RandomSubSpace

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## weka.classifiers.meta
Class RandomSubSpace

    java.lang.Object
      weka.classifiers.Classifier
          weka.classifiers.SingleClassifierEnhancer
              weka.classifiers.IteratedSingleClassifierEnhancer
                  weka.classifiers.RandomizableIteratedSingleClassifierEnhancer
                      weka.classifiers.meta.RandomSubSpace

All Implemented Interfaces:
  java.io.Serializable, java.lang.Cloneable, CapabilitiesHandler, OptionHandler, Randomizable, RevisionHandler, TechnicalInformationHandler, WeightedInstancesHandler

    public class RandomSubSpace

extends RandomizableIteratedSingleClassifierEnhancer
implements WeightedInstancesHandler, TechnicalInformationHandler

This method constructs a decision tree based classifier that maintains highest accuracy on training data and improves on generalization accuracy as it grows in complexity. The classifier consists of multiple trees constructed systematically by pseudorandomly selecting subsets of components of the feature vector, that is, trees constructed in randomly chosen subspaces.
For more information, see
Tin Kam Ho (1998). The Random Subspace Method for Constructing Decision Forests. IEEE Transactions on Pattern Analysis and Machine Intelligence. 20(8):832-844. URL http://citeseer.ist.psu.edu/ho98random.html.

BibTeX:

     @article{Ho1998,
        author = {Tin Kam Ho},
        journal = {IEEE Transactions on Pattern Analysis and Machine Intelligence},
        number = {8},
        pages = {832-844},
        title = {The Random Subspace Method for Constructing Decision Forests},
        volume = {20},
        year = {1998},
        ISSN = {0162-8828},
        URL = {http://citeseer.ist.psu.edu/ho98random.html}
     }

Valid options are:

     -P
      Size of each subspace:
       < 1: percentage of the number of attributes
       >=1: absolute number of attributes

     -S <num>
      Random number seed.
      (default 1)

     -I <num>
      Number of iterations.
      (default 10)

     -D
      If set, classifier is run in debug mode and
      may output additional info to the console

     -W
      Full name of base classifier.
      (default: weka.classifiers.trees.REPTree)

     Options specific to classifier weka.classifiers.trees.REPTree:

     -M <minimum number of instances>
      Set minimum number of instances per leaf (default 2).

     -V <minimum variance for split>
      Set minimum numeric class variance proportion
      of train variance for split (default 1e-3).

     -N <number of folds>
      Number of folds for reduced error pruning (default 3).

     -S <seed>
      Seed for random data shuffling (default 1).

     -P
      No pruning.

     -L
      Maximum tree depth (default -1, no maximum)

Options after -- are passed to the designated classifier.

Version:
  $Revision: 1.4 $
Author:
  Bernhard Pfahringer (bernhard@cs.waikato.ac.nz), Peter Reutemann (fracpete@cs.waikato.ac.nz)
See Also:
  Serialized Form

Constructor Summary
`RandomSubSpace()` Constructor.

Method Summary
`void` | `buildClassifier(Instances data)` builds the classifier.
`double[]` | `distributionForInstance(Instance instance)` Calculates the class membership probabilities for the given test instance.
`java.lang.String[]` | `getOptions()` Gets the current settings of the Classifier.
`java.lang.String` | `getRevision()` Returns the revision string.
`double` | `getSubSpaceSize()` Gets the size of each subSpace, as a percentage of the training set size.
`TechnicalInformation` | `getTechnicalInformation()` Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.
`java.lang.String` | `globalInfo()` Returns a string describing classifier
`java.util.Enumeration` | `listOptions()` Returns an enumeration describing the available options.
`static void` | `main(java.lang.String[] args)` Main method for testing this class.
`void` | `setOptions(java.lang.String[] options)` Parses a given list of options.
`void` | `setSubSpaceSize(double value)` Sets the size of each subSpace, as a percentage of the training set size.
`java.lang.String` | `subSpaceSizeTipText()` Returns the tip text for this property
`java.lang.String` | `toString()` Returns description of the bagged classifier.

Methods inherited from class weka.classifiers.RandomizableIteratedSingleClassifierEnhancer
`getSeed, seedTipText, setSeed`

Methods inherited from class weka.classifiers.IteratedSingleClassifierEnhancer
`getNumIterations, numIterationsTipText, setNumIterations`

Methods inherited from class weka.classifiers.SingleClassifierEnhancer
`classifierTipText, getCapabilities, getClassifier, setClassifier`

Methods inherited from class weka.classifiers.Classifier
`classifyInstance, debugTipText, forName, getDebug, makeCopies, makeCopy, setDebug`

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

Constructor Detail

### RandomSubSpace

    public RandomSubSpace()

  Constructor.

