Java LongPrimitiveIterator.next方法代码示例

import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator; //导入方法依赖的package包/类
private void intializeDelegate() {
    try {
    //iterate over all user ids
    LongPrimitiveIterator it = easyrecDataModelDelegate.getUserIDs();
    FastByIDMap<PreferenceArray> preferences = new FastByIDMap<PreferenceArray>(easyrecDataModelDelegate.getNumUsers());
    FastByIDMap<FastByIDMap<Long>> timestamps = new FastByIDMap<FastByIDMap<Long>>(easyrecDataModelDelegate.getNumUsers());
    while (it.hasNext()) {
        Long userId = it.next();
        //get preferences for each user
        PreferenceArray prefs = easyrecDataModelDelegate.getPreferencesFromUser(userId);
        preferences.put(userId,prefs);
        //get preference times for each user
        FastByIDMap<Long> timestampsForUser = new FastByIDMap<Long>(prefs.getIDs().length);
        for (Long itemId: prefs.getIDs()) {
            timestampsForUser.put(itemId,easyrecDataModelDelegate.getPreferenceTime(userId, itemId));
        }
        timestamps.put(userId, timestampsForUser);
    }
    //generate GenericDataModel
    setMaxPreference(easyrecDataModelDelegate.getMaxPreference());
    setMinPreference(easyrecDataModelDelegate.getMinPreference());
    this.inMemoryDelegate = new GenericDataModel(preferences,timestamps);
    } catch (TasteException e) {
        logger.warn("caught exception while reading preference data", e);
    }
}
 

import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator; //导入方法依赖的package包/类
/**
 * Like {@link MatrixUtils#transposeTimesSelf(FastByIDMap)}, but instead of computing MT * M, 
 * it computes MT * C * M, where C is a diagonal matrix of 1s and 0s. This is like pretending some
 * rows of M are 0.
 * 
 * @see MatrixUtils#transposeTimesSelf(FastByIDMap) 
 * @see #LOSS_IGNORES_UNSPECIFIED
 */
private static RealMatrix partialTransposeTimesSelf(FastByIDMap<float[]> M, 
                                                    int dimension, 
                                                    LongPrimitiveIterator keys) {
  RealMatrix result = new Array2DRowRealMatrix(dimension, dimension);
  while (keys.hasNext()) {
    long key = keys.next();
    float[] vector = M.get(key);
    for (int row = 0; row < dimension; row++) {
      float rowValue = vector[row];
      for (int col = 0; col < dimension; col++) {
        result.addToEntry(row, col, rowValue * vector[col]);
      }
    }
  }
  return result;
}
 

import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator; //导入方法依赖的package包/类
@Test
public void testEasyrecDataModel_getItemIDs() throws TasteException {
    EasyrecDataModel easyrecDataModel = new EasyrecDataModel(TENANT_ID, RATE_ACTION_TYPE_ID, HAS_RATING_VALUES, mahoutDataModelMappingDAO);
    LongPrimitiveIterator itemIds = easyrecDataModel.getItemIDs();

    String ids = "";
    while (itemIds.hasNext()) {
        ids += itemIds.next();
    }

    assertEquals("123", ids);

    //Test peek function of the iterator
    itemIds = easyrecDataModel.getItemIDs();


    ids = "";
    ids += itemIds.peek();

    while (itemIds.hasNext()) {
        ids += itemIds.peek() + "-" + itemIds.next();
        if (itemIds.hasNext()) {
            ids += "-" + itemIds.peek() + "-" + itemIds.peek() + "#";
        } else {
            ids += "#";
        }
    }
    assertEquals("11-1-2-2#2-2-3-3#3-3#", ids);
}
 

import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator; //导入方法依赖的package包/类
@Test
public void testEasyrecDataModel_getUserIDs() throws TasteException {
    EasyrecDataModel easyrecDataModel = new EasyrecDataModel(TENANT_ID, RATE_ACTION_TYPE_ID, HAS_RATING_VALUES, mahoutDataModelMappingDAO);
    LongPrimitiveIterator userIds = easyrecDataModel.getUserIDs();

    String ids = "";
    while (userIds.hasNext()) {
        ids += userIds.next();
    }

    assertEquals("12", ids);

}