weka.filters.supervised.attribute

## Class ClassOrder

- java.lang.Object
- - weka.filters.Filter
  - - weka.filters.supervised.attribute.ClassOrder

- All Implemented Interfaces:
    java.io.Serializable, CapabilitiesHandler, CapabilitiesIgnorer, OptionHandler, RevisionHandler, SupervisedFilter

      public class ClassOrder
      extends Filter
      implements SupervisedFilter, OptionHandler

  Changes the order of the classes so that the class values are no longer of in the order specified in the header. The values will be in the order specified by the user -- it could be either in ascending/descending order by the class frequency or in random order. Note that this filter currently does not change the header, only the class values of the instances, so there is not much point in using it in conjunction with the FilteredClassifier. The value can also be converted back using 'originalValue(double value)' procedure.

  Valid options are:

       -R <seed>
        Specify the seed of randomization
        used to randomize the class
        order (default: 1)

       -C <order>
        Specify the class order to be
        sorted, could be 0: ascending
        1: descending and 2: random.(default: 0)

  Version:
    $Revision: 10215 $
  Author:
    Xin Xu (xx5@cs.waikato.ac.nz), Eibe Frank (eibe@cs.waikato.ac.nz)
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `FREQ_ASCEND` The class values are sorted in ascending order based on their frequencies
    `static int` | `FREQ_DESCEND` The class values are sorted in descending order based on their frequencies
    `static int` | `RANDOM` The class values are sorted in random order

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ClassOrder()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `batchFinished()` Signify that this batch of input to the filter is finished.
    `java.lang.String` | `classOrderTipText()` Returns the tip text for this property
    `double[]` | `distributionsByOriginalIndex(double[] before)` Convert the given class distribution back to the distributions with the original internal class index
    `Capabilities` | `getCapabilities()` Returns the Capabilities of this filter.
    `double[]` | `getClassCounts()` Get the class distribution of the sorted class values.
    `int` | `getClassOrder()` Get the wanted class order
    `java.lang.String[]` | `getOptions()` Gets the current settings of the filter.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `long` | `getSeed()` Get the current randomization seed
    `java.lang.String` | `globalInfo()` Returns a string describing this filter
    `boolean` | `input(Instance instance)` Input an instance for filtering.
    `java.util.Enumeration<Option>` | `listOptions()` Returns an enumeration describing the available options.
    `static void` | `main(java.lang.String[] argv)` Main method for testing this class.
    `double` | `originalValue(double value)` Return the original internal class value given the randomized class value, i.e.
    `java.lang.String` | `seedTipText()` Returns the tip text for this property
    `void` | `setClassOrder(int order)` Set the wanted class order
    `boolean` | `setInputFormat(Instances instanceInfo)` Sets the format of the input instances.
    `void` | `setOptions(java.lang.String[] options)` Parses a given list of options.
    `void` | `setSeed(long seed)` Set randomization seed

    - ### Methods inherited from class weka.filters.Filter

      `batchFilterFile, debugTipText, doNotCheckCapabilitiesTipText, filterFile, getCapabilities, getDebug, getDoNotCheckCapabilities, getOutputFormat, isFirstBatchDone, isNewBatch, isOutputFormatDefined, makeCopies, makeCopy, mayRemoveInstanceAfterFirstBatchDone, numPendingOutput, output, outputPeek, runFilter, setDebug, setDoNotCheckCapabilities, toString, useFilter, wekaStaticWrapper`

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

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

- - ### Field Detail

    - #### FREQ_ASCEND

          public static final int FREQ_ASCEND

      The class values are sorted in ascending order based on their frequencies
      See Also:
        Constant Field Values

    - #### FREQ_DESCEND

          public static final int FREQ_DESCEND

      The class values are sorted in descending order based on their frequencies
      See Also:
        Constant Field Values

    - #### RANDOM

          public static final int RANDOM

      The class values are sorted in random order
      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### ClassOrder

          public ClassOrder()

  - ### Method Detail

    - #### globalInfo

          public java.lang.String globalInfo()

