java.lang.Object
- weka.attributeSelection.ASSearch
- - weka.attributeSelection.LinearForwardSelection

All Implemented Interfaces:

java.io.Serializable, StartSetHandler, OptionHandler, RevisionHandler, TechnicalInformationHandler
```
public class LinearForwardSelection
extends ASSearch
implements OptionHandler, StartSetHandler, TechnicalInformationHandler
```
LinearForwardSelection:

Extension of BestFirst. Takes a restricted number of k attributes into account. Fixed-set selects a fixed number k of attributes, whereas k is increased in each step when fixed-width is selected. The search uses either the initial ordering to select the top k attributes, or performs a ranking (with the same evalutator the search uses later on). The search direction can be forward, or floating forward selection (with opitional backward search steps).

For more information see:

Martin Guetlein (2006). Large Scale Attribute Selection Using Wrappers. Freiburg, Germany.
Valid options are:
```
 -P <start set>
  Specify a starting set of attributes.
  Eg. 1,3,5-7.
```
```
 -D <0 = forward selection | 1 = floating forward selection>
  Forward selection method. (default = 0).
```
```
 -N <num>
  Number of non-improving nodes to
  consider before terminating search.
```
```
 -I
  Perform initial ranking to select the
  top-ranked attributes.
```
```
 -K <num>
  Number of top-ranked attributes that are 
  taken into account by the search.
```
```
 -T <0 = fixed-set | 1 = fixed-width>
  Type of Linear Forward Selection (default = 0).
```
```
 -S <num>
  Size of lookup cache for evaluated subsets.
  Expressed as a multiple of the number of
  attributes in the data set. (default = 1)
```
```
 -Z
  verbose on/off
```
Version:

$Revision: 6161 $

Author:

Martin Guetlein (martin.guetlein@gmail.com)

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type Field Description

static Tag[] TAGS_SEARCH_METHOD

static Tag[] TAGS_TYPE

Constructor Summary

Constructors
Constructor Description

LinearForwardSelection()
Constructor

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.lang.String`	`forwardSelectionMethodTipText()`	Returns the tip text for this property
`SelectedTag`	`getForwardSelectionMethod()`	Get the search direction
`int`	`getLookupCacheSize()`	Return the maximum size of the evaluated subset cache (expressed as a multiplier for the number of attributes in a data set.
`int`	`getNumUsedAttributes()`	Get the number of top-ranked attributes that taken into account by the search process.
`java.lang.String[]`	`getOptions()`	Gets the current settings of LinearForwardSelection.
`boolean`	`getPerformRanking()`	Get boolean if initial ranking should be performed to select the top-ranked attributes
`java.lang.String`	`getRevision()`	Returns the revision string.
`int`	`getSearchTermination()`	Get the termination criterion (number of non-improving nodes).
`java.lang.String`	`getStartSet()`	Returns a list of attributes (and or attribute ranges) as a String
`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.
`SelectedTag`	`getType()`	Get the type
`boolean`	`getVerbose()`	Get whether output is to be verbose
`java.lang.String`	`globalInfo()`	Returns a string describing this search method
`java.util.Enumeration`	`listOptions()`	Returns an enumeration describing the available options.
`java.lang.String`	`lookupCacheSizeTipText()`	Returns the tip text for this property
`java.lang.String`	`numUsedAttributesTipText()`	Returns the tip text for this property
`java.lang.String`	`performRankingTipText()`	Returns the tip text for this property
`int[]`	`search(ASEvaluation ASEval, Instances data)`	Searches the attribute subset space by linear forward selection
`java.lang.String`	`searchTerminationTipText()`	Returns the tip text for this property
`void`	`setForwardSelectionMethod(SelectedTag d)`	Set the search direction
`void`	`setLookupCacheSize(int size)`	Set the maximum size of the evaluated subset cache (hashtable).
`void`	`setNumUsedAttributes(int k)`	Set the number of top-ranked attributes that taken into account by the search process.
`void`	`setOptions(java.lang.String[] options)`	Parses a given list of options.
`void`	`setPerformRanking(boolean b)`	Perform initial ranking to select top-ranked attributes.
`void`	`setSearchTermination(int t)`	Set the numnber of non-improving nodes to consider before terminating search.
`void`	`setStartSet(java.lang.String startSet)`	Sets a starting set of attributes for the search.
`void`	`setType(SelectedTag t)`	Set the type
`void`	`setVerbose(boolean b)`	Set whether verbose output should be generated.
`java.lang.String`	`startSetTipText()`	Returns the tip text for this property
`java.lang.String`	`toString()`	returns a description of the search as a String
`java.lang.String`	`typeTipText()`	Returns the tip text for this property
`java.lang.String`	`verboseTipText()`	Returns the tip text for this property

