/*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* RemovePercentage.java
* Copyright (C) 2002 Richard Kirkby
*
*/
package weka.filters.unsupervised.instance;
import weka.filters.*;
import weka.core.*;
import java.util.*;
/**
* This filter outputs a given percentage of a dataset.
*
* Valid options are: <p>
*
* -V <br>
* Specifies if inverse of selection is to be output.<p>
*
* -P percentage <br>
* The percentage of instances to select. (default 50)<p>
*
* @author Richard Kirkby (eibe@cs.waikato.ac.nz)
* @author Eibe Frank (eibe@cs.waikato.ac.nz)
* @version $Revision: 1.1.1.1 $
*/
public class RemovePercentage extends Filter
implements UnsupervisedFilter, OptionHandler {
/** Percentage of instances to select. */
private int 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 the options for this object. Valid options are: <p>
*
* -P percentage <br>
* The percentage of instances to select. (default 50)<p>
*
* -V <br>
* Specifies if inverse of selection is to be output.<p>
*
* @param options the list of options as an array of strings
* @exception 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(Integer.parseInt(percent));
} else {
setPercentage(50);
}
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 outputs 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 int getPercentage() {
return m_Percentage;
}
/**
* Sets the percentage of intances to select.
*
* @param percent the percentage
* @exception IllegalArgumentException if percenatge out of range
*/
public void setPercentage(int 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;
}
/**
* 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
* @exception Exception if the input format can't be set successfully
*/
public boolean setInputFormat(Instances instanceInfo) throws Exception {
super.setInputFormat(instanceInfo);
setOutputFormat(instanceInfo);
return true;
}
/**
* 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
* @exception 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 = 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));
}
}
m_NewBatch = true;
return (numPendingOutput() != 0);
}
/**
* Main method for testing this class.
*
* @param argv should contain arguments to the filter: use -h for help
*/
public static void main(String [] argv) {
try {
if (Utils.getFlag('b', argv)) {
Filter.batchFilterFile(new RemovePercentage(), argv);
} else {
Filter.filterFile(new RemovePercentage(), argv);
}
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
}
}