Naive Bayes Classifier Bug ?

Hi Mahout,

In Naive Bayes, I think that a term does not exist in a training data
should not affect a score.
What do you think?

org.apache.mahout.classifier.
naivebayes.AbstractNaiveBayesClassifier

Before:
protected double getScoreForLabelInstance(int label, Vector instance) {
double result = 0.0;
for (Element e : instance.nonZeroes()) {
result += e.get() * getScoreForLabelFeature(label, e.index());

return result;

After:
protected double getScoreForLabelInstance(int label, Vector instance) {
double result = 0.0;
for (Element e : instance.nonZeroes()) {
int index = e.index();
double featureWeight = model.featureWeight(index);
if( featureLabelWeight != 0 ) {
result += e.get() * getScoreForLabelFeature(label, index);

return result;

Thanks,
Toyoharu