/*
* Encog(tm) Core v3.3 - Java Version
* http://www.heatonresearch.com/encog/
* https://github.com/encog/encog-java-core
* Copyright 2008-2014 Heaton Research, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package org.encog.util.normalize.output.nominal;
import java.util.ArrayList;
import java.util.List;
import org.encog.mathutil.Equilateral;
import org.encog.util.normalize.input.InputField;
import org.encog.util.normalize.output.BasicOutputField;
/**
* Allows nominal items to be encoded using the equilateral method. This maps
* the nominal items into an array of input or output values minus 1. This can
* sometimes provide a more accurate representation than the "one of" method.
* Based on: Guiver and Klimasauskas (1991).
*/
public class OutputEquilateral extends BasicOutputField {
/**
* THe nominal items.
*/
private final List<NominalItem> items = new ArrayList<NominalItem>();
/**
* The current equilateral matrix.
*/
private Equilateral equilateral;
/**
* The current value, which nominal item is selected.
*/
private int currentValue;
/**
* The high value to map into.
*/
private double high;
/**
* THe low value to map into.
*/
private double low;
/**
* Prodvide a default constructor for reflection.
*/
public OutputEquilateral() {
this(-1,1);
}
/**
* Create an equilateral output field with the specified high and low output
* values. These will often be 0 to 1 or -1 to 1.
*
* @param high
* The high output value.
* @param low
* The low output value.
*/
public OutputEquilateral(final double low, final double high) {
this.high = high;
this.low = low;
}
/**
* Add a nominal value based on a single value. This creates a 0.1 range
* around this value.
* @param inputField The input field this is based on.
* @param value The value.
*/
public void addItem(final InputField inputField, final double value) {
addItem(inputField, value - 0.1, value + 0.1);
}
/**
* Add a nominal item based on a range.
* @param inputField The input field to use.
* @param low The low value of the range.
* @param high The high value of the range.
*/
public void addItem(final InputField inputField, final double low,
final double high) {
final NominalItem item = new NominalItem(inputField, low, high);
this.items.add(item);
}
/**
* Calculate the value for the specified subfield.
* @param subfield The subfield to calculate for.
* @return The calculated value.
*/
public double calculate(final int subfield) {
return this.equilateral.encode(this.currentValue)[subfield];
}
/**
* @return The equalateral table being used.
*/
public Equilateral getEquilateral() {
return this.equilateral;
}
/**
* @return The high value of the range.
*/
public double getHigh() {
return this.high;
}
/**
* @return The low value of the range.
*/
public double getLow() {
return this.low;
}
/**
* This is the total number of nominal items minus 1.
*
* @return The number of subfields.
*/
public int getSubfieldCount() {
return this.items.size() - 1;
}
/**
* Determine which item's index is the value.
*/
public void rowInit() {
for (int i = 0; i < this.items.size(); i++) {
final NominalItem item = this.items.get(i);
if (item.isInRange()) {
this.currentValue = i;
break;
}
}
if (this.equilateral == null) {
this.equilateral = new Equilateral(this.items.size(), this.high,
this.low);
}
}
}