/*
* 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.learner.tree;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.set.SplittedExampleSet;
/**
* Calculates frequencies and weights.
*
* @author Sebastian Land, Ingo Mierswa
* @version $Id: FrequencyCalculator.java,v 1.5 2008/05/09 19:22:52 ingomierswa Exp $
*/
public class FrequencyCalculator {
public FrequencyCalculator() {}
/** Returns an array of the size of the partitions.
* Each entry contains the sum of all weights of the
* corresponding partition. */
public double[] getPartitionWeights(SplittedExampleSet splitted) {
Attribute weightAttribute = splitted.getAttributes().getWeight();
double[] weights = new double[splitted.getNumberOfSubsets()];
for (int i = 0; i < splitted.getNumberOfSubsets(); i++) {
splitted.selectSingleSubset(i);
for (Example e : splitted) {
double weight = 1.0d;
if (weightAttribute != null) {
weight = e.getValue(weightAttribute);
}
weights[i] += weight;
}
}
return weights;
}
/** Returns an array of size of the number of different label
* values. Each entry corresponds to the weight sum of all
* examples with the current label. */
public double[] getLabelWeights(ExampleSet exampleSet) {
Attribute label = exampleSet.getAttributes().getLabel();
Attribute weightAttribute = exampleSet.getAttributes().getWeight();
double[] weights = new double[label.getMapping().size()];
for (Example e : exampleSet) {
int labelIndex = (int)e.getValue(label);
double weight = 1.0d;
if (weightAttribute != null) {
weight = e.getValue(weightAttribute);
}
weights[labelIndex] += weight;
}
return weights;
}
/** Returns the sum of the given weights. */
public double getTotalWeight(double[] weights) {
double sum = 0.0d;
for (double w : weights)
sum += w;
return sum;
}
}