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## weka.attributeSelection
Class CheckAttributeSelection

    java.lang.Object
      weka.core.Check
          weka.core.CheckScheme
              weka.attributeSelection.CheckAttributeSelection

All Implemented Interfaces:
  OptionHandler, RevisionHandler

    public class CheckAttributeSelection

extends CheckScheme

Class for examining the capabilities and finding problems with attribute selection schemes. If you implement an attribute selection using the WEKA.libraries, you should run the checks on it to ensure robustness and correct operation. Passing all the tests of this object does not mean bugs in the attribute selection don't exist, but this will help find some common ones.

Typical usage:

`java weka.attributeSelection.CheckAttributeSelection -W ASscheme_name -- ASscheme_options`

CheckAttributeSelection reports on the following:

- Scheme abilities
  - Possible command line options to the scheme
  - Whether the scheme can predict nominal, numeric, string, date or relational class attributes.
  - Whether the scheme can handle numeric predictor attributes
  - Whether the scheme can handle nominal predictor attributes
  - Whether the scheme can handle string predictor attributes
  - Whether the scheme can handle date predictor attributes
  - Whether the scheme can handle relational predictor attributes
  - Whether the scheme can handle multi-instance data
  - Whether the scheme can handle missing predictor values
  - Whether the scheme can handle missing class values
  - Whether a nominal scheme only handles 2 class problems
  - Whether the scheme can handle instance weights
- Correct functioning
  - Correct initialisation during search (i.e. no result changes when search is performed repeatedly)
  - Whether the scheme alters the data pased to it (number of instances, instance order, instance weights, etc)
- Degenerate cases
  - building scheme with zero instances
  - all but one predictor attribute values missing
  - all predictor attribute values missing
  - all but one class values missing
  - all class values missing

Running CheckAttributeSelection with the debug option set will output the training dataset for any failed tests.

The `weka.attributeSelection.AbstractAttributeSelectionTest` uses this class to test all the schemes. Any changes here, have to be checked in that abstract test class, too.

Valid options are:

     -D
      Turn on debugging output.

     -S
      Silent mode - prints nothing to stdout.

     -N <num>
      The number of instances in the datasets (default 20).

     -nominal <num>
      The number of nominal attributes (default 2).

     -nominal-values <num>
      The number of values for nominal attributes (default 1).

     -numeric <num>
      The number of numeric attributes (default 1).

     -string <num>
      The number of string attributes (default 1).

     -date <num>
      The number of date attributes (default 1).

     -relational <num>
      The number of relational attributes (default 1).

     -num-instances-relational <num>
      The number of instances in relational/bag attributes (default 10).

     -words <comma-separated-list>
      The words to use in string attributes.

     -word-separators <chars>
      The word separators to use in string attributes.

     -eval name [options]
      Full name and options of the evaluator analyzed.
      eg: weka.attributeSelection.CfsSubsetEval

     -search name [options]
      Full name and options of the search method analyzed.
      eg: weka.attributeSelection.Ranker

     -test <eval|search>
      The scheme to test, either the evaluator or the search method.
      (Default: eval)

     Options specific to evaluator weka.attributeSelection.CfsSubsetEval:

     -M
      Treat missing values as a seperate value.

     -L
      Don't include locally predictive attributes.

     Options specific to search method weka.attributeSelection.Ranker:

     -P <start set>
      Specify a starting set of attributes.
      Eg. 1,3,5-7.
      Any starting attributes specified are
      ignored during the ranking.

     -T <threshold>
      Specify a theshold by which attributes
      may be discarded from the ranking.

     -N <num to select>
      Specify number of attributes to select

Version:
  $Revision: 4783 $
Author:
  Len Trigg (trigg@cs.waikato.ac.nz), FracPete (fracpete at waikato dot ac dot nz)
See Also:
  `TestInstances`

Nested Class Summary

Nested classes/interfaces inherited from class weka.core.CheckScheme
`CheckScheme.PostProcessor`

Constructor Summary
`CheckAttributeSelection()`

Method Summary
`void` | `doTests()` Begin the tests, reporting results to System.out
`ASEvaluation` | `getEvaluator()` Get the current evaluator
`java.lang.String[]` | `getOptions()` Gets the current settings of the CheckAttributeSelection.
`java.lang.String` | `getRevision()` Returns the revision string.
`ASSearch` | `getSearch()` Get the current search method
`boolean` | `getTestEvaluator()` Gets whether the evaluator is being tested or the search method.
`java.util.Enumeration` | `listOptions()` Returns an enumeration describing the available options.
`static void` | `main(java.lang.String[] args)` Test method for this class
`void` | `setEvaluator(ASEvaluation value)` Set the evaluator to test.
`void` | `setOptions(java.lang.String[] options)` Parses a given list of options.
`void` | `setSearch(ASSearch value)` Set the search method to test.
`void` | `setTestEvaluator(boolean value)` Sets whether the evaluator or the search method is being tested.