Methods inherited from class weka.attributeSelection.ASSearch
forName, makeCopies

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

- Field Detail
  - TAGS_SEARCH_METHOD
```
public static final Tag[] TAGS_SEARCH_METHOD
```
  - TAGS_TYPE
```
public static final Tag[] TAGS_TYPE
```
- Constructor Detail
  - LinearForwardSelection
```
public LinearForwardSelection()
```
    Constructor
- Method Detail
  - globalInfo
```
public java.lang.String globalInfo()
```
    Returns a string describing this search method
    
    Returns:
    
    a description of the search method 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
    
    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
    Specify a starting set of attributes. Eg 1,4,7-9.
    -D <0 = forward selection | 1 = floating forward selection>
    Forward selection method of the search. (default = 0).
    -N
    Number of non improving nodes to consider before terminating search. (default = 5).
    -I
    Perform initial ranking to select top-ranked attributes.
    -K
    Number of top-ranked attributes that are taken into account.
    -T <0 = fixed-set | 1 = fixed-width>
    Typ of Linear Forward Selection (default = 0).
    -S
    Size of lookup cache for evaluated subsets. Expressed as a multiple of the number of attributes in the data set. (default = 1).
    -Z
    verbose on/off.
    
    Specified by:
    
    setOptions in interface OptionHandler
    
    Parameters:
    
    options - the list of options as an array of strings
    
    Throws:
    
    java.lang.Exception - if an option is not supported
  - setLookupCacheSize
```
public void setLookupCacheSize(int size)
```
    Set the maximum size of the evaluated subset cache (hashtable). This is expressed as a multiplier for the number of attributes in the data set. (default = 1).
    
    Parameters:
    
    size - the maximum size of the hashtable
  - getLookupCacheSize
```
public int getLookupCacheSize()
```
    Return the maximum size of the evaluated subset cache (expressed as a multiplier for the number of attributes in a data set.
    
    Returns:
    
    the maximum size of the hashtable.
  - lookupCacheSizeTipText
```
public java.lang.String lookupCacheSizeTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - startSetTipText
```
public java.lang.String startSetTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setStartSet
```
public void setStartSet(java.lang.String startSet)
                 throws java.lang.Exception
```
    Sets a starting set of attributes for the search. It is the search method's responsibility to report this start set (if any) in its toString() method.
    
    Specified by:
    
    setStartSet in interface StartSetHandler
    
    Parameters:
    
    startSet - a string containing a list of attributes (and or ranges), eg. 1,2,6,10-15.
    
    Throws:
    
    java.lang.Exception - if start set can't be set.
  - getStartSet
```
public java.lang.String getStartSet()
```
    Returns a list of attributes (and or attribute ranges) as a String
    
    Specified by:
    
    getStartSet in interface StartSetHandler
    
    Returns:
    
    a list of attributes (and or attribute ranges)
  - searchTerminationTipText
```
public java.lang.String searchTerminationTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setSearchTermination
```
public void setSearchTermination(int t)
                          throws java.lang.Exception
```
    Set the numnber of non-improving nodes to consider before terminating search.
    
    Parameters:
    
    t - the number of non-improving nodes
    
    Throws:
    
    java.lang.Exception - if t is less than 1
  - getSearchTermination
```
public int getSearchTermination()
```
    Get the termination criterion (number of non-improving nodes).
    
    Returns:
    
    the number of non-improving nodes
  - performRankingTipText
```
public java.lang.String performRankingTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setPerformRanking
```
public void setPerformRanking(boolean b)
```
    Perform initial ranking to select top-ranked attributes.
    
