weka.classifiers.rules

## Class JRip

- java.lang.Object
- - weka.classifiers.AbstractClassifier
  - - weka.classifiers.rules.JRip

- All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, Classifier, AdditionalMeasureProducer, CapabilitiesHandler, CapabilitiesIgnorer, OptionHandler, RevisionHandler, TechnicalInformationHandler, WeightedInstancesHandler

      public class JRip
      extends AbstractClassifier
      implements AdditionalMeasureProducer, WeightedInstancesHandler, TechnicalInformationHandler

  This class implements a propositional rule learner, Repeated Incremental Pruning to Produce Error Reduction (RIPPER), which was proposed by William W. Cohen as an optimized version of IREP.
  The algorithm is briefly described as follows:
  Initialize RS = {}, and for each class from the less prevalent one to the more frequent one, DO:
  1. Building stage:
  Repeat 1.1 and 1.2 until the descrition length (DL) of the ruleset and examples is 64 bits greater than the smallest DL met so far, or there are no positive examples, or the error rate >= 50%.
  1.1. Grow phase:
  Grow one rule by greedily adding antecedents (or conditions) to the rule until the rule is perfect (i.e. 100% accurate). The procedure tries every possible value of each attribute and selects the condition with highest information gain: p(log(p/t)-log(P/T)).
  1.2. Prune phase:
  Incrementally prune each rule and allow the pruning of any final sequences of the antecedents;The pruning metric is (p-n)/(p+n) -- but it's actually 2p/(p+n) -1, so in this implementation we simply use p/(p+n) (actually (p+1)/(p+n+2), thus if p+n is 0, it's 0.5).
  2. Optimization stage:
  after generating the initial ruleset {Ri}, generate and prune two variants of each rule Ri from randomized data using procedure 1.1 and 1.2. But one variant is generated from an empty rule while the other is generated by greedily adding antecedents to the original rule. Moreover, the pruning metric used here is (TP+TN)/(P+N).Then the smallest possible DL for each variant and the original rule is computed. The variant with the minimal DL is selected as the final representative of Ri in the ruleset.After all the rules in {Ri} have been examined and if there are still residual positives, more rules are generated based on the residual positives using Building Stage again.
  3. Delete the rules from the ruleset that would increase the DL of the whole ruleset if it were in it. and add resultant ruleset to RS.
  ENDDO
  Note that there seem to be 2 bugs in the original ripper program that would affect the ruleset size and accuracy slightly. This implementation avoids these bugs and thus is a little bit different from Cohen's original implementation. Even after fixing the bugs, since the order of classes with the same frequency is not defined in ripper, there still seems to be some trivial difference between this implementation and the original ripper, especially for audiology data in UCI repository, where there are lots of classes of few instances.
  Details please see:
  William W. Cohen: Fast Effective Rule Induction. In: Twelfth International Conference on Machine Learning, 115-123, 1995.
  PS. We have compared this implementation with the original ripper implementation in aspects of accuracy, ruleset size and running time on both artificial data "ab+bcd+defg" and UCI datasets. In all these aspects it seems to be quite comparable to the original ripper implementation. However, we didn't consider memory consumption optimization in this implementation.

  BibTeX:

       @inproceedings{Cohen1995,
          author = {William W. Cohen},
          booktitle = {Twelfth International Conference on Machine Learning},
          pages = {115-123},
          publisher = {Morgan Kaufmann},
          title = {Fast Effective Rule Induction},
          year = {1995}
       }

  Valid options are:

       -F <number of folds>
        Set number of folds for REP
        One fold is used as pruning set.
        (default 3)

       -N <min. weights>
        Set the minimal weights of instances
        within a split.
        (default 2.0)

       -O <number of runs>
        Set the number of runs of
        optimizations. (Default: 2)

       -D
        Set whether turn on the
        debug mode (Default: false)

       -S <seed>
        The seed of randomization
        (Default: 1)

       -E
        Whether NOT check the error rate>=0.5
        in stopping criteria  (default: check)

       -P
        Whether NOT use pruning
        (default: use pruning)

  Version:
    $Revision: 10153 $
  Author:
    Xin Xu (xx5@cs.waikato.ac.nz), Eibe Frank (eibe@cs.waikato.ac.nz)
  See Also:
    Serialized Form

