Examples of PreferenceArray

org.apache.mahout.cf.taste.model.PreferenceArray
An alternate representation of an array of {@link Preference}. Implementations, in theory, can produce a more memory-efficient representation.

Examples of org.apache.mahout.cf.taste.model.PreferenceArray

    this.preferenceFromUsers = userData;
    FastByIDMap<Collection<Preference>> prefsForItems = new FastByIDMap<Collection<Preference>>();
    FastIDSet itemIDSet = new FastIDSet();
    int currentCount = 0;
    for (Map.Entry<Long,PreferenceArray> entry : preferenceFromUsers.entrySet()) {
      PreferenceArray prefs = entry.getValue();
      prefs.sortByItem();
      for (Preference preference : prefs) {
        long itemID = preference.getItemID();
        itemIDSet.add(itemID);
        List<Preference> prefsForItem = (List<Preference>) prefsForItems.get(itemID);
        if (prefsForItem == null) {

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

   * @throws NoSuchUserException
   *           if there is no such user
   */
  @Override
  public PreferenceArray getPreferencesFromUser(long userID) throws NoSuchUserException {
    PreferenceArray prefs = preferenceFromUsers.get(userID);
    if (prefs == null) {
      throw new NoSuchUserException();
    }
    return prefs;
  }

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

    return prefs;
  }
  
  @Override
  public FastIDSet getItemIDsFromUser(long userID) throws TasteException {
    PreferenceArray prefs = getPreferencesFromUser(userID);
    int size = prefs.length();
    FastIDSet result = new FastIDSet(size);
    for (int i = 0; i < size; i++) {
      result.add(prefs.getItemID(i));
    }
    return result;
  }

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

    return new LongPrimitiveArrayIterator(itemIDs);
  }
  
  @Override
  public PreferenceArray getPreferencesForItem(long itemID) throws NoSuchItemException {
    PreferenceArray prefs = preferenceForItems.get(itemID);
    if (prefs == null) {
      throw new NoSuchItemException();
    }
    return prefs;
  }

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

    return prefs;
  }
  
  @Override
  public Float getPreferenceValue(long userID, long itemID) throws TasteException {
    PreferenceArray prefs = getPreferencesFromUser(userID);
    int size = prefs.length();
    for (int i = 0; i < size; i++) {
      if (prefs.getItemID(i) == itemID) {
        return prefs.getValue(i);
      }
    }
    return null;
  }

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

    int length = itemIDs.length;
    if ((length == 0) || (length > 2)) {
      throw new IllegalArgumentException("Illegal number of item IDs: " + length);
    }
    if (length == 1) {
      PreferenceArray prefs = preferenceForItems.get(itemIDs[0]);
      return prefs == null ? 0 : prefs.length();
    } else {
      PreferenceArray prefs1 = preferenceForItems.get(itemIDs[0]);
      PreferenceArray prefs2 = preferenceForItems.get(itemIDs[1]);
      if ((prefs1 == null) || (prefs2 == null)) {
        return 0;
      }
      FastIDSet users1 = new FastIDSet(prefs1.length());
      int size1 = prefs1.length();
      for (int i = 0; i < size1; i++) {
        users1.add(prefs1.getUserID(i));
      }
      FastIDSet users2 = new FastIDSet(prefs2.length());
      int size2 = prefs2.length();
      for (int i = 0; i < size2; i++) {
        users2.add(prefs2.getUserID(i));
      }
      users1.retainAll(users2);
      return users1.size();
    }
  }

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

    
    DataModel dataModel = getDataModel();
    
    int numUsers = getDataModel().getNumUsers();
    for (long iitem : itemNeighborhood) {
      PreferenceArray iPrefs = getDataModel().getPreferencesForItem(iitem);
      int iSize = iPrefs.length();
      int j = 0;
      for (long jitem : itemNeighborhood) {
        double value = 0.0;
        for (int pi = 0; pi < iSize; pi++) {
          long v = iPrefs.getUserID(pi);
          if (v == userID) {
            continue;
          }
          Float pj = dataModel.getPreferenceValue(userID, jitem);
          if (pj != null) {
            value += iPrefs.getValue(pi) * pj;
          }
        }
        A[i][j] = value / numUsers;
        j++;
      }
      i++;
    }
    
    PreferenceArray iPrefs = getDataModel().getPreferencesForItem(itemID);
    int iSize = iPrefs.length();
    i = 0;
    for (long jitem : itemNeighborhood) {
      double value = 0.0;
      for (int pi = 0; pi < iSize; pi++) {
        long v = iPrefs.getUserID(pi);
        if (v == userID) {
          continue;
        }
        Float pj = dataModel.getPreferenceValue(userID, jitem);
        if (pj != null) {
          value += iPrefs.getValue(pi) * pj;
        }
      }
      b[i] = value / numUsers;
      i++;
    }

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

  
  @Override
  protected float doEstimatePreference(long theUserID, long itemID) throws TasteException {
    
    DataModel dataModel = getDataModel();
    PreferenceArray prefs = dataModel.getPreferencesFromUser(theUserID);
    int size = prefs.length();
    FastIDSet possibleItemIDs = new FastIDSet(size);
    for (int i = 0; i < size; i++) {
      possibleItemIDs.add(prefs.getItemID(i));
    }
    possibleItemIDs.remove(itemID);
    
    List<RecommendedItem> mostSimilar = mostSimilarItems(itemID, possibleItemIDs.iterator(),
      neighborhoodSize, null);

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

    try {
      buildAveragesLock.writeLock().lock();
      DataModel dataModel = getDataModel();
      LongPrimitiveIterator it = dataModel.getUserIDs();
      while (it.hasNext()) {
        PreferenceArray prefs = dataModel.getPreferencesFromUser(it.nextLong());
        int size = prefs.length();
        for (int i = 0; i < size; i++) {
          long itemID = prefs.getItemID(i);
          RunningAverage average = itemAverages.get(itemID);
          if (average == null) {
            average = new FullRunningAverage();
            itemAverages.put(itemID, average);
          }
          average.addDatum(prefs.getValue(i));
        }
      }
      averagesBuilt = true;
    } finally {
      buildAveragesLock.writeLock().unlock();

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Examples of org.apache.mahout.cf.taste.model.PreferenceArray

  }
  
  private long processOneUser(long averageCount, long userID) throws TasteException {
    log.debug("Processing prefs for user {}", userID);
    // Save off prefs for the life of this loop iteration
    PreferenceArray userPreferences = dataModel.getPreferencesFromUser(userID);
    int length = userPreferences.length();
    for (int i = 0; i < length - 1; i++) {
      float prefAValue = userPreferences.getValue(i);
      long itemIDA = userPreferences.getItemID(i);
      FastByIDMap<RunningAverage> aMap = averageDiffs.get(itemIDA);
      if (aMap == null) {
        aMap = new FastByIDMap<RunningAverage>();
        averageDiffs.put(itemIDA, aMap);
      }
      for (int j = i + 1; j < length; j++) {
        // This is a performance-critical block
        long itemIDB = userPreferences.getItemID(j);
        RunningAverage average = aMap.get(itemIDB);
        if ((average == null) && (averageCount < maxEntries)) {
          average = buildRunningAverage();
          aMap.put(itemIDB, average);
          averageCount++;
        }
        if (average != null) {
          average.addDatum(userPreferences.getValue(j) - prefAValue);
        }
        
      }
      RunningAverage itemAverage = averageItemPref.get(itemIDA);
      if (itemAverage == null) {

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