Example usage for org.apache.mahout.cf.taste.impl.common RunningAverage changeDatum

Introduction

In this page you can find the example usage for org.apache.mahout.cf.taste.impl.common RunningAverage changeDatum.

Prototype

void changeDatum(double delta);

Source Link

Usage

From source file:net.ufida.info.mahout.common.MemoryDiffStorage.java

License:Apache License

@Override
public void updateItemPref(long itemID, float prefDelta) {
    if (stdDevWeighted) {
        throw new UnsupportedOperationException("Can't update only when stdDevWeighted is set");
    }//from ww  w .  ja  v a  2  s.  com
    try {
        buildAverageDiffsLock.readLock().lock();
        for (Map.Entry<Long, FastByIDMap<RunningAverage>> entry : averageDiffs.entrySet()) {
            boolean matchesItemID1 = itemID == entry.getKey();
            for (Map.Entry<Long, RunningAverage> entry2 : entry.getValue().entrySet()) {
                RunningAverage average = entry2.getValue();
                if (matchesItemID1) {
                    average.changeDatum(-prefDelta);
                } else if (itemID == entry2.getKey()) {
                    average.changeDatum(prefDelta);
                }
            }
        }
        RunningAverage itemAverage = averageItemPref.get(itemID);
        if (itemAverage != null) {
            itemAverage.changeDatum(prefDelta);
        }
    } finally {
        buildAverageDiffsLock.readLock().unlock();
    }
}

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