Example usage for org.apache.mahout.cf.taste.hadoop MutableRecommendedItem set

Introduction

In this page you can find the example usage for org.apache.mahout.cf.taste.hadoop MutableRecommendedItem set.

Prototype

public void set(long itemID, float value) 

Source Link

Usage

From source file:hadoop.api.AggregateAndRecommendReducer.java

License:Apache License

/**
 * find the top entries in recommendationVector, map them to the real itemIDs and write back the result
 *//*  w  w  w .  ja v a2  s . c o m*/
private void writeRecommendedItems(VarLongWritable userID, Vector recommendationVector, Context context)
        throws IOException, InterruptedException {

    TopItemsQueue topKItems = new TopItemsQueue(recommendationsPerUser);

    for (Element element : recommendationVector.nonZeroes()) {
        int index = element.index();
        long itemID;
        if (indexItemIDMap != null && !indexItemIDMap.isEmpty()) {
            itemID = indexItemIDMap.get(index);
        } else { //we don't have any mappings, so just use the original
            itemID = index;
        }
        if (itemsToRecommendFor == null || itemsToRecommendFor.contains(itemID)) {
            float value = (float) element.get();
            if (!Float.isNaN(value)) {

                MutableRecommendedItem topItem = topKItems.top();
                if (value > topItem.getValue()) {
                    topItem.set(itemID, value);
                    topKItems.updateTop();
                }
            }
        }
    }

    List<RecommendedItem> topItems = topKItems.getTopItems();
    if (!topItems.isEmpty()) {
        recommendedItems.set(topItems);
        context.write(userID, recommendedItems);
    }
}

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