Example usage for org.apache.mahout.cf.taste.impl.common FastIDSet intersectionSize

Introduction

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

Prototype

public int intersectionSize(FastIDSet other) 

Source Link

Document

Convenience method to quickly compute just the size of the intersection with another FastIDSet .

Usage

From source file:com.yelp.recommend.RestaurantSimilarity.java

License:Apache License

@Override
public double itemSimilarity(long itemID1, long itemID2) {
    if (itemID1 == itemID2) {
        return 1.0;
    }//from  w w w  .j a  v a2  s .c om
    RestaurantData data1 = RestaurantData.get(itemID1);
    RestaurantData data2 = RestaurantData.get(itemID2);
    if (data1 == null || data2 == null) {
        return 0.0;
    }

    // Tanimoto coefficient similarity based on attributes of restaurant

    FastIDSet attributes1 = data1.getAttributeSet();
    FastIDSet attributes2 = data2.getAttributeSet();
    if (attributes1 == null || attributes2 == null) {
        return 0.0;
    }
    int intersectionSize = attributes1.intersectionSize(attributes2);
    if (intersectionSize == 0) {
        return 0.0;
    }
    int unionSize = attributes1.size() + attributes2.size() - intersectionSize;
    return (double) intersectionSize / (double) unionSize;
}

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From source file:edu.uci.ics.sourcerer.ml.HammingDistanceSimilarity.java

License:Open Source License

@Override
public double userSimilarity(long userID1, long userID2) throws TasteException {

    FastIDSet prefs1 = dataModel.getItemIDsFromUser(userID1);
    FastIDSet prefs2 = dataModel.getItemIDsFromUser(userID2);

    int prefs1Size = prefs1.size();
    int prefs2Size = prefs2.size();
    int intersectionSize = prefs1Size < prefs2Size ? prefs2.intersectionSize(prefs1)
            : prefs1.intersectionSize(prefs2);
    if (intersectionSize == 0) {
        return Double.NaN;
    }//from  w w w  .  ja  v a  2s .  c  o m

    //int numItems = dataModel.getNumItems();
    //int numItems = Math.max(prefs1Size, prefs2Size);

    //int numItems = prefs1Size;

    //    double distance1 =  (double) (prefs1Size - intersectionSize)/(double) 2;
    //    double distance2 =  (double) (prefs2Size - intersectionSize)/(double) 2;
    //    double distance = (distance1 + distance2);

    double distance = (double) (prefs1Size - intersectionSize);

    double similarity = 1.0 / (1.0 + distance);
    //////System.out.println( prefs1Size  + ", " + prefs2Size + ", " + intersectionSize + ", " + similarity);
    return similarity;
}

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From source file:norbert.mynemo.core.recommendation.similarity.OriginalSpearmanCorrelationSimilarity.java

License:Apache License

/**
 * Returns the number of items that are rated by the two given users. An item rated by only one
 * user is not counted.//from   w  ww .ja v  a  2s  .  co m
 */
private int numCommonPreferences(final long userId1, final long userId2) throws TasteException {

    final FastIDSet prefs1 = dataModel.getItemIDsFromUser(userId1);
    final FastIDSet prefs2 = dataModel.getItemIDsFromUser(userId2);

    return prefs1.size() < prefs2.size() ? prefs2.intersectionSize(prefs1) : prefs1.intersectionSize(prefs2);
}

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