/*
* RapidMiner
*
* Copyright (C) 2001-2011 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.example;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import com.rapidminer.RapidMiner;
import com.rapidminer.datatable.DataTable;
import com.rapidminer.datatable.SimpleDataTable;
import com.rapidminer.datatable.SimpleDataTableRow;
import com.rapidminer.tools.Tools;
import com.rapidminer.tools.math.AverageVector;
/**
* AttributeWeights holds the information about the weights of attributes of an example set. It is delivered by several
* feature weighting algorithms or learning schemes. The use of a linked hash map ensures that the added features are
* stored in the same sequence they were added.
*
* @author Ingo Mierswa
*/
public class AttributeWeights extends AverageVector {
private static final long serialVersionUID = 7000978931118131854L;
/** Indicates that the weights should not be sorted at all. */
public static final int NO_SORTING = 0;
/** Indicates that the weights should be sorted in descending order. */
public static final int DECREASING = -1;
/** Indicates that the weights should be sorted in ascending order. */
public static final int INCREASING = 1;
/** Indicates that the the actual weights should be used for sorting. */
public static final int ORIGINAL_WEIGHTS = 0;
/** Indicates that the the absolute weights should be used for sorting. */
public static final int ABSOLUTE_WEIGHTS = 1;
/** This comparator sorts the names of attributes according to their weights. */
private class WeightComparator implements Comparator<String> {
/** Indicates if absolute weights should be used for sorting. */
private final int comparatorWeightType;
/** Indicates the sorting direction. */
private final int direction;
/** Creates a new weight comparator. */
public WeightComparator(int direction, int comparatorWeightType) {
this.comparatorWeightType = comparatorWeightType;
this.direction = direction;
}
/** Creates two attribute weights. */
@Override
public int compare(String o1, String o2) {
double w1 = weightMap.get(o1).getWeight();
double w2 = weightMap.get(o2).getWeight();
if (comparatorWeightType == ABSOLUTE_WEIGHTS) {
w1 = Math.abs(w1);
w2 = Math.abs(w2);
}
return Double.compare(w1, w2) * direction;
}
}
// ================================================================================
/** Indicates the type of sorting. */
private int sortType = NO_SORTING;
/** Indicates if absolute or actual weights should be used for sorting. */
private int weightType = ORIGINAL_WEIGHTS;
/** Maps the name of an attribute to the corresponding attribute weight. */
private Map<String, AttributeWeight> weightMap = new LinkedHashMap<String, AttributeWeight>();
/** Creates a new empty attribute weights object. */
public AttributeWeights() {
}
/**
* Creates a new attribute weights object containing a weight of 1 for each of the given input attributes.
*/
public AttributeWeights(ExampleSet exampleSet) {
for (Attribute attribute : exampleSet.getAttributes())
setWeight(attribute.getName(), 1.0d);
}
/** Clone constructor. */
private AttributeWeights(AttributeWeights weights) {
super();
Iterator i = weights.getAttributeNames().iterator();
while (i.hasNext()) {
String name = (String) i.next();
this.setWeight(name, weights.getWeight(name));
}
}
/** Returns the name of this AverageVector. */
@Override
public String getName() {
return "AttributeWeights";
}
/** Sets the weight for the attribute with the given name. */
public void setWeight(String name, double weight) {
AttributeWeight oldWeight = weightMap.get(name);
if (Double.isNaN(weight)) {
weightMap.remove(name);
super.removeAveragable(oldWeight);
} else if (oldWeight == null) {
AttributeWeight attWeight = new AttributeWeight(this, name, weight);
super.addAveragable(attWeight);
weightMap.put(name, attWeight);
} else {
oldWeight.setWeight(weight);
}
}
/**
* Returns the weight for the attribute with the given name. Returns Double.NaN if the weight for the queried
* attribute is not known.
*/
public double getWeight(String name) {
AttributeWeight weight = weightMap.get(name);
if (weight == null)
return Double.NaN;
else
return weight.getWeight();
}
/** Returns the currently used weight type. */
public int getWeightType() {
return weightType;
}
/** Returns the currently used weight type. */
public void setWeightType(int weightType) {
this.weightType = weightType;
}
/** Returns the currently used sorting type. */
public int getSortingType() {
return sortType;
}
/** Sets the currently used sorting type. */
public void setSortingType(int sortingType) {
this.sortType = sortingType;
}
/** Returns the number of features in this map. */
@Override
public int size() {
return weightMap.size();
}
/**
* This method removes the given attribute weight from this object.
*/
public void removeAttributeWeight(String attributeName) {
this.weightMap.remove(attributeName);
}
/**
* Returns an set of attribute names in this map ordered by their insertion time.
*/
public Set<String> getAttributeNames() {
return weightMap.keySet();
}
/**
* Since this average vector cannot be compared this method always returns 0.
*/
@Override
public int compareTo(Object o) {
return 0;
}
/** Returns true if both objects have the same weight map. */
@Override
public boolean equals(Object o) {
if (!(o instanceof AttributeWeights)) {
return false;
} else {
AttributeWeights other = (AttributeWeights) o;
return this.weightMap.equals(other.weightMap);
}
}
/** Returns the hash code of the weight map. */
@Override
public int hashCode() {
return this.weightMap.hashCode();
}
/**
* Sorts the given array of attribute names according to their weight, the sorting direction (ascending or
* descending), and with respect to the fact if original or absolute weights should be used. Ascending means that
* the attributes with the smallest weights come first.
