@Test
public void testSnapshot() throws RecommenderBuildException {
List<Rating> rs = new ArrayList<Rating>();
rs.add(Ratings.make(1, 5, 2));
rs.add(Ratings.make(1, 7, 4));
rs.add(Ratings.make(8, 4, 5));
rs.add(Ratings.make(8, 5, 4));
EventDAO dao = EventCollectionDAO.create(rs);
LenskitConfiguration config = new LenskitConfiguration();
config.bind(EventDAO.class).to(dao);
config.bind(ItemScorer.class).to(UserUserItemScorer.class);
config.bind(NeighborFinder.class).to(SnapshotNeighborFinder.class);
LenskitRecommenderEngine engine = LenskitRecommenderEngine.build(config);
Recommender rec = engine.createRecommender();
assertThat(rec.getItemScorer(), instanceOf(UserUserItemScorer.class));
assertThat(rec.getItemRecommender(), instanceOf(TopNItemRecommender.class));
RatingPredictor pred = rec.getRatingPredictor();
assertThat(pred, instanceOf(SimpleRatingPredictor.class));
Recommender rec2 = engine.createRecommender();
assertThat(rec2.getItemScorer(), not(sameInstance(rec.getItemScorer())));
}
@SuppressWarnings("deprecation")
@Before
public void setup() throws RecommenderBuildException {
List<Rating> rs = new ArrayList<Rating>();
rs.add(Rating.create(1, 6, 4));
rs.add(Rating.create(2, 6, 2));
rs.add(Rating.create(1, 7, 3));
rs.add(Rating.create(2, 7, 2));
rs.add(Rating.create(3, 7, 5));
rs.add(Rating.create(4, 7, 2));
rs.add(Rating.create(1, 8, 3));
rs.add(Rating.create(2, 8, 4));
rs.add(Rating.create(3, 8, 3));
rs.add(Rating.create(4, 8, 2));
rs.add(Rating.create(5, 8, 3));
rs.add(Rating.create(6, 8, 2));
rs.add(Rating.create(1, 9, 3));
rs.add(Rating.create(3, 9, 4));
EventCollectionDAO dao = new EventCollectionDAO(rs);
LenskitConfiguration config = new LenskitConfiguration();
config.bind(EventDAO.class).to(dao);
config.bind(ItemScorer.class).to(ItemItemScorer.class);
// this is the default
config.bind(UserVectorNormalizer.class).to(DefaultUserVectorNormalizer.class);
config.bind(VectorNormalizer.class).to(IdentityVectorNormalizer.class);
LenskitRecommenderEngine engine = LenskitRecommenderEngine.build(config);
session = engine.createRecommender();
recommender = session.getItemRecommender();
}
@Override
@SuppressWarnings({"rawtypes", "unchecked"})
public void execute() throws IOException, RecommenderBuildException {
LenskitRecommenderEngine engine = loadEngine();
long user = options.getLong("user");
List<Long> items = options.get("items");
LenskitRecommender rec = engine.createRecommender();
RatingPredictor pred = rec.getRatingPredictor();
if (pred == null) {
logger.error("recommender has no rating predictor");
throw new UnsupportedOperationException("no rating predictor");
}
logger.info("predicting {} items", items.size());
Symbol pchan = getPrintChannel();
Stopwatch timer = Stopwatch.createStarted();
SparseVector preds = pred.predict(user, items);
Long2ObjectMap channel = null;
if (pchan != null) {
for (TypedSymbol sym : preds.getChannelSymbols()) {
if (sym.getRawSymbol().equals(pchan)) {
channel = preds.getChannel(sym);
}
}
}
for (VectorEntry e : preds) {
System.out.format(" %d: %.3f", e.getKey(), e.getValue());
if (channel != null) {
System.out.format(" (%s)", channel.get(e.getKey()));
}
System.out.println();
}
timer.stop();
logger.info("predicted for {} items in {}", items.size(), timer);
}
