/*
* RapidMiner
*
* Copyright (C) 2001-2008 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.operator.preprocessing.normalization;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeRole;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.SimpleAttributes;
import com.rapidminer.example.table.ViewAttribute;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.preprocessing.PreprocessingModel;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.Tupel;
/**
* A simple model which can be used to transform all regular attributes into
* a value range between the given min and max values.
*
* @author Ingo Mierswa
* @version $Id: MinMaxNormalizationModel.java,v 1.10 2008/05/28 10:52:03 ingomierswa Exp $
*/
public class MinMaxNormalizationModel extends PreprocessingModel {
private static final long serialVersionUID = 5620317015578777169L;
/** The minimum value for each attribute after normalization. */
private double min;
/** The maximum value for each attribute after normalization. */
private double max;
private HashMap<String, Tupel<Double, Double>> attributeRanges;
private Set<String> attributeNames;
/** Create a new normalization model. */
public MinMaxNormalizationModel(ExampleSet exampleSet, double min, double max, HashMap<String, Tupel<Double, Double>> attributeRanges) {
super(exampleSet);
this.min = min;
this.max = max;
this.attributeRanges = attributeRanges;
attributeNames = new HashSet<String>();
for (Attribute attribute: exampleSet.getAttributes()) {
if (attribute.isNumerical()) {
attributeNames.add(attribute.getName());
}
}
}
/** Performs the transformation. */
public ExampleSet applyOnData(ExampleSet exampleSet) throws OperatorException {
for (Example example: exampleSet) {
for (Attribute attribute : exampleSet.getAttributes()) {
String attributeName = attribute.getName();
if (attributeRanges.containsKey(attributeName)) {
Tupel<Double, Double> range = attributeRanges.get(attributeName);
double value = example.getValue(attribute);
double minA = range.getFirst().doubleValue();
double maxA = range.getSecond().doubleValue();
example.setValue(attribute, (value - minA) / (maxA - minA) * (max - min) + min);
}
}
}
return exampleSet;
}
/**
* Returns a nicer name. Necessary since this model is defined as inner
* class.
*/
public String getName() {
return "MinMaxNormalizationModel";
}
/** Returns a string representation of this model. */
public String toString() {
return "Normalize between " + this.min + " and " + this.max;
}
public Attributes getTargetAttributes(ExampleSet viewParent) {
SimpleAttributes attributes = new SimpleAttributes();
// add special attributes to new attributes
Iterator<AttributeRole> roleIterator = viewParent.getAttributes().allAttributeRoles();
while (roleIterator.hasNext()) {
AttributeRole role = roleIterator.next();
if (role.isSpecial()) {
attributes.add(role);
}
}
// add regular attributes
for (Attribute attribute: viewParent.getAttributes()) {
if (!attribute.isNumerical() || !attributeNames.contains(attribute.getName())) {
attributes.addRegular(attribute);
} else {
// giving new attributes old name: connection to rangesMap
attributes.addRegular(new ViewAttribute(this, attribute, attribute.getName(), Ontology.NUMERICAL, null));
}
}
return attributes;
}
public double getValue(Attribute targetAttribute, double value) {
Tupel<Double, Double> ranges = attributeRanges.get(targetAttribute.getName());
double minA = ranges.getFirst().doubleValue();
double maxA = ranges.getSecond().doubleValue();
return (value - minA) / (maxA - minA) * (max - min) + min;
}
}