weka.filters.unsupervised.attribute

## Class Center

- java.lang.Object
- - weka.filters.Filter
  - - weka.filters.unsupervised.attribute.PotentialClassIgnorer
    - - weka.filters.unsupervised.attribute.Center

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

      public class Center
      extends PotentialClassIgnorer
      implements UnsupervisedFilter, Sourcable

  Centers all numeric attributes in the given dataset to have zero mean (apart from the class attribute, if set).

  Valid options are:

       -unset-class-temporarily
        Unsets the class index temporarily before the filter is
        applied to the data.
        (default: no)

  Version:
    $Revision: 8034 $
  Author:
    Eibe Frank (eibe@cs.waikato.ac.nz), FracPete (fracpete at waikato dot ac dot nz)
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `Center()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `batchFinished()` Signify that this batch of input to the filter is finished.
    `Capabilities` | `getCapabilities()` Returns the Capabilities of this filter.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `java.lang.String` | `globalInfo()` Returns a string describing this filter
    `boolean` | `input(Instance instance)` Input an instance for filtering.
    `static void` | `main(java.lang.String[] args)` Main method for running this filter.
    `boolean` | `setInputFormat(Instances instanceInfo)` Sets the format of the input instances.
    `java.lang.String` | `toSource(java.lang.String className, Instances data)` Returns a string that describes the filter as source.

    - ### Methods inherited from class weka.filters.unsupervised.attribute.PotentialClassIgnorer

      `getIgnoreClass, getOptions, getOutputFormat, ignoreClassTipText, listOptions, setIgnoreClass, setOptions`

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

      `batchFilterFile, debugTipText, doNotCheckCapabilitiesTipText, filterFile, getCapabilities, getDebug, getDoNotCheckCapabilities, 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`

- - ### Constructor Detail

    - #### Center

          public Center()

  - ### 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

    - #### 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 `PotentialClassIgnorer`
      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 the input format can't be set successfully

    - #### input

          public boolean input(Instance instance)

      Input an instance for filtering. Filter requires all training 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 set.

    - #### batchFinished

          public boolean batchFinished()

      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.
      Overrides:
        `batchFinished` in class `Filter`
      Returns:
        true if there are instances pending output
      Throws:
        `java.lang.IllegalStateException` - if no input structure has been defined

    - #### toSource

          public java.lang.String toSource(java.lang.String className,
                                  Instances data)
                                    throws java.lang.Exception

      Returns a string that describes the filter as source. The filter will be contained in a class with the given name (there may be auxiliary classes), and will contain two methods with these signatures:

           // converts one row
           public static Object[] filter(Object[] i);
           // converts a full dataset (first dimension is row index)
           public static Object[][] filter(Object[][] i);

      where the array `i` contains elements that are either Double, String, with missing values represented as null. The generated code is public domain and comes with no warranty.
      Specified by:
        `toSource` in interface `Sourcable`
      Parameters:
        `className` - the name that should be given to the source class.
        `data` - the dataset used for initializing the filter
      Returns:
        the object source described by a string
      Throws:
        `java.lang.Exception` - if the source can't be computed

    - #### 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[] args)

      Main method for running this filter.
      Parameters:
        `args` - should contain arguments to the filter: use -h for help