fr.lip6.jkernelmachines.evaluation

Class NFoldCrossValidation<T>

java.lang.Object

fr.lip6.jkernelmachines.evaluation.NFoldCrossValidation<T>

All Implemented Interfaces:

BalancedCrossValidation, CrossValidation, MultipleEvaluatorCrossValidation<T>

public class NFoldCrossValidation<T>
extends java.lang.Object
implements CrossValidation, BalancedCrossValidation, MultipleEvaluatorCrossValidation<T>

Class for performing N-Fold Cross-validation.

The list of samples used is taken in order. Let us consider 10 folds. For the first fold, the first 10% are used for testing, and the remaining 90% are used for training. For the second fold, the second 10% are used for testing, and the remaining for training, and so on. Warning, no randomization is performed on the list, so be careful it is not in the order of the classes which would bias the learning. This CV is balanced by default

Author:

picard

Constructor Summary

Constructors

Constructor and Description
NFoldCrossValidation(int n, Classifier<T> cls, java.util.List<TrainingSample<T>> l, Evaluator<T> eval) Default constructor with number of folds, classifier, full samples list and evaluation metric.

Method Summary

Modifier and Type	Method and Description
void	addEvaluator(java.lang.String name, Evaluator<T> e) Register a new evaluator to this corssvalidation
double	getAverageScore() Tells the average score of the test
double	getAverageScore(java.lang.String name) Tells the average score of the test for the given evaluator
double[]	getScores() Tells the scores of the tests, in order of evaluation
double[]	getScores(java.lang.String name) Tells the scores of the tests, in order of evaluation for the given evaluator
double	getStdDevScore() Tells the standard deviation of the test
double	getStdDevScore(java.lang.String name) Tells the standard deviation of the test for the given evaluator
boolean	isBalanced() Returns true if the splits are balanced between positive and negative
void	removeEvaluator(java.lang.String name) unregister the evaluator by its name
void	run() perform learning and evaluations
void	setBalanced(boolean balanced) Set class balancing strategy when computing the splits

Methods inherited from class java.lang.Object

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

Constructor Detail

NFoldCrossValidation

public NFoldCrossValidation(int n,
                            Classifier<T> cls,
                            java.util.List<TrainingSample<T>> l,
                            Evaluator<T> eval)

Default constructor with number of folds, classifier, full samples list and evaluation metric.

Parameters:

n - the number of folds

cls - the classifier to evaluate

l - the full list of sample

eval - the evaluation metric to compute on each fold

Method Detail

run

public void run()

Description copied from interface: CrossValidation

perform learning and evaluations

Specified by:

run in interface CrossValidation

getAverageScore

public double getAverageScore()

Description copied from interface: CrossValidation

Tells the average score of the test

Specified by:

getAverageScore in interface CrossValidation

Returns:

the average score

getStdDevScore

public double getStdDevScore()

Description copied from interface: CrossValidation

Tells the standard deviation of the test

Specified by:

getStdDevScore in interface CrossValidation

Returns:

the standard deviation

getScores

public double[] getScores()

Description copied from interface: CrossValidation

Tells the scores of the tests, in order of evaluation

Specified by:

getScores in interface CrossValidation

Returns:

an array with the scores in order

isBalanced

public boolean isBalanced()

Returns true if the splits are balanced between positive and negative

Specified by:

isBalanced in interface BalancedCrossValidation

Returns:

setBalanced

public void setBalanced(boolean balanced)

Set class balancing strategy when computing the splits

Specified by:

setBalanced in interface BalancedCrossValidation

Parameters:

balanced - true if enables balancing

addEvaluator

public void addEvaluator(java.lang.String name,
                         Evaluator<T> e)

Description copied from interface: MultipleEvaluatorCrossValidation

Register a new evaluator to this corssvalidation

Specified by:

addEvaluator in interface MultipleEvaluatorCrossValidation<T>

Parameters:

name - a string associated with this evaluator

e - the evaluator

removeEvaluator

public void removeEvaluator(java.lang.String name)

Description copied from interface: MultipleEvaluatorCrossValidation

unregister the evaluator by its name

Specified by:

removeEvaluator in interface MultipleEvaluatorCrossValidation<T>

Parameters:

name - the name of the evaluator

getAverageScore

public double getAverageScore(java.lang.String name)

Description copied from interface: MultipleEvaluatorCrossValidation

Tells the average score of the test for the given evaluator

Specified by:

getAverageScore in interface MultipleEvaluatorCrossValidation<T>

Parameters:

name - name of the evaluator

Returns:

the average score

getStdDevScore

public double getStdDevScore(java.lang.String name)

Description copied from interface: MultipleEvaluatorCrossValidation

Tells the standard deviation of the test for the given evaluator

Specified by:

getStdDevScore in interface MultipleEvaluatorCrossValidation<T>

Parameters:

name - name of the evaluator

Returns:

the standard deviation

getScores

public double[] getScores(java.lang.String name)

Description copied from interface: MultipleEvaluatorCrossValidation

Tells the scores of the tests, in order of evaluation for the given evaluator

Specified by:

getScores in interface MultipleEvaluatorCrossValidation<T>

Parameters:

name - of the evaluator

Returns:

an array with the scores in order