/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.cf.taste.impl.recommender.svd;
import java.util.Arrays;
import java.util.List;
import com.google.common.collect.Lists;
import org.apache.mahout.cf.taste.impl.TasteTestCase;
import org.apache.mahout.cf.taste.impl.common.FastByIDMap;
import org.apache.mahout.cf.taste.impl.common.FullRunningAverage;
import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
import org.apache.mahout.cf.taste.impl.common.RunningAverage;
import org.apache.mahout.cf.taste.impl.model.GenericDataModel;
import org.apache.mahout.cf.taste.impl.model.GenericPreference;
import org.apache.mahout.cf.taste.impl.model.GenericUserPreferenceArray;
import org.apache.mahout.cf.taste.impl.recommender.svd.ParallelSGDFactorizer.PreferenceShuffler;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.model.Preference;
import org.apache.mahout.cf.taste.model.PreferenceArray;
import org.apache.mahout.common.RandomUtils;
import org.apache.mahout.common.RandomWrapper;
import org.apache.mahout.math.DenseMatrix;
import org.apache.mahout.math.DenseVector;
import org.apache.mahout.math.Matrix;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.function.DoubleFunction;
import org.apache.mahout.math.function.VectorFunction;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class ParallelSGDFactorizerTest extends TasteTestCase {
protected DataModel dataModel;
protected int rank;
protected double lambda;
protected int numIterations;
private RandomWrapper random = (RandomWrapper) RandomUtils.getRandom();
protected Factorizer factorizer;
protected SVDRecommender svdRecommender;
private static final Logger logger = LoggerFactory.getLogger(ParallelSGDFactorizerTest.class);
private Matrix randomMatrix(int numRows, int numColumns, double range) {
double[][] data = new double[numRows][numColumns];
for (int i = 0; i < numRows; i++) {
for (int j = 0; j < numColumns; j++) {
double sqrtUniform = random.nextDouble();
data[i][j] = sqrtUniform * range;
}
}
return new DenseMatrix(data);
}
private void normalize(Matrix source, final double range) {
final double max = source.aggregateColumns(new VectorFunction() {
@Override
public double apply(Vector column) {
return column.maxValue();
}
}).maxValue();
final double min = source.aggregateColumns(new VectorFunction() {
@Override
public double apply(Vector column) {
return column.minValue();
}
}).minValue();
source.assign(new DoubleFunction() {
@Override
public double apply(double value) {
return (value - min) * range / (max - min);
}
});
}
public void setUpSyntheticData() throws Exception {
int numUsers = 2000;
int numItems = 1000;
double sparsity = 0.5;
this.rank = 20;
this.lambda = 0.000000001;
this.numIterations = 100;
Matrix users = randomMatrix(numUsers, rank, 1);
Matrix items = randomMatrix(rank, numItems, 1);
Matrix ratings = users.times(items);
normalize(ratings, 5);
FastByIDMap<PreferenceArray> userData = new FastByIDMap<PreferenceArray>();
for (int userIndex = 0; userIndex < numUsers; userIndex++) {
List<Preference> row= Lists.newArrayList();
for (int itemIndex = 0; itemIndex < numItems; itemIndex++) {
if (random.nextDouble() <= sparsity) {
row.add(new GenericPreference(userIndex, itemIndex, (float) ratings.get(userIndex, itemIndex)));
}
}
userData.put(userIndex, new GenericUserPreferenceArray(row));
}
dataModel = new GenericDataModel(userData);
}
public void setUpToyData() throws Exception {
this.rank = 3;
this.lambda = 0.01;
this.numIterations = 1000;
FastByIDMap<PreferenceArray> userData = new FastByIDMap<PreferenceArray>();
