keel.Algorithms.Decision_Trees.C45

Class Cut

java.lang.Object

keel.Algorithms.Decision_Trees.C45.Cut

public class Cut
extends java.lang.Object

Class to implement the calculus of the cut point

Since:

JDK 1.5

Version:

0.1

Author:

Written by Cristobal Romero (Universidad de Córdoba) 10/10/2007

Field Summary

Fields

Modifier and Type	Field and Description
protected Classification	classification Classification of class values.
protected int	numSubsets Number of subsets.

Constructor Summary

Constructors

Constructor and Description
Cut(Classification dist) Function to use when no cut is necessary.
Cut(int index, int nObj, double weights) Function to initialize the cut model.

Method Summary

Modifier and Type	Method and Description
int	attributeIndex() Returns the index of the attribute to cut on.
boolean	checkModel() Function to check if generated model is valid.
Classification	classification() Returns the classification created by the model.
void	classify(Dataset trainItemsets) Function to create the cut point.
double	classProbability(int classIndex, Itemset itemset, int subset) Function to compute the probability for itemset.
Dataset[]	cutDataset(Dataset data) Function to cut the dataset in subsets.
static java.lang.String	doubleToString(double value, int afterDecimalPoint) Function to round a double and converts it into String.
static java.lang.String	doubleToString(double value, int width, int afterDecimalPoint) Function to round a double and converts it into String.
double	gainRatioCutCrit(Classification values, double totalnoInst, double numerator) Function to compute the gain ratio.
double	getGainRatio() Returns the gain ratio for the cut.
double	getInfoGain() Returns information gain for the generated cut.
double	infoGainCutCrit(Classification values, double totalNoInst, double oldEnt) Function to compute the information gain.
java.lang.String	label(int index, Dataset data) Function to print label for subset index of itemsets.
java.lang.String	leftSide(Dataset data) Function to print left side of condition.
java.lang.String	leftSideOVO(Dataset data) Function to print left side of condition.
protected double	logFunc(double num) Returns the log2
double	newEntropy(Classification values) Function to compute entropy of classification after cutting.
int	numSubsets() Returns the number of created subsets for the cut.
double	oldEntropy(Classification values) Function to compute entropy of classification before cutting.
void	resetClassification(Dataset data) Function to reset the classification of the model.
java.lang.String	rightSide(int index, Dataset data) Function to print the condition satisfied by itemsets in a subset.
void	setCutPoint(Dataset allItemsets) Function to set the cut point.
double[]	weights(Itemset itemset) Returns weights if itemset is assigned to more than one subset, null otherwise.
int	whichSubset(Itemset itemset) Returns index of subset itemset is assigned to.

Methods inherited from class java.lang.Object

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

Field Detail

classification

protected Classification classification

Classification of class values.

numSubsets

protected int numSubsets

Number of subsets.

Constructor Detail

Cut

public Cut(int index,
           int nObj,
           double weights)

Function to initialize the cut model.

Parameters:

index - The attribute index.

nObj - Minimum number of itemsets.

weights - The weight of all the itemsets.

Cut

public Cut(Classification dist)

Function to use when no cut is necessary.

Parameters:

dist - Distribution of values per class.

Method Detail

classify

public void classify(Dataset trainItemsets)
              throws java.lang.Exception

Function to create the cut point.

Parameters:

trainItemsets - The dataset to classify.

Throws:

java.lang.Exception - If the classification cannot be made.

classProbability

public final double classProbability(int classIndex,
                                     Itemset itemset,
                                     int subset)

Function to compute the probability for itemset.

Parameters:

classIndex - The index of the class.

itemset - The itemset.

subset - The index of the subset.

Returns:

The probability computed.

setCutPoint

public final void setCutPoint(Dataset allItemsets)

Function to set the cut point.

Parameters:

allItemsets - The dataset used for the cut.

cutDataset

public final Dataset[] cutDataset(Dataset data)
                           throws java.lang.Exception

Function to cut the dataset in subsets.

Parameters:

data - The dataset to cut.

Returns:

All the datasets created.

