/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.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 com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeRole;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.SimpleAttributes;
import com.rapidminer.example.table.ViewAttribute;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.container.Tupel;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* 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, Sebastian Land
*/
public class MinMaxNormalizationModel extends AbstractNormalizationModel {
private static final long serialVersionUID = 5620317015578777169L;
/** The minimum value for each attribute after normalization. */
private final double min;
/** The maximum value for each attribute after normalization. */
private final double max;
private final HashMap<String, Tupel<Double, Double>> attributeRanges;
private final 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());
}
}
}
@Override
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;
}
@Override
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();
if (maxA == minA || min == max) {
return Math.min(Math.max(minA, min), max);
} else {
return (value - minA) / (maxA - minA) * (max - min) + min;
}
}
/**
* Returns a nicer name. Necessary since this model is defined as inner class.
*/
@Override
public String getName() {
return "MinMaxNormalizationModel";
}
/** Returns a string representation of this model. */
@Override
public String toString() {
return "Normalize between " + this.min + " and " + this.max;
}
public double getMin() {
return min;
}
public double getMax() {
return max;
}
public Map<String, Tupel<Double, Double>> getAttributeRanges() {
return attributeRanges;
}
public Set<String> getAttributeNames() {
return attributeNames;
}
}