Methods inherited from class weka.core.CheckScheme
`attributeTypeToString, getNumDate, getNumInstances, getNumInstancesRelational, getNumNominal, getNumNumeric, getNumRelational, getNumString, getPostProcessor, getWords, getWordSeparators, hasClasspathProblems, setNumDate, setNumInstances, setNumInstancesRelational, setNumNominal, setNumNumeric, setNumRelational, setNumString, setPostProcessor, setWords, setWordSeparators`

Methods inherited from class weka.core.Check
`getDebug, getSilent, setDebug, setSilent`

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

Constructor Detail

### CheckAttributeSelection

    public CheckAttributeSelection()

Method Detail

### listOptions

    public java.util.Enumeration listOptions()

  Returns an enumeration describing the available options.

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

       -D
        Turn on debugging output.

       -S
        Silent mode - prints nothing to stdout.

       -N <num>
        The number of instances in the datasets (default 20).

       -nominal <num>
        The number of nominal attributes (default 2).

       -nominal-values <num>
        The number of values for nominal attributes (default 1).

       -numeric <num>
        The number of numeric attributes (default 1).

       -string <num>
        The number of string attributes (default 1).

       -date <num>
        The number of date attributes (default 1).

       -relational <num>
        The number of relational attributes (default 1).

       -num-instances-relational <num>
        The number of instances in relational/bag attributes (default 10).

       -words <comma-separated-list>
        The words to use in string attributes.

       -word-separators <chars>
        The word separators to use in string attributes.

       -eval name [options]
        Full name and options of the evaluator analyzed.
        eg: weka.attributeSelection.CfsSubsetEval

       -search name [options]
        Full name and options of the search method analyzed.
        eg: weka.attributeSelection.Ranker

       -test <eval|search>
        The scheme to test, either the evaluator or the search method.
        (Default: eval)

       Options specific to evaluator weka.attributeSelection.CfsSubsetEval:

       -M
        Treat missing values as a seperate value.

       -L
        Don't include locally predictive attributes.

       Options specific to search method weka.attributeSelection.Ranker:

       -P <start set>
        Specify a starting set of attributes.
        Eg. 1,3,5-7.
        Any starting attributes specified are
        ignored during the ranking.

       -T <threshold>
        Specify a theshold by which attributes
        may be discarded from the ranking.

       -N <num to select>
        Specify number of attributes to select

  Specified by:
    `setOptions` in interface `OptionHandler`
  Overrides:
    `setOptions` in class `CheckScheme`
  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 CheckAttributeSelection.

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

### doTests

    public void doTests()

  Begin the tests, reporting results to System.out

  Specified by:
    `doTests` in class `CheckScheme`

### setEvaluator

    public void setEvaluator(ASEvaluation value)

  Set the evaluator to test.

  Parameters:
    `value` - the evaluator to use.

### getEvaluator

    public ASEvaluation getEvaluator()

  Get the current evaluator

  Returns:
    the current evaluator

### setSearch

    public void setSearch(ASSearch value)

  Set the search method to test.

  Parameters:
    `value` - the search method to use.

### getSearch

    public ASSearch getSearch()

  Get the current search method

  Returns:
    the current search method

### setTestEvaluator

    public void setTestEvaluator(boolean value)

  Sets whether the evaluator or the search method is being tested.

  Parameters:
    `value` - if true then the evaluator will be tested

### getTestEvaluator

    public boolean getTestEvaluator()

  Gets whether the evaluator is being tested or the search method.

  Returns:
    true if the evaluator is being tested

### getRevision

    public java.lang.String getRevision()

  Returns the revision string.

  Returns:
    the revision

### main

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

  Test method for this class

  Parameters:
    `args` - the commandline parameters

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