@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);
}
private LenskitRecommenderEngine loadEngine() throws RecommenderBuildException, IOException {
File modelFile = options.get("model_file");
if (modelFile == null) {
logger.info("creating fresh recommender");
LenskitRecommenderEngineBuilder builder = LenskitRecommenderEngine.newBuilder();
for (LenskitConfiguration config : environment.loadConfigurations(getConfigFiles())) {
builder.addConfiguration(config);
}
builder.addConfiguration(input.getConfiguration());
Stopwatch timer = Stopwatch.createStarted();
LenskitRecommenderEngine engine = builder.build();
timer.stop();
logger.info("built recommender in {}", timer);
return engine;
} else {
logger.info("loading recommender from {}", modelFile);
LenskitRecommenderEngineLoader loader = LenskitRecommenderEngine.newLoader();
for (LenskitConfiguration config : environment.loadConfigurations(getConfigFiles())) {
loader.addConfiguration(config);
}
loader.addConfiguration(input.getConfiguration());
Stopwatch timer = Stopwatch.createStarted();
LenskitRecommenderEngine engine;
CompressionMode comp = CompressionMode.autodetect(modelFile);
InputStream input = new FileInputStream(modelFile);
try {
input = comp.wrapInput(input);
engine = loader.load(input);
} finally {
input.close();
}
timer.stop();
logger.info("loaded recommender in {}", timer);
return engine;
}
}
