weka.filters.unsupervised.instance
Class ReservoirSample

java.lang.Object
  extended by weka.filters.Filter
      extended by weka.filters.unsupervised.instance.ReservoirSample
All Implemented Interfaces:
java.io.Serializable, CapabilitiesHandler, OptionHandler, UnsupervisedFilter

public class ReservoirSample
extends Filter
implements UnsupervisedFilter, OptionHandler

Produces a random subsample of a dataset using the reservoir sampling algorithm "R" of Vitter. The original data set does not have to fit into main memory, only the resevoir does.
For more information, see:

Vitter, J. S. Random Sampling with a Reservoir. ACM Transactions on Mathematical Software, Vol. 11, No. 1, March 1985. Pages 37-57.

BibTeX:

 @article{Vitter1985,
    author = {J. S. Vitter},
    journal = {ACM Transactions on Mathematical Software},
    number = {1}
    volume = {11}
    pages = {37-57},
    title = {Random Sampling with a Reservoir},
    year = {1985}
 }
 

Valid options are:

 -S <num>
  Specify the random number seed (default 1)
 -Z <num>
  The size of the output dataset, as a percentage of
  the input dataset (default 100)

Version:
$Revision: 1.2 $
Author:
Mark Hall (mhall{[at]}pentaho{[dot]}org)
See Also:
Serialized Form

Constructor Summary
ReservoirSample()
           
 
Method Summary
 boolean batchFinished()
          Signify that this batch of input to the filter is finished.
 Capabilities getCapabilities()
          Returns the Capabilities of this filter.
 java.lang.String[] getOptions()
          Gets the current settings of the filter.
 int getRandomSeed()
          Gets the random number seed.
 int getSampleSize()
          Gets the subsample size.
 java.lang.String globalInfo()
          Returns a string describing this filter
 boolean input(Instance instance)
          Input an instance for filtering.
 java.util.Enumeration listOptions()
          Returns an enumeration describing the available options.
static void main(java.lang.String[] argv)
          Main method for testing this class.
 java.lang.String randomSeedTipText()
          Returns the tip text for this property
 java.lang.String sampleSizeTipText()
          Returns the tip text for this property
 boolean setInputFormat(Instances instanceInfo)
          Sets the format of the input instances.
 void setOptions(java.lang.String[] options)
          Parses a given list of options.
 void setRandomSeed(int newSeed)
          Sets the random number seed.
 void setSampleSize(int newSampleSize)
          Sets the size of the subsample.
 
Methods inherited from class weka.filters.Filter
batchFilterFile, filterFile, getCapabilities, getOutputFormat, isFirstBatchDone, isNewBatch, isOutputFormatDefined, makeCopies, makeCopy, numPendingOutput, output, outputPeek, toString, useFilter, wekaStaticWrapper
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

ReservoirSample

public ReservoirSample()
Method Detail

globalInfo

public java.lang.String globalInfo()
Returns a string describing this filter

Returns:
a description of the classifier suitable for displaying in the explorer/experimenter gui

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:

 -S <num>
  Specify the random number seed (default 1)
 -Z <num>
  The size of the output dataset, as a percentage of
  the input dataset (default 100)

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

getOptions

public java.lang.String[] getOptions()
Gets the current settings of the filter.

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

randomSeedTipText

public java.lang.String randomSeedTipText()
Returns the tip text for this property

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

getRandomSeed

public int getRandomSeed()
Gets the random number seed.

Returns:
the random number seed.

setRandomSeed

public void setRandomSeed(int newSeed)
Sets the random number seed.

Parameters:
newSeed - the new random number seed.

sampleSizeTipText

public java.lang.String sampleSizeTipText()
Returns the tip text for this property

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

getSampleSize

public int getSampleSize()
Gets the subsample size.

Returns:
the subsample size

setSampleSize

public void setSampleSize(int newSampleSize)
Sets the size of the subsample.

Parameters:
newSampleSize - size of the subsample.

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 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 structure has been defined

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

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