Package smile.feature.selection

Record Class SumSquaresRatio

java.lang.Object

java.lang.Record

smile.feature.selection.SumSquaresRatio

Record Components:

feature - The feature name.

ratio - Sum squares ratio.

All Implemented Interfaces:

Comparable<SumSquaresRatio>

public record SumSquaresRatio(String feature, double ratio)
extends Record
implements Comparable<SumSquaresRatio>

The ratio of between-groups to within-groups sum of squares is a univariate feature ranking metric, which can be used as a feature selection criterion for multi-class classification problems. For each variable j, this ratio is BSS(j) / WSS(j) = ΣI(y_i = k)(x_kj - x_·j)² / ΣI(y_i = k)(x_ij - x_kj)²; where x_·j denotes the average of variable j across all samples, x_kj denotes the average of variable j across samples belonging to class k, and x_ij is the value of variable j of sample i. Clearly, features with larger sum squares ratios are better for classification.

References

1. S. Dudoit, J. Fridlyand and T. Speed. Comparison of discrimination methods for the classification of tumors using gene expression data. J Am Stat Assoc, 97:77-87, 2002.

Constructor Summary

Constructors

Constructor	Description
SumSquaresRatio(String feature, double ratio)	Creates an instance of a SumSquaresRatio record class.

Method Summary

Modifier and Type	Method	Description
int	compareTo(SumSquaresRatio other)
final boolean	equals(Object o)	Indicates whether some other object is "equal to" this one.
String	feature()	Returns the value of the feature record component.
static SumSquaresRatio[]	fit(DataFrame data, String clazz)	Calculates the sum squares ratio of numeric variables.
final int	hashCode()	Returns a hash code value for this object.
double	ratio()	Returns the value of the ratio record component.
String	toString()	Returns a string representation of this record class.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

SumSquaresRatio

public SumSquaresRatio(String feature,
 double ratio)

Creates an instance of a SumSquaresRatio record class.

Parameters:

feature - the value for the feature record component

ratio - the value for the ratio record component

Method Details

compareTo

public int compareTo(SumSquaresRatio other)

Specified by:

compareTo in interface Comparable<SumSquaresRatio>

toString

public String toString()

Returns a string representation of this record class. The representation contains the name of the class, followed by the name and value of each of the record components.

Specified by:

toString in class Record

Returns:

a string representation of this object

fit

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

Calculates the sum squares ratio of numeric variables.

Parameters:

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

clazz - the column name of class labels.

Returns:

the sum squares ratio.

hashCode

public final int hashCode()

Returns a hash code value for this object. The value is derived from the hash code of each of the record components.

Specified by:

hashCode in class Record

Returns:

a hash code value for this object

equals

public final boolean equals(Object o)

Indicates whether some other object is "equal to" this one. The objects are equal if the other object is of the same class and if all the record components are equal. Reference components are compared with Objects::equals(Object,Object); primitive components are compared with '=='.

Specified by:

equals in class Record

Parameters:

o - the object with which to compare

Returns:

true if this object is the same as the o argument; false otherwise.

feature

public String feature()

Returns the value of the feature record component.

Returns:

the value of the feature record component

ratio

public double ratio()

Returns the value of the ratio record component.

Returns:

the value of the ratio record component