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `class` | `JRip.Antd` The single antecedent in the rule, which is composed of an attribute and the corresponding value.
    `class` | `JRip.NominalAntd` The antecedent with nominal attribute
    `class` | `JRip.NumericAntd` The antecedent with numeric attribute
    `class` | `JRip.RipperRule` This class implements a single rule that predicts specified class.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `JRip()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `buildClassifier(Instances instances)` Builds Ripper in the order of class frequencies.
    `java.lang.String` | `checkErrorRateTipText()` Returns the tip text for this property
    `java.lang.String` | `debugTipText()` Returns the tip text for this property
    `double[]` | `distributionForInstance(Instance datum)` Classify the test instance with the rule learner and provide the class distributions
    `java.util.Enumeration<java.lang.String>` | `enumerateMeasures()` Returns an enumeration of the additional measure names
    `java.lang.String` | `foldsTipText()` Returns the tip text for this property
    `Capabilities` | `getCapabilities()` Returns default capabilities of the classifier.
    `boolean` | `getCheckErrorRate()` Gets whether to check for error rate is in stopping criterion
    `boolean` | `getDebug()` Gets whether debug information is output to the console
    `int` | `getFolds()` Gets the number of folds
    `double` | `getMeasure(java.lang.String additionalMeasureName)` Returns the value of the named measure
    `double` | `getMinNo()` Gets the minimum total weight of the instances in a rule
    `int` | `getOptimizations()` Gets the the number of optimization runs
    `java.lang.String[]` | `getOptions()` Gets the current settings of the Classifier.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `java.util.ArrayList<Rule>` | `getRuleset()` Get the ruleset generated by Ripper
    `RuleStats` | `getRuleStats(int pos)` Get the statistics of the ruleset in the given position
    `long` | `getSeed()` Gets the current seed value to use in randomizing the data
    `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.
    `boolean` | `getUsePruning()` Gets whether pruning is performed
    `java.lang.String` | `globalInfo()` Returns a string describing classifier
    `java.util.Enumeration<Option>` | `listOptions()` Returns an enumeration describing the available options Valid options are:
    `static void` | `main(java.lang.String[] args)` Main method.
    `java.lang.String` | `minNoTipText()` Returns the tip text for this property
    `java.lang.String` | `optimizationsTipText()` Returns the tip text for this property
    `java.lang.String` | `seedTipText()` Returns the tip text for this property
    `void` | `setCheckErrorRate(boolean d)` Sets whether to check for error rate is in stopping criterion
    `void` | `setDebug(boolean d)` Sets whether debug information is output to the console
    `void` | `setFolds(int fold)` Sets the number of folds to use
    `void` | `setMinNo(double m)` Sets the minimum total weight of the instances in a rule
    `void` | `setOptimizations(int run)` Sets the number of optimization runs
    `void` | `setOptions(java.lang.String[] options)` Parses a given list of options.
    `void` | `setSeed(long s)` Sets the seed value to use in randomizing the data
    `void` | `setUsePruning(boolean d)` Sets whether pruning is performed
    `java.lang.String` | `toString()` Prints the all the rules of the rule learner.
    `java.lang.String` | `usePruningTipText()` Returns the tip text for this property

    - ### Methods inherited from class weka.classifiers.AbstractClassifier

      `classifyInstance, doNotCheckCapabilitiesTipText, forName, getDoNotCheckCapabilities, makeCopies, makeCopy, runClassifier, setDoNotCheckCapabilities`

    - ### Methods inherited from class java.lang.Object

      `equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### JRip

          public JRip()

  - ### 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<Option> listOptions()

      Returns an enumeration describing the available options Valid options are:

      -F number
      The number of folds for reduced error pruning. One fold is used as the pruning set. (Default: 3)

      -N number
      The minimal weights of instances within a split. (Default: 2)

      -O number
      Set the number of runs of optimizations. (Default: 2)

      -D
      Whether turn on the debug mode -S number
      The seed of randomization used in Ripper.(Default: 1)

      -E
      Whether NOT check the error rate >= 0.5 in stopping criteria. (default: check)

      -P
      Whether NOT use pruning. (default: use pruning)

      Specified by:
        `listOptions` in interface `OptionHandler`
      Overrides:
        `listOptions` in class `AbstractClassifier`
      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:

           -F <number of folds>
            Set number of folds for REP
            One fold is used as pruning set.
            (default 3)

           -N <min. weights>
            Set the minimal weights of instances
            within a split.
            (default 2.0)

           -O <number of runs>
            Set the number of runs of
            optimizations. (Default: 2)

           -D
            Set whether turn on the
            debug mode (Default: false)

           -S <seed>
            The seed of randomization
            (Default: 1)

           -E
            Whether NOT check the error rate>=0.5
            in stopping criteria  (default: check)

           -P
            Whether NOT use pruning
            (default: use pruning)

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

    - #### enumerateMeasures

          public java.util.Enumeration<java.lang.String> enumerateMeasures()

      Returns an enumeration of the additional measure names
      Specified by:
        `enumerateMeasures` in interface `AdditionalMeasureProducer`
      Returns:
        an enumeration of the measure names

    - #### getMeasure

          public double getMeasure(java.lang.String additionalMeasureName)

      Returns the value of the named measure
      Specified by:
        `getMeasure` in interface `AdditionalMeasureProducer`
      Parameters:
        `additionalMeasureName` - the name of the measure to query for its value
      Returns:
        the value of the named measure
      Throws:
        `java.lang.IllegalArgumentException` - if the named measure is not supported