userData.put(1L, new GenericUserPreferenceArray(Arrays.asList(new GenericPreference(1L, 1L, 5.0f),
new GenericPreference(1L, 2L, 5.0f),
new GenericPreference(1L, 3L, 2.0f))));
userData.put(2L, new GenericUserPreferenceArray(Arrays.asList(new GenericPreference(2L, 1L, 2.0f),
new GenericPreference(2L, 3L, 3.0f),
new GenericPreference(2L, 4L, 5.0f))));
userData.put(3L, new GenericUserPreferenceArray(Arrays.asList(new GenericPreference(3L, 2L, 5.0f),
new GenericPreference(3L, 4L, 3.0f))));
userData.put(4L, new GenericUserPreferenceArray(Arrays.asList(new GenericPreference(4L, 1L, 3.0f),
new GenericPreference(4L, 4L, 5.0f))));
dataModel = new GenericDataModel(userData);
}
@Test
public void testPreferenceShufflerWithSyntheticData() throws Exception {
setUpSyntheticData();
ParallelSGDFactorizer.PreferenceShuffler shuffler = new PreferenceShuffler(dataModel);
shuffler.shuffle();
shuffler.stage();
FastByIDMap<FastByIDMap<Boolean>> checked = new FastByIDMap<FastByIDMap<Boolean>>();
for (int i = 0; i < shuffler.size(); i++) {
Preference pref=shuffler.get(i);
float value = dataModel.getPreferenceValue(pref.getUserID(), pref.getItemID());
assertEquals(pref.getValue(), value, 0.0);
if (!checked.containsKey(pref.getUserID())) {
checked.put(pref.getUserID(), new FastByIDMap<Boolean>());
}
assertNull(checked.get(pref.getUserID()).get(pref.getItemID()));
checked.get(pref.getUserID()).put(pref.getItemID(), true);
}
LongPrimitiveIterator userIDs = dataModel.getUserIDs();
int index=0;
while (userIDs.hasNext()) {
long userID = userIDs.nextLong();
PreferenceArray preferencesFromUser = dataModel.getPreferencesFromUser(userID);
for (Preference preference : preferencesFromUser) {
assertTrue(checked.get(preference.getUserID()).get(preference.getItemID()));
index++;
}
}
assertEquals(index, shuffler.size());
}
@Test
public void testFactorizerWithToyData() throws Exception {
setUpToyData();
long start = System.currentTimeMillis();
factorizer = new ParallelSGDFactorizer(dataModel, rank, lambda, numIterations, 0.01, 1, 0, 0);
Factorization factorization = factorizer.factorize();
long duration = System.currentTimeMillis() - start;
/* a hold out test would be better, but this is just a toy example so we only check that the
* factorization is close to the original matrix */
RunningAverage avg = new FullRunningAverage();
LongPrimitiveIterator userIDs = dataModel.getUserIDs();
LongPrimitiveIterator itemIDs;
while (userIDs.hasNext()) {
long userID = userIDs.nextLong();
for (Preference pref : dataModel.getPreferencesFromUser(userID)) {
double rating = pref.getValue();
Vector userVector = new DenseVector(factorization.getUserFeatures(userID));
Vector itemVector = new DenseVector(factorization.getItemFeatures(pref.getItemID()));
double estimate = userVector.dot(itemVector);
double err = rating - estimate;
avg.addDatum(err * err);
}
}
double sum = 0.0;
userIDs = dataModel.getUserIDs();
while (userIDs.hasNext()) {
long userID = userIDs.nextLong();
Vector userVector = new DenseVector(factorization.getUserFeatures(userID));
double regularization = userVector.dot(userVector);
sum += regularization;
}
itemIDs = dataModel.getItemIDs();
while (itemIDs.hasNext()) {
long itemID = itemIDs.nextLong();
Vector itemVector = new DenseVector(factorization.getUserFeatures(itemID));
double regularization = itemVector.dot(itemVector);
sum += regularization;
}
double rmse = Math.sqrt(avg.getAverage());
double loss = avg.getAverage() / 2 + lambda / 2 * sum;
logger.info("RMSE: " + rmse + ";\tLoss: " + loss + ";\tTime Used: " + duration);
assertTrue(rmse < 0.2);
}