Method Detail

### globalInfo

    public java.lang.String globalInfo()

  Returns a string describing classifier

  Returns:
    a description suitable for displaying in the explorer/experimenter gui

### getTechnicalInformation

    public TechnicalInformation getTechnicalInformation()

  Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.

  Specified by:
    `getTechnicalInformation` in interface `TechnicalInformationHandler`
  Returns:
    the technical information about this class

### listOptions

    public java.util.Enumeration listOptions()

  Returns an enumeration describing the available options.

  Specified by:
    `listOptions` in interface `OptionHandler`
  Overrides:
    `listOptions` in class `RandomizableIteratedSingleClassifierEnhancer`
  Returns:
    an enumeration of all the available options.

### setOptions

    public void setOptions(java.lang.String[] options)
                    throws java.lang.Exception

  Parses a given list of options.

  Valid options are:

       -P
        Size of each subspace:
         < 1: percentage of the number of attributes
         >=1: absolute number of attributes

       -S <num>
        Random number seed.
        (default 1)

       -I <num>
        Number of iterations.
        (default 10)

       -D
        If set, classifier is run in debug mode and
        may output additional info to the console

       -W
        Full name of base classifier.
        (default: weka.classifiers.trees.REPTree)

       Options specific to classifier weka.classifiers.trees.REPTree:

       -M <minimum number of instances>
        Set minimum number of instances per leaf (default 2).

       -V <minimum variance for split>
        Set minimum numeric class variance proportion
        of train variance for split (default 1e-3).

       -N <number of folds>
        Number of folds for reduced error pruning (default 3).

       -S <seed>
        Seed for random data shuffling (default 1).

       -P
        No pruning.

       -L
        Maximum tree depth (default -1, no maximum)

  Options after -- are passed to the designated classifier.

  Specified by:
    `setOptions` in interface `OptionHandler`
  Overrides:
    `setOptions` in class `RandomizableIteratedSingleClassifierEnhancer`
  Parameters:
    `options` - the list of options as an array of strings
  Throws:
    `java.lang.Exception` - if an option is not supported

### getOptions

    public java.lang.String[] getOptions()

  Gets the current settings of the Classifier.

  Specified by:
    `getOptions` in interface `OptionHandler`
  Overrides:
    `getOptions` in class `RandomizableIteratedSingleClassifierEnhancer`
  Returns:
    an array of strings suitable for passing to setOptions

### subSpaceSizeTipText

    public java.lang.String subSpaceSizeTipText()

  Returns the tip text for this property

  Returns:
    tip text for this property suitable for displaying in the explorer/experimenter gui

### getSubSpaceSize

    public double getSubSpaceSize()

  Gets the size of each subSpace, as a percentage of the training set size.

  Returns:
    the subSpace size, as a percentage.

### setSubSpaceSize

    public void setSubSpaceSize(double value)

  Sets the size of each subSpace, as a percentage of the training set size.

  Parameters:
    `value` - the subSpace size, as a percentage.

### buildClassifier

    public void buildClassifier(Instances data)
                         throws java.lang.Exception

  builds the classifier.

  Overrides:
    `buildClassifier` in class `IteratedSingleClassifierEnhancer`
  Parameters:
    `data` - the training data to be used for generating the classifier.
  Throws:
    `java.lang.Exception` - if the classifier could not be built successfully

### distributionForInstance

    public double[] distributionForInstance(Instance instance)
                                     throws java.lang.Exception

  Calculates the class membership probabilities for the given test instance.

  Overrides:
    `distributionForInstance` in class `Classifier`
  Parameters:
    `instance` - the instance to be classified
  Returns:
    preedicted class probability distribution
  Throws:
    `java.lang.Exception` - if distribution can't be computed successfully

### toString

    public java.lang.String toString()

  Returns description of the bagged classifier.

  Overrides:
    `toString` in class `java.lang.Object`
  Returns:
    description of the bagged classifier as a string

### getRevision

    public java.lang.String getRevision()

  Returns the revision string.

  Specified by:
    `getRevision` in interface `RevisionHandler`
  Returns:
    the revision

### main

    public static void main(java.lang.String[] args)

  Main method for testing this class.

  Parameters:
    `args` - the options

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