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Class weka.filters.SpreadSubsampleFilter

java.lang.Object
    |
    +----weka.filters.Filter
            |
            +----weka.filters.SpreadSubsampleFilter

public class SpreadSubsampleFilter
extends Filter
implements OptionHandler
Produces a random subsample of a dataset. The original dataset must fit entirely in memory. This filter allows you to specify the maximum "spread" between the rarest and most common class. For example, you may specify that there be at most a 2:1 difference in class frequencies. When used in batch mode, subsequent batches are not resampled. Valid options are:

-S num
Specify the random number seed (default 1).

-M num
The maximum class distribution spread.
0 = no maximum spread, 1 = uniform distribution, 10 = allow at most a 10:1 ratio between the classes (default 0)

-X num
The maximum count for any class value.
(default 0 = unlimited)

-W
Adjust weights so that total weight per class is maintained. Individual instance weighting is not preserved. (default no weights adjustment)

Version:
$Revision: 1.8 $
Author:
Stuart Inglis (stuart@intelligenesis.net)

Constructor Index

 o SpreadSubsampleFilter()
 

Method Index

 o batchFinished()
Signify that this batch of input to the filter is finished.
 o getAdjustWeights()
Returns true if instance weights will be adjusted to maintain total weight per class.
 o getDistributionSpread()
Gets the value for the distribution spread
 o getMaxCount()
Gets the value for the max count
 o getOptions()
Gets the current settings of the filter.
 o getRandomSeed()
Gets the random number seed.
 o input(Instance)
Input an instance for filtering.
 o listOptions()
Returns an enumeration describing the available options
 o main(String[])
Main method for testing this class.
 o setAdjustWeights(boolean)
Sets whether the instance weights will be adjusted to maintain total weight per class.
 o setDistributionSpread(double)
Sets the value for the distribution spread
 o setInputFormat(Instances)
Sets the format of the input instances.
 o setMaxCount(double)
Sets the value for the max count
 o setOptions(String[])
Parses a list of options for this object.
 o setRandomSeed(int)
Sets the random number seed.

Constructor Detail

 o SpreadSubsampleFilter
public SpreadSubsampleFilter()

Method Detail

 o getAdjustWeights
public boolean getAdjustWeights()
          Returns true if instance weights will be adjusted to maintain total weight per class.
Returns:
true if instance weights will be adjusted to maintain total weight per class.
 o setAdjustWeights
public void setAdjustWeights(boolean newAdjustWeights)
          Sets whether the instance weights will be adjusted to maintain total weight per class.
Parameters:
newAdjustWeights -
 o listOptions
public java.util.Enumeration listOptions()
          Returns an enumeration describing the available options
Returns:
an enumeration of all the available options
 o setOptions
public void setOptions(java.lang.String options[]) throws java.lang.Exception
          Parses a list of options for this object. Valid options are:

-S num
Specify the random number seed (default 1).

-M num
The maximum class distribution spread.
0 = no maximum spread, 1 = uniform distribution, 10 = allow at most a 10:1 ratio between the classes (default 0)

-X num
The maximum count for any class value.
(default 0 = unlimited)

-W
Adjust weights so that total weight per class is maintained. Individual instance weighting is not preserved. (default no weights adjustment)

Parameters:
options - the list of options as an array of strings
Throws:
java.lang.Exception - if an option is not supported
 o getOptions
public java.lang.String[] getOptions()
          Gets the current settings of the filter.
Returns:
an array of strings suitable for passing to setOptions
 o setDistributionSpread
public void setDistributionSpread(double spread)
          Sets the value for the distribution spread
Parameters:
spread - the new distribution spread
 o getDistributionSpread
public double getDistributionSpread()
          Gets the value for the distribution spread
Returns:
the distribution spread
 o setMaxCount
public void setMaxCount(double maxcount)
          Sets the value for the max count
Parameters:
spread - the new max count
 o getMaxCount
public double getMaxCount()
          Gets the value for the max count
Returns:
the max count
 o getRandomSeed
public int getRandomSeed()
          Gets the random number seed.
Returns:
the random number seed.
 o setRandomSeed
public void setRandomSeed(int newSeed)
          Sets the random number seed.
Parameters:
newSeed - the new random number seed.
 o setInputFormat
public boolean setInputFormat(Instances instanceInfo) throws java.lang.Exception
          Sets the format of the input instances.
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:
UnassignedClassException - if no class attribute has been set.
UnsupportedClassTypeException - if the class attribute is not nominal.
Overrides:
setInputFormat in class Filter
 o input
public boolean input(Instance instance)
          Input an instance for filtering. Filter requires all training instances be read before producing output.
Parameters:
instance - the input instance
Returns:
true if the filtered instance may now be collected with output().
Throws:
java.lang.IllegalStateException - if no input structure has been defined
Overrides:
input in class Filter
 o 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.
Returns:
true if there are instances pending output
Throws:
java.lang.IllegalStateException - if no input structure has been defined
Overrides:
batchFinished in class Filter
 o 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

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