/* (non-Javadoc)
* @see org.apache.hadoop.mapreduce.Reducer#reduce(KEYIN, java.lang.Iterable, org.apache.hadoop.mapreduce.Reducer.Context)
*/
protected void reduce(TextInt key, Iterable<Tuple> values, Context context)
throws IOException, InterruptedException {
ratingCorrelations.clear();
++logCounter;
ratingStat = null;
for (Tuple value : values) {
if (((Integer) value.get(value.getSize() - 1)) == 0) {
// in rating correlation
ratingCorrelations.add(value.createClone());
context.getCounter("Predictor", "Rating correlation").increment(1);
} else if (((Integer) value.get(value.getSize() - 1)) == 1) {
// rating stat
ratingStat = value.createClone();
} else {
// in user rating
if (!ratingCorrelations.isEmpty()) {
String userID = value.getString(0);
rating = value.getInt(1);
if (userRatingWithContext) {
ratingContext = value.getString(2);
}
// all rating correlations
for (Tuple ratingCorrTup : ratingCorrelations) {
context.getCounter("Predictor", "User rating").increment(1);
itemID = ratingCorrTup.getString(0);
ratingCorr = ratingCorrTup.getInt(1);
weight = ratingCorrTup.getInt(2);
modifyCorrelation();
int predRating =
linearCorrelation
? (rating * ratingCorr) / maxRating
: (rating * correlationScale + ratingCorr) / maxRating;
if (predRating > 0) {
// userID, itemID, predicted rating, correlation length, correlation coeff, input
// rating std dev
ratingStdDev = ratingStat != null ? ratingStat.getInt(0) : -1;
if (userRatingWithContext) {
valueOut.set(
userID
+ fieldDelim
+ itemID
+ fieldDelim
+ ratingContext
+ fieldDelim
+ predRating
+ fieldDelim
+ weight
+ fieldDelim
+ ratingCorr
+ fieldDelim
+ ratingStdDev);
} else {
valueOut.set(
userID
+ fieldDelim
+ itemID
+ fieldDelim
+ predRating
+ fieldDelim
+ weight
+ fieldDelim
+ ratingCorr
+ fieldDelim
+ ratingStdDev);
}
context.write(NullWritable.get(), valueOut);
context.getCounter("Predictor", "Rating correlation").increment(1);
}
}
}
}
}
}