@Test
public void testRecommenderWithToyData() throws Exception {
setUpToyData();
factorizer = new ParallelSGDFactorizer(dataModel, rank, lambda, numIterations, 0.01, 1, 0,0);
svdRecommender = new SVDRecommender(dataModel, factorizer);
/* a hold out test would be better, but this is just a toy example so we only check that the
* factorization is close to the original matrix */
RunningAverage avg = new FullRunningAverage();
LongPrimitiveIterator userIDs = dataModel.getUserIDs();
while (userIDs.hasNext()) {
long userID = userIDs.nextLong();
for (Preference pref : dataModel.getPreferencesFromUser(userID)) {
double rating = pref.getValue();
double estimate = svdRecommender.estimatePreference(userID, pref.getItemID());
double err = rating - estimate;
avg.addDatum(err * err);
}
}
double rmse = Math.sqrt(avg.getAverage());
logger.info("rmse: " + rmse);
assertTrue(rmse < 0.2);
}
@Test
public void testFactorizerWithWithSyntheticData() throws Exception {
setUpSyntheticData();
long start = System.currentTimeMillis();
factorizer = new ParallelSGDFactorizer(dataModel, rank, lambda, numIterations, 0.01, 1, 0, 0);
Factorization factorization = factorizer.factorize();
long duration = System.currentTimeMillis() - start;
/* a hold out test would be better, but this is just a toy example so we only check that the
* factorization is close to the original matrix */
RunningAverage avg = new FullRunningAverage();
LongPrimitiveIterator userIDs = dataModel.getUserIDs();
LongPrimitiveIterator itemIDs;
while (userIDs.hasNext()) {
long userID = userIDs.nextLong();
for (Preference pref : dataModel.getPreferencesFromUser(userID)) {
double rating = pref.getValue();
Vector userVector = new DenseVector(factorization.getUserFeatures(userID));
Vector itemVector = new DenseVector(factorization.getItemFeatures(pref.getItemID()));
double estimate = userVector.dot(itemVector);
double err = rating - estimate;
avg.addDatum(err * err);
}
}
double sum = 0.0;
userIDs = dataModel.getUserIDs();
while (userIDs.hasNext()) {
long userID = userIDs.nextLong();
Vector userVector = new DenseVector(factorization.getUserFeatures(userID));
double regularization=userVector.dot(userVector);
sum += regularization;
}
itemIDs = dataModel.getItemIDs();
while (itemIDs.hasNext()) {
long itemID = itemIDs.nextLong();
Vector itemVector = new DenseVector(factorization.getUserFeatures(itemID));
double regularization = itemVector.dot(itemVector);
sum += regularization;
}
double rmse = Math.sqrt(avg.getAverage());
double loss = avg.getAverage() / 2 + lambda / 2 * sum;
logger.info("RMSE: " + rmse + ";\tLoss: " + loss + ";\tTime Used: " + duration + "ms");
assertTrue(rmse < 0.2);
}
@Test
public void testRecommenderWithSyntheticData() throws Exception {
setUpSyntheticData();
factorizer= new ParallelSGDFactorizer(dataModel, rank, lambda, numIterations, 0.01, 1, 0, 0);
svdRecommender = new SVDRecommender(dataModel, factorizer);
/* a hold out test would be better, but this is just a toy example so we only check that the
* factorization is close to the original matrix */
RunningAverage avg = new FullRunningAverage();
LongPrimitiveIterator userIDs = dataModel.getUserIDs();
while (userIDs.hasNext()) {
long userID = userIDs.nextLong();
for (Preference pref : dataModel.getPreferencesFromUser(userID)) {
double rating = pref.getValue();
double estimate = svdRecommender.estimatePreference(userID, pref.getItemID());
double err = rating - estimate;
avg.addDatum(err * err);
}
}
double rmse = Math.sqrt(avg.getAverage());
logger.info("rmse: " + rmse);
assertTrue(rmse < 0.2);
}
}