Throws:

java.lang.Exception - If the dataset cannot be cut.

resetClassification

public void resetClassification(Dataset data)
                         throws java.lang.Exception

Function to reset the classification of the model.

Parameters:

data - The new dataset used.

Throws:

java.lang.Exception - If the classification cannot be reset.

weights

public final double[] weights(Itemset itemset)

Returns weights if itemset is assigned to more than one subset, null otherwise.

Parameters:

itemset - The itemset.

Returns:

weights if itemset is assigned to more than one subset, null otherwise

whichSubset

public final int whichSubset(Itemset itemset)

Returns index of subset itemset is assigned to.

Parameters:

itemset - The itemset.

Returns:

index of subset itemset is assigned to.

checkModel

public final boolean checkModel()

Function to check if generated model is valid.

Returns:

True if the model is valid. False otherwise.

classification

public final Classification classification()

Returns the classification created by the model.

Returns:

the classification created by the model

numSubsets

public final int numSubsets()

Returns the number of created subsets for the cut.

Returns:

the number of created subsets for the cut

gainRatioCutCrit

public final double gainRatioCutCrit(Classification values,
                                     double totalnoInst,
                                     double numerator)

Function to compute the gain ratio.

Parameters:

values - The classification used to compute the gain ratio.

totalnoInst - Number of itemsets.

numerator - The information gain.

Returns:

The gain ratio for the classification.

infoGainCutCrit

public final double infoGainCutCrit(Classification values,
                                    double totalNoInst,
                                    double oldEnt)

Function to compute the information gain.

Parameters:

values - The classification used to compute the information gain.

totalNoInst - Number of itemsets.

oldEnt - The value for the entropy before cutting.

Returns:

The information gain.

oldEntropy

public final double oldEntropy(Classification values)

Function to compute entropy of classification before cutting.

Parameters:

values - The classification used to compute the entropy before cutting.

Returns:

The entropy for the classification before cutting.

newEntropy

public final double newEntropy(Classification values)

Function to compute entropy of classification after cutting.

Parameters:

values - The classification used to compute the entropy after cutting.

Returns:

The entropy for the classification after cutting.

logFunc

protected final double logFunc(double num)

Returns the log2

Parameters:

num - The number to compute the log2.

Returns:

the log2 of the number given.

getInfoGain

public final double getInfoGain()

Returns information gain for the generated cut.

Returns:

information gain for the generated cut.

getGainRatio

public final double getGainRatio()

Returns the gain ratio for the cut.

Returns:

the gain ratio for the cut.

leftSide

public final java.lang.String leftSide(Dataset data)

Function to print left side of condition.

Parameters:

data - The dataset.

Returns:

The name of the attribute used in the cut.

leftSideOVO

public final java.lang.String leftSideOVO(Dataset data)

Function to print left side of condition.

Parameters:

data - The dataset.

Returns:

The name of the attribute used in the cut.

rightSide

public final java.lang.String rightSide(int index,
                                        Dataset data)

Function to print the condition satisfied by itemsets in a subset.

Parameters:

index - The index of the value.

data - The dataset.

Returns:

The value for the attribute of the cut.

label

public final java.lang.String label(int index,
                                    Dataset data)

Function to print label for subset index of itemsets.

Parameters:

index - The index of the subset.

data - The dataset.

Returns:

The label created.

attributeIndex

public final int attributeIndex()

Returns the index of the attribute to cut on.

Returns:

the index of the attribute to cut on.

doubleToString

public static java.lang.String doubleToString(double value,
                                              int afterDecimalPoint)

Function to round a double and converts it into String.

Parameters:

value - The value to print.

afterDecimalPoint - Number of decimals positions.

Returns:

The value with the given number of decimals.

doubleToString

public static java.lang.String doubleToString(double value,
                                              int width,
                                              int afterDecimalPoint)

Function to round a double and converts it into String.

Parameters:

value - The value to print.

width - The width that must have the string generated.

afterDecimalPoint - Number of decimals positions.

Returns:

The value with the given number of decimals.