      Returns a string describing this filter
      Returns:
        a description of the filter suitable for displaying in the explorer/experimenter gui

    - #### listOptions

          public java.util.Enumeration<Option> listOptions()

      Returns an enumeration describing the available options.
      Specified by:
        `listOptions` in interface `OptionHandler`
      Overrides:
        `listOptions` in class `Filter`
      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:

           -R <seed>
            Specify the seed of randomization
            used to randomize the class
            order (default: 1)

           -C <order>
            Specify the class order to be
            sorted, could be 0: ascending
            1: descending and 2: random.(default: 0)

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

    - #### 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

    - #### getSeed

          public long getSeed()

      Get the current randomization seed
      Returns:
        a seed

    - #### setSeed

          public void setSeed(long seed)

      Set randomization seed
      Parameters:
        `seed` - the set seed

    - #### classOrderTipText

          public java.lang.String classOrderTipText()

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

    - #### getClassOrder

          public int getClassOrder()

      Get the wanted class order
      Returns:
        class order

    - #### setClassOrder

          public void setClassOrder(int order)

      Set the wanted class order
      Parameters:
        `order` - the class order

    - #### getCapabilities

          public Capabilities getCapabilities()

      Returns the Capabilities of this filter.
      Specified by:
        `getCapabilities` in interface `CapabilitiesHandler`
      Overrides:
        `getCapabilities` in class `Filter`
      Returns:
        the capabilities of this object
      See Also:
        `Capabilities`

    - #### setInputFormat

          public boolean setInputFormat(Instances instanceInfo)
                                 throws java.lang.Exception

      Sets the format of the input instances.
      Overrides:
        `setInputFormat` in class `Filter`
      Parameters:
        `instanceInfo` - an Instances object containing the input instance structure (any instances contained in the object are ignored - only the structure is required).
      Returns:
        true if the outputFormat may be collected immediately
      Throws:
        `java.lang.Exception` - if no class index set or class not nominal

    - #### input

          public boolean input(Instance instance)

      Input an instance for filtering. Ordinarily the instance is processed and made available for output immediately. Some filters require all instances be read before producing output.
      Overrides:
        `input` in class `Filter`
      Parameters:
        `instance` - the input instance
      Returns:
        true if the filtered instance may now be collected with output().
      Throws:
        `java.lang.IllegalStateException` - if no input format has been defined.

    - #### batchFinished

          public boolean batchFinished()
                                throws java.lang.Exception

      Signify that this batch of input to the filter is finished. If the filter requires all instances prior to filtering, output() may now be called to retrieve the filtered instances. Any subsequent instances filtered should be filtered based on setting obtained from the first batch (unless the inputFormat has been re-assigned or new options have been set). This implementation sorts the class values and provide class counts in the output format
      Overrides:
        `batchFinished` in class `Filter`
      Returns:
        true if there are instances pending output
      Throws:
        `java.lang.IllegalStateException` - if no input structure has been defined,
        `java.lang.Exception` - if there was a problem finishing the batch.

    - #### getClassCounts

          public double[] getClassCounts()

      Get the class distribution of the sorted class values. If class is numeric it returns null
      Returns:
        the class counts

    - #### distributionsByOriginalIndex

          public double[] distributionsByOriginalIndex(double[] before)

      Convert the given class distribution back to the distributions with the original internal class index
      Parameters:
        `before` - the given class distribution
      Returns:
        the distribution converted back

    - #### originalValue

          public double originalValue(double value)
                               throws java.lang.Exception

      Return the original internal class value given the randomized class value, i.e. the string presentations of the two indices are the same. It's useful when the filter is used within a classifier so that the filtering procedure should be transparent to the evaluation
      Parameters:
        `value` - the given value
      Returns:
        the original internal value, -1 if not found
      Throws:
        `java.lang.Exception` - if the coverter table is not set yet

    - #### getRevision

          public java.lang.String getRevision()

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

    - #### main

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

      Main method for testing this class.
      Parameters:
        `argv` - should contain arguments to the filter: use -h for help