/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package org.apache.mahout.classifier.naivebayes;
/**
* Class implementing the Naive Bayes Classifier Algorithm
*
*/
public class ComplementaryNaiveBayesClassifier extends AbstractNaiveBayesClassifier {
public ComplementaryNaiveBayesClassifier(NaiveBayesModel model) {
super(model);
}
@Override
public double getScoreForLabelFeature(int label, int feature) {
NaiveBayesModel model = getModel();
double numerator = model.featureWeight(feature) - model.weight(label, feature) + model.alphaI();
double denominator = model.totalWeightSum() - model.labelWeight(label) + model.alphaI() * model.numFeatures();
return Math.log(numerator / denominator);
}
}