    Parameters:
    
    b - true if initial ranking should be performed
  - getPerformRanking
```
public boolean getPerformRanking()
```
    Get boolean if initial ranking should be performed to select the top-ranked attributes
    
    Returns:
    
    true if initial ranking should be performed
  - numUsedAttributesTipText
```
public java.lang.String numUsedAttributesTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setNumUsedAttributes
```
public void setNumUsedAttributes(int k)
                          throws java.lang.Exception
```
    Set the number of top-ranked attributes that taken into account by the search process.
    
    Parameters:
    
    k - the number of attributes
    
    Throws:
    
    java.lang.Exception - if k is less than 2
  - getNumUsedAttributes
```
public int getNumUsedAttributes()
```
    Get the number of top-ranked attributes that taken into account by the search process.
    
    Returns:
    
    the number of top-ranked attributes that taken into account
  - forwardSelectionMethodTipText
```
public java.lang.String forwardSelectionMethodTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setForwardSelectionMethod
```
public void setForwardSelectionMethod(SelectedTag d)
```
    Set the search direction
    
    Parameters:
    
    d - the direction of the search
  - getForwardSelectionMethod
```
public SelectedTag getForwardSelectionMethod()
```
    Get the search direction
    
    Returns:
    
    the direction of the search
  - typeTipText
```
public java.lang.String typeTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setType
```
public void setType(SelectedTag t)
```
    Set the type
    
    Parameters:
    
    t - the Linear Forward Selection type
  - getType
```
public SelectedTag getType()
```
    Get the type
    
    Returns:
    
    the Linear Forward Selection type
  - verboseTipText
```
public java.lang.String verboseTipText()
```
    Returns the tip text for this property
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setVerbose
```
public void setVerbose(boolean b)
```
    Set whether verbose output should be generated.
    
    Parameters:
    
    d - true if output is to be verbose.
  - getVerbose
```
public boolean getVerbose()
```
    Get whether output is to be verbose
    
    Returns:
    
    true if output will be verbose
  - getOptions
```
public java.lang.String[] getOptions()
```
    Gets the current settings of LinearForwardSelection.
    
    Specified by:
    
    getOptions in interface OptionHandler
    
    Returns:
    
    an array of strings suitable for passing to setOptions()
  - toString
```
public java.lang.String toString()
```
    returns a description of the search as a String
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    a description of the search
  - search
```
public int[] search(ASEvaluation ASEval,
                    Instances data)
             throws java.lang.Exception
```
    Searches the attribute subset space by linear forward selection
    
    Specified by:
    
    search in class ASSearch
    
    Parameters:
    
    ASEvaluator - the attribute evaluator to guide the search
    
    data - the training instances.
    
    Returns:
    
    an array (not necessarily ordered) of selected attribute indexes
    
    Throws:
    
    java.lang.Exception - if the search can't be completed
  - getRevision
```
public java.lang.String getRevision()
```
    Returns the revision string.
    
    Specified by:
    
    getRevision in interface RevisionHandler
    
    Overrides:
    
    getRevision in class ASSearch
    
    Returns:
    
    the revision

Fields
Modifier and Type	Field	Description
`static Tag[]`	`TAGS_SEARCH_METHOD`
`static Tag[]`	`TAGS_TYPE`

Class LinearForwardSelection

Field Summary

Constructor Summary

Method Summary

Methods inherited from class weka.attributeSelection.ASSearch

Methods inherited from class java.lang.Object

Field Detail

TAGS_SEARCH_METHOD

TAGS_TYPE

Constructor Detail

LinearForwardSelection

Method Detail

globalInfo

getTechnicalInformation

listOptions

setOptions

setLookupCacheSize

getLookupCacheSize

lookupCacheSizeTipText

startSetTipText

setStartSet

getStartSet

searchTerminationTipText

setSearchTermination

getSearchTermination

performRankingTipText

setPerformRanking

getPerformRanking

numUsedAttributesTipText

setNumUsedAttributes

getNumUsedAttributes

forwardSelectionMethodTipText

setForwardSelectionMethod

getForwardSelectionMethod

typeTipText

setType

getType

verboseTipText

setVerbose

getVerbose

getOptions

toString

search

getRevision