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Class weka.classifiers.j48.C45Split
java.lang.Object
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+----weka.classifiers.j48.ClassifierSplitModel
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+----weka.classifiers.j48.C45Split
- public class C45Split
- extends ClassifierSplitModel
Class implementing a C4.5-type split on an attribute.
- Version:
- $Revision: 1.6 $
- Author:
- Eibe Frank (eibe@cs.waikato.ac.nz)
C45Split(int, int, double)
- Initializes the split model.
attIndex()
- Returns index of attribute for which split was generated.
buildClassifier(Instances)
- Creates a C4.5-type split on the given data.
classProb(int, Instance, int)
- Gets class probability for instance.
codingCost()
- Returns coding cost for split (used in rule learner).
gainRatio()
- Returns (C4.5-type) gain ratio for the generated split.
infoGain()
- Returns (C4.5-type) information gain for the generated split.
leftSide(Instances)
- Prints left side of condition..
minsAndMaxs(Instances, double[][], int)
- Returns the minsAndMaxs of the index.th subset.
resetDistribution(Instances)
- Sets distribution associated with model.
rightSide(int, Instances)
- Prints the condition satisfied by instances in a subset.
setSplitPoint(Instances)
- Sets split point to greatest value in given data smaller or equal to
old split point.
sourceExpression(int, Instances)
- Returns a string containing java source code equivalent to the test
made at this node.
weights(Instance)
- Returns weights if instance is assigned to more than one subset.
whichSubset(Instance)
- Returns index of subset instance is assigned to.
C45Split
public C45Split(int attIndex,
int minNoObj,
double sumOfWeights)
Initializes the split model.
buildClassifier
public void buildClassifier(Instances trainInstances) throws java.lang.Exception
Creates a C4.5-type split on the given data. Assumes that none of
the class values is missing.
- Throws:
- java.lang.Exception - if something goes wrong
- Overrides:
- buildClassifier in class ClassifierSplitModel
attIndex
public final int attIndex()
Returns index of attribute for which split was generated.
classProb
public final double classProb(int classIndex,
Instance instance,
int theSubset) throws java.lang.Exception
Gets class probability for instance.
- Throws:
- java.lang.Exception - if something goes wrong
- Overrides:
- classProb in class ClassifierSplitModel
codingCost
public final double codingCost()
Returns coding cost for split (used in rule learner).
- Overrides:
- codingCost in class ClassifierSplitModel
gainRatio
public final double gainRatio()
Returns (C4.5-type) gain ratio for the generated split.
infoGain
public final double infoGain()
Returns (C4.5-type) information gain for the generated split.
leftSide
public final java.lang.String leftSide(Instances data)
Prints left side of condition..
- Parameters:
data
- training set.
- Overrides:
- leftSide in class ClassifierSplitModel
rightSide
public final java.lang.String rightSide(int index,
Instances data)
Prints the condition satisfied by instances in a subset.
- Parameters:
index
- of subset
data
- training set.
- Overrides:
- rightSide in class ClassifierSplitModel
sourceExpression
public final java.lang.String sourceExpression(int index,
Instances data)
Returns a string containing java source code equivalent to the test
made at this node. The instance being tested is called "i".
- Parameters:
index
- index of the nominal value tested
data
- the data containing instance structure info
- Returns:
- a value of type 'String'
- Overrides:
- sourceExpression in class ClassifierSplitModel
setSplitPoint
public final void setSplitPoint(Instances allInstances)
Sets split point to greatest value in given data smaller or equal to
old split point.
(C4.5 does this for some strange reason).
minsAndMaxs
public final double[][] minsAndMaxs(Instances data,
double minsAndMaxs[][],
int index)
Returns the minsAndMaxs of the index.th subset.
resetDistribution
public void resetDistribution(Instances data) throws java.lang.Exception
Sets distribution associated with model.
- Overrides:
- resetDistribution in class ClassifierSplitModel
weights
public final double[] weights(Instance instance)
Returns weights if instance is assigned to more than one subset.
Returns null if instance is only assigned to one subset.
- Overrides:
- weights in class ClassifierSplitModel
whichSubset
public final int whichSubset(Instance instance) throws java.lang.Exception
Returns index of subset instance is assigned to.
Returns -1 if instance is assigned to more than one subset.
- Throws:
- java.lang.Exception - if something goes wrong
- Overrides:
- whichSubset in class ClassifierSplitModel
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