SplitMetric

java.lang.Object
- weka.classifiers.trees.ht.SplitMetric

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

GiniSplitMetric, InfoGainSplitMetric
```
public abstract class SplitMetric
extends java.lang.Object
implements java.io.Serializable
```
Base class for split metrics

Version:

$Revision: 9720 $

Author:

Richard Kirkby (rkirkby@cs.waikato.ac.nz), Mark Hall (mhall{[at]}pentaho{[dot]}com)

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor Description

SplitMetric()

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract double`	`evaluateSplit(java.util.Map<java.lang.String,WeightMass> preDist, java.util.List<java.util.Map<java.lang.String,WeightMass>> postDist)`	Evaluate the merit of a split
`abstract double`	`getMetricRange(java.util.Map<java.lang.String,WeightMass> preDist)`	Get the range of the splitting metric
`static double`	`sum(java.util.Map<java.lang.String,WeightMass> dist)`	Utility method to return the sum of instance weight in a distribution

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SplitMetric
```
public SplitMetric()
```
- Method Detail
  - sum
```
public static double sum(java.util.Map<java.lang.String,WeightMass> dist)
```
    Utility method to return the sum of instance weight in a distribution
    
    Parameters:
    
    dist - the distribution
    
    Returns:
    
    the sum of the weights contained in a distribution
  - evaluateSplit
```
public abstract double evaluateSplit(java.util.Map<java.lang.String,WeightMass> preDist,
                                     java.util.List<java.util.Map<java.lang.String,WeightMass>> postDist)
```
    Evaluate the merit of a split
    
    Parameters:
    
    preDist - the class distribution before the split
    
    postDist - the class distributions after the split
    
    Returns:
    
    the merit of the split
  - getMetricRange
```
public abstract double getMetricRange(java.util.Map<java.lang.String,WeightMass> preDist)
```
    Get the range of the splitting metric
    
    Parameters:
    
    preDist - the pre-split class distribution
    
    Returns:
    
    the range of the splitting metric