*
* @param direction
* <code>INCREASING</code> or <code>DECREASING</code>
* @param comparatorType
* <code>WEIGHT</code> or <code>WEIGHT_ABSOLUTE</code>.
*/
public void sortByWeight(String[] attributeNames, int direction, int comparatorType) {
Arrays.sort(attributeNames, new WeightComparator(direction, comparatorType));
}
/**
* This will sort the weights either ascending if the boolean flag is true or descending. * @param direction
* <code>ASCENDING</code> or <code>DESCENDING</code>
*
* @param comparatorType
* <code>WEIGHT</code> or <code>WEIGHT_ABSOLUTE</code>.
*/
public void sort(int direction, int comparatorType) {
Map<String, AttributeWeight> newWeightMap = new LinkedHashMap<String, AttributeWeight>();
ArrayList<String> attributes = new ArrayList<String>(weightMap.keySet());
Collections.sort(attributes, new WeightComparator(direction, comparatorType));
for (String attributeName: attributes) {
newWeightMap.put(attributeName, weightMap.get(attributeName));
}
weightMap = newWeightMap;
}
/** Saves the attribute weights into an XML file. */
public void save(File file) throws IOException {
writeAttributeWeights(file, Tools.getDefaultEncoding());
}
public void writeAttributeWeights(File file, Charset encoding) throws IOException {
PrintWriter out = null;
try {
out = new PrintWriter(new FileWriter(file));
out.println("<?xml version=\"1.0\" encoding=\"" + encoding + "\"?>");
out.println("<attributeweights version=\"" + RapidMiner.getShortVersion() + "\">");
Iterator i = weightMap.keySet().iterator();
while (i.hasNext()) {
String key = (String) i.next();
double weight = weightMap.get(key).getWeight();
out.println(" <weight name=\"" + key + "\" value=\"" + weight + "\"/>");
}
out.println("</attributeweights>");
} catch (IOException e) {
throw e;
} finally {
if (out != null) {
out.close();
}
}
}
/** Loads a new AttributeWeights object from the given XML file. */
public static AttributeWeights load(File file) throws IOException {
AttributeWeights result = new AttributeWeights();
Document document = null;
try {
document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(file);
} catch (SAXException e1) {
throw new IOException(e1.getMessage());
} catch (ParserConfigurationException e1) {
throw new IOException(e1.getMessage());
}
Element attributeWeightsElement = document.getDocumentElement();
if (!attributeWeightsElement.getTagName().equals("attributeweights")) {
throw new IOException("Outer tag of attribute weights file must be <attributeweights>");
}
NodeList weights = attributeWeightsElement.getChildNodes();
for (int i = 0; i < weights.getLength(); i++) {
Node node = weights.item(i);
if (node instanceof Element) {
Element weightTag = (Element) node;
String tagName = weightTag.getTagName();
if (!tagName.equals("weight"))
throw new IOException("Only tags <weight> are allowed, was " + tagName);
String name = weightTag.getAttribute("name");
String value = weightTag.getAttribute("value");
double weight = 1.0d;
try {
weight = Double.parseDouble(value);
} catch (NumberFormatException e) {
throw new IOException("Only numerical weights are allowed for the 'value' attribute.");
}
result.setWeight(name, weight);
}
}
return result;
}
public String getExtension() {
return "wgt";
}
public String getFileDescription() {
return "attribute weights file";
}
/** Returns a string representation of this object. */
@Override
public String toString() {
return "AttributeWeights (containing weights for " + weightMap.size() + " attributes)";
}
/**
* Returns a deep clone of the attribute weights which provides the same sequence of attribute names.
*/
@Override
public Object clone() {
return new AttributeWeights(this);
}
/** This method normalizes all weights to the range 0 to 1. */
public void normalize() {
double weightMin = Double.POSITIVE_INFINITY;
double weightMax = Double.NEGATIVE_INFINITY;
for (String name : getAttributeNames()) {
double weight = Math.abs(getWeight(name));
weightMin = Math.min(weightMin, weight);
weightMax = Math.max(weightMax, weight);
}
Iterator<AttributeWeight> w = weightMap.values().iterator();
double diff = weightMax - weightMin;
while (w.hasNext()) {
AttributeWeight attributeWeight = w.next();
double newWeight = 1.0d;
if (diff != 0.0d)
newWeight = (Math.abs(attributeWeight.getWeight()) - weightMin) / diff;
attributeWeight.setWeight(newWeight);
}
}
public DataTable createDataTable() {
DataTable dataTable = new SimpleDataTable("Attribute Weights", new String[] { "attribute", "weight" });
for (Map.Entry<String, AttributeWeight> entry : weightMap.entrySet()) {
String attName = entry.getKey();
AttributeWeight attWeight = entry.getValue();
double index = dataTable.mapString(0, attName);
double weightValue = attWeight.getWeight();
double[] data = new double[] { index, weightValue };
dataTable.add(new SimpleDataTableRow(data, attName));
}
return dataTable;
}
}