/*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* RemovePercentage.java
* Copyright (C) 2002-2012 University of Waikato, Hamilton, New Zealand
*
*/
package weka.filters.unsupervised.instance;
import java.util.Enumeration;
import java.util.Vector;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.RevisionUtils;
import weka.core.Utils;
import weka.filters.Filter;
import weka.filters.UnsupervisedFilter;
/**
<!-- globalinfo-start -->
* A filter that removes a given percentage of a dataset.
* <p/>
<!-- globalinfo-end -->
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -P <percentage>
* Specifies percentage of instances to select. (default 50)
* </pre>
*
* <pre> -V
* Specifies if inverse of selection is to be output.
* </pre>
*
<!-- options-end -->
*
* @author Richard Kirkby (eibe@cs.waikato.ac.nz)
* @author Eibe Frank (eibe@cs.waikato.ac.nz)
* @version $Revision: 8034 $
*/
public class RemovePercentage
extends Filter
implements UnsupervisedFilter, OptionHandler {
/** for serialization */
static final long serialVersionUID = 2150341191158533133L;
/** Percentage of instances to select. */
private double m_Percentage = 50;
/** Indicates if inverse of selection is to be output. */
private boolean m_Inverse = false;
/**
* Gets an enumeration describing the available options..
*
* @return an enumeration of all the available options.
*/
public Enumeration listOptions() {
Vector newVector = new Vector(2);
newVector.addElement(new Option(
"\tSpecifies percentage of instances to select. (default 50)\n",
"P", 1, "-P <percentage>"));
newVector.addElement(new Option(
"\tSpecifies if inverse of selection is to be output.\n",
"V", 0, "-V"));
return newVector.elements();
}
/**
* Parses a given list of options. <p/>
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -P <percentage>
* Specifies percentage of instances to select. (default 50)
* </pre>
*
* <pre> -V
* Specifies if inverse of selection is to be output.
* </pre>
*
<!-- options-end -->
*
* @param options the list of options as an array of strings
* @throws Exception if an option is not supported
*/
public void setOptions(String[] options) throws Exception {
String percent = Utils.getOption('P', options);
if (percent.length() != 0) {
setPercentage(Double.parseDouble(percent));
} else {
setPercentage(50.0);
}
setInvertSelection(Utils.getFlag('V', options));
if (getInputFormat() != null) {
setInputFormat(getInputFormat());
}
}
/**
* Gets the current settings of the filter.
*
* @return an array of strings suitable for passing to setOptions
*/
public String [] getOptions() {
String [] options = new String [5];
int current = 0;
options[current++] = "-P"; options[current++] = "" + getPercentage();
if (getInvertSelection()) {
options[current++] = "-V";
}
while (current < options.length) {
options[current++] = "";
}
return options;
}
/**
* Returns a string describing this filter
*
* @return a description of the filter suitable for
* displaying in the explorer/experimenter gui
*/
public String globalInfo() {
return "A filter that removes a given percentage of a dataset.";
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String percentageTipText() {
return "The percentage of the data to select.";
}
/**
* Gets the percentage of instances to select.
*
* @return the percentage.
*/
public double getPercentage() {
return m_Percentage;
}
/**
* Sets the percentage of intances to select.
*
* @param percent the percentage
* @throws IllegalArgumentException if percentage out of range
*/
public void setPercentage(double percent) {
if (percent < 0 || percent > 100) {
throw new IllegalArgumentException("Percentage must be between 0 and 100.");
}
m_Percentage = percent;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String invertSelectionTipText() {
return "Whether to invert the selection.";
}
/**
* Gets if selection is to be inverted.
*
* @return true if the selection is to be inverted
*/
public boolean getInvertSelection() {
return m_Inverse;
}
/**
* Sets if selection is to be inverted.
*
* @param inverse true if inversion is to be performed
*/
public void setInvertSelection(boolean inverse) {
m_Inverse = inverse;
}
/**
* Returns the Capabilities of this filter.
*
* @return the capabilities of this object
* @see Capabilities
*/
public Capabilities getCapabilities() {
Capabilities result = super.getCapabilities();
result.disableAll();
// attributes
result.enableAllAttributes();
result.enable(Capability.MISSING_VALUES);
// class
result.enableAllClasses();
result.enable(Capability.MISSING_CLASS_VALUES);
result.enable(Capability.NO_CLASS);
return result;
}
/**
* Sets the format of the input instances.
*
* @param instanceInfo an Instances object containing the input instance
* structure (any instances contained in the object are ignored - only the
* structure is required).
* @return true because outputFormat can be collected immediately
* @throws Exception if the input format can't be set successfully
*/
public boolean setInputFormat(Instances instanceInfo) throws Exception {
super.setInputFormat(instanceInfo);
setOutputFormat(instanceInfo);
return true;
}
/**
* Input an instance for filtering. Ordinarily the instance is processed
* and made available for output immediately. Some filters require all
* instances be read before producing output.
*
* @param instance the input instance
* @return true if the filtered instance may now be
* collected with output().
* @throws IllegalStateException if no input format has been set.
*/
public boolean input(Instance instance) {
if (getInputFormat() == null) {
throw new IllegalStateException("No input instance format defined");
}
if (m_NewBatch) {
resetQueue();
m_NewBatch = false;
}
if (isFirstBatchDone()) {
push(instance);
return true;
}
else {
bufferInput(instance);
return false;
}
}
/**
* Signify that this batch of input to the filter is
* finished. Output() may now be called to retrieve the filtered
* instances.
*
* @return true if there are instances pending output
* @throws IllegalStateException if no input structure has been defined
*/
public boolean batchFinished() {
if (getInputFormat() == null) {
throw new IllegalStateException("No input instance format defined");
}
// Push instances for output into output queue
Instances toFilter = getInputFormat();
int cutOff = (int) Math.round(toFilter.numInstances() * m_Percentage / 100);
if (m_Inverse) {
for (int i = 0; i < cutOff; i++) {
push(toFilter.instance(i));
}
} else {
for (int i = cutOff; i < toFilter.numInstances(); i++) {
push(toFilter.instance(i));
}
}
flushInput();
m_NewBatch = true;
m_FirstBatchDone = true;
return (numPendingOutput() != 0);
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 8034 $");
}
/**
* Main method for testing this class.
*
* @param argv should contain arguments to the filter: use -h for help
*/
public static void main(String [] argv) {
runFilter(new RemovePercentage(), argv);
}
}