaces:

Comparable<SignalNoiseRatio>

public class SignalNoiseRatio
extends Object
implements Comparable<SignalNoiseRatio>

The signal-to-noise (S2N) metric ratio is a univariate feature ranking metric, which can be used as a feature selection criterion for binary classification problems. S2N is defined as |μ₁ - μ₂| / (σ₁ + σ₂), where μ₁ and μ₂ are the mean value of the variable in classes 1 and 2, respectively, and σ₁ and σ₂ are the standard deviations of the variable in classes 1 and 2, respectively. Clearly, features with larger S2N ratios are better for classification.

References

1. M. Shipp, et al. Diffuse large B-cell lymphoma outcome prediction by gene-expression profiling and supervised machine learning. Nature Medicine, 2002.

Field Summary

Fields

Modifier and Type	Field	Description
final String	feature	The feature name.
final double	s2n	Signal noise ratio.

Constructor Summary

Constructors

Constructor	Description
SignalNoiseRatio(String feature, double s2n)	Constructor.

Method Summary

Modifier and Type	Method	Description
int	compareTo(SignalNoiseRatio other)
static SignalNoiseRatio[]	fit(DataFrame data, String clazz)	Calculates the signal noise ratio of numeric variables.
String	toString()

Methods inherited from class java.lang.Object

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

Field Details

feature

public final String feature

The feature name.

s2n

public final double s2n

Signal noise ratio.

Constructor Details

SignalNoiseRatio

public SignalNoiseRatio(String feature,
 double s2n)

Constructor.

Parameters:

feature - The feature name.

s2n - Signal noise ratio.

Method Details

compareTo

public int compareTo(SignalNoiseRatio other)

Specified by:

compareTo in interface Comparable<SignalNoiseRatio>

toString

public String toString()

Overrides:

toString in class Object

fit

public static SignalNoiseRatio[] fit(DataFrame data,
 String clazz)

Calculates the signal noise ratio of numeric variables.

Parameters:

data - the data frame of the explanatory and response variables.

clazz - the column name of binary class labels.

Returns:

the signal noise ratio.