    - #### foldsTipText

          public java.lang.String foldsTipText()

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

    - #### setFolds

          public void setFolds(int fold)

      Sets the number of folds to use
      Parameters:
        `fold` - the number of folds

    - #### getFolds

          public int getFolds()

      Gets the number of folds
      Returns:
        the number of folds

    - #### minNoTipText

          public java.lang.String minNoTipText()

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

    - #### setMinNo

          public void setMinNo(double m)

      Sets the minimum total weight of the instances in a rule
      Parameters:
        `m` - the minimum total weight of the instances in a rule

    - #### getMinNo

          public double getMinNo()

      Gets the minimum total weight of the instances in a rule
      Returns:
        the minimum total weight of the instances in a rule

    - #### seedTipText

          public java.lang.String seedTipText()

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

    - #### setSeed

          public void setSeed(long s)

      Sets the seed value to use in randomizing the data
      Parameters:
        `s` - the new seed value

    - #### getSeed

          public long getSeed()

      Gets the current seed value to use in randomizing the data
      Returns:
        the seed value

    - #### optimizationsTipText

          public java.lang.String optimizationsTipText()

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

    - #### setOptimizations

          public void setOptimizations(int run)

      Sets the number of optimization runs
      Parameters:
        `run` - the number of optimization runs

    - #### getOptimizations

          public int getOptimizations()

      Gets the the number of optimization runs
      Returns:
        the number of optimization runs

    - #### debugTipText

          public java.lang.String debugTipText()

      Returns the tip text for this property
      Overrides:
        `debugTipText` in class `AbstractClassifier`
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### setDebug

          public void setDebug(boolean d)

      Sets whether debug information is output to the console
      Overrides:
        `setDebug` in class `AbstractClassifier`
      Parameters:
        `d` - whether debug information is output to the console

    - #### getDebug

          public boolean getDebug()

      Gets whether debug information is output to the console
      Overrides:
        `getDebug` in class `AbstractClassifier`
      Returns:
        whether debug information is output to the console

    - #### checkErrorRateTipText

          public java.lang.String checkErrorRateTipText()

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

    - #### setCheckErrorRate

          public void setCheckErrorRate(boolean d)

      Sets whether to check for error rate is in stopping criterion
      Parameters:
        `d` - whether to check for error rate is in stopping criterion

    - #### getCheckErrorRate

          public boolean getCheckErrorRate()

      Gets whether to check for error rate is in stopping criterion
      Returns:
        true if checking for error rate is in stopping criterion

    - #### usePruningTipText

          public java.lang.String usePruningTipText()

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

    - #### setUsePruning

          public void setUsePruning(boolean d)

      Sets whether pruning is performed
      Parameters:
        `d` - Whether pruning is performed

    - #### getUsePruning

          public boolean getUsePruning()

      Gets whether pruning is performed
      Returns:
        true if pruning is performed

    - #### getRuleset

          public java.util.ArrayList<Rule> getRuleset()

      Get the ruleset generated by Ripper
      Returns:
        the ruleset

    - #### getRuleStats

          public RuleStats getRuleStats(int pos)

      Get the statistics of the ruleset in the given position
      Parameters:
        `pos` - the position of the stats, assuming correct
      Returns:
        the statistics of the ruleset in the given position

    - #### getCapabilities

          public Capabilities getCapabilities()

      Returns default capabilities of the classifier.
      Specified by:
        `getCapabilities` in interface `Classifier`
      Specified by:
        `getCapabilities` in interface `CapabilitiesHandler`
      Overrides:
        `getCapabilities` in class `AbstractClassifier`
      Returns:
        the capabilities of this classifier
      See Also:
        `Capabilities`

    - #### buildClassifier

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

      Builds Ripper in the order of class frequencies. For each class it's built in two stages: building and optimization
      Specified by:
        `buildClassifier` in interface `Classifier`
      Parameters:
        `instances` - the training data
      Throws:
        `java.lang.Exception` - if classifier can't be built successfully

    - #### distributionForInstance

          public double[] distributionForInstance(Instance datum)

      Classify the test instance with the rule learner and provide the class distributions
      Specified by:
        `distributionForInstance` in interface `Classifier`
      Overrides:
        `distributionForInstance` in class `AbstractClassifier`
      Parameters:
        `datum` - the instance to be classified
      Returns:
        the distribution

    - #### toString

          public java.lang.String toString()

      Prints the all the rules of the rule learner.
      Overrides:
        `toString` in class `java.lang.Object`
      Returns:
        a textual description of the classifier

    - #### getRevision

          public java.lang.String getRevision()

      Returns the revision string.
      Specified by:
        `getRevision` in interface `RevisionHandler`
      Overrides:
        `getRevision` in class `AbstractClassifier`
      Returns:
        the revision

    - #### main

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

      Main method.
      Parameters:
        `args` - the options for the classifier