Ejemplo n.º 1
0
    public static void Main(string[] args)
    {
        Assembly assembly = Assembly.GetExecutingAssembly();

        Assembly.LoadFile(Path.GetDirectoryName(assembly.Location) + Path.DirectorySeparatorChar + "MyMediaLiteExperimental.dll");

        AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(MyMediaLite.Util.Handlers.UnhandledExceptionHandler);
        Console.CancelKeyPress += new ConsoleCancelEventHandler(AbortHandler);

        // recommender arguments
        string method = "MostPopular";
        string recommender_options = string.Empty;

        // help/version
        bool show_help    = false;
        bool show_version = false;

        // variables for iteration search
        int    find_iter    = 0;
        int    max_iter     = 500;
        double auc_cutoff   = 0;
        double prec5_cutoff = 0;

        compute_fit = false;

        // other parameters
        string save_model_file = string.Empty;
        string load_model_file = string.Empty;
        int    random_seed     = -1;
        string prediction_file = string.Empty;

        test_ratio = 0;

        var p = new OptionSet()
        {
            // string-valued options
            { "training-file=", v => training_file = v },
            { "test-file=", v => test_file = v },
            { "recommender=", v => method = v },
            { "recommender-options=", v => recommender_options += " " + v },
            { "data-dir=", v => data_dir = v },
            { "user-attributes=", v => user_attributes_file = v },
            { "item-attributes=", v => item_attributes_file = v },
            { "user-relations=", v => user_relations_file = v },
            { "item-relations=", v => item_relations_file = v },
            { "save-model=", v => save_model_file = v },
            { "load-model=", v => load_model_file = v },
            { "prediction-file=", v => prediction_file = v },
            { "relevant-users=", v => relevant_users_file = v },
            { "relevant-items=", v => relevant_items_file = v },
            // integer-valued options
            { "find-iter=", (int v) => find_iter = v },
            { "max-iter=", (int v) => max_iter = v },
            { "random-seed=", (int v) => random_seed = v },
            { "predict-items-number=", (int v) => predict_items_number = v },
            // double-valued options
//			{ "epsilon=",             (double v) => epsilon      = v },
            { "auc-cutoff=", (double v) => auc_cutoff = v },
            { "prec5-cutoff=", (double v) => prec5_cutoff = v },
            { "test-ratio=", (double v) => test_ratio = v },
            // enum options
            //   * currently none *
            // boolean options
            { "compute-fit", v => compute_fit = v != null },
            { "online-evaluation", v => online_eval = v != null },
            { "filtered-evaluation", v => filtered_eval = v != null },
            { "help", v => show_help = v != null },
            { "version", v => show_version = v != null },
        };
        IList <string> extra_args = p.Parse(args);

        if (show_version)
        {
            ShowVersion();
        }
        if (show_help)
        {
            Usage(0);
        }

        bool no_eval = test_file == null;

        if (training_file == null)
        {
            Usage("Parameter --training-file=FILE is missing.");
        }

        if (extra_args.Count > 0)
        {
            Usage("Did not understand " + extra_args[0]);
        }

        if (online_eval && filtered_eval)
        {
            Usage("Combination of --online-eval and --filtered-eval is not (yet) supported.");
        }

        if (random_seed != -1)
        {
            MyMediaLite.Util.Random.InitInstance(random_seed);
        }

        recommender = Recommender.CreateItemRecommender(method);
        if (recommender == null)
        {
            Usage(string.Format("Unknown method: '{0}'", method));
        }

        Recommender.Configure(recommender, recommender_options, Usage);

        // load all the data
        LoadData();
        Utils.DisplayDataStats(training_data, test_data, recommender);

        TimeSpan time_span;

        if (find_iter != 0)
        {
            var iterative_recommender = (IIterativeModel)recommender;
            Console.WriteLine(recommender.ToString() + " ");

            if (load_model_file == string.Empty)
            {
                iterative_recommender.Train();
            }
            else
            {
                Recommender.LoadModel(iterative_recommender, load_model_file);
            }

            if (compute_fit)
            {
                Console.Write(string.Format(CultureInfo.InvariantCulture, "fit {0,0:0.#####} ", iterative_recommender.ComputeFit()));
            }

            var result = Evaluate();
            Items.DisplayResults(result);
            Console.WriteLine(" iteration " + iterative_recommender.NumIter);

            for (int i = (int)iterative_recommender.NumIter + 1; i <= max_iter; i++)
            {
                TimeSpan t = Utils.MeasureTime(delegate() {
                    iterative_recommender.Iterate();
                });
                training_time_stats.Add(t.TotalSeconds);

                if (i % find_iter == 0)
                {
                    if (compute_fit)
                    {
                        double fit = 0;
                        t = Utils.MeasureTime(delegate() { fit = iterative_recommender.ComputeFit(); });
                        fit_time_stats.Add(t.TotalSeconds);
                        Console.Write(string.Format(CultureInfo.InvariantCulture, "fit {0,0:0.#####} ", fit));
                    }

                    t = Utils.MeasureTime(delegate() { result = Evaluate(); });
                    eval_time_stats.Add(t.TotalSeconds);
                    Items.DisplayResults(result);
                    Console.WriteLine(" iteration " + i);

                    Recommender.SaveModel(recommender, save_model_file, i);
                    Predict(prediction_file, relevant_users_file, i);

                    if (result["AUC"] < auc_cutoff || result["prec@5"] < prec5_cutoff)
                    {
                        Console.Error.WriteLine("Reached cutoff after {0} iterations.", i);
                        Console.Error.WriteLine("DONE");
                        break;
                    }
                }
            }             // for
            DisplayStats();
        }
        else
        {
            if (load_model_file == string.Empty)
            {
                Console.Write(recommender.ToString() + " ");
                time_span = Utils.MeasureTime(delegate() { recommender.Train(); });
                Console.Write("training_time " + time_span + " ");
            }
            else
            {
                Recommender.LoadModel(recommender, load_model_file);
                Console.Write(recommender.ToString() + " ");
                // TODO is this the right time to load the model?
            }

            if (prediction_file != string.Empty)
            {
                Predict(prediction_file, relevant_users_file);
            }
            else if (!no_eval)
            {
                if (online_eval)
                {
                    time_span = Utils.MeasureTime(delegate() {
                        var result = Items.EvaluateOnline(recommender, test_data, training_data, relevant_users, relevant_items);                         // TODO support also for prediction outputs (to allow external evaluation)
                        Items.DisplayResults(result);
                    });
                }
                else
                {
                    time_span = Utils.MeasureTime(delegate() {
                        var result = Evaluate();
                        Items.DisplayResults(result);
                    });
                }
                Console.Write(" testing_time " + time_span);
            }
            Console.WriteLine();
        }
        Recommender.SaveModel(recommender, save_model_file);
    }
Ejemplo n.º 2
0
    static void Main(string[] args)
    {
        Assembly assembly = Assembly.GetExecutingAssembly();

        Assembly.LoadFile(Path.GetDirectoryName(assembly.Location) + Path.DirectorySeparatorChar + "MyMediaLiteExperimental.dll");

        AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(Handlers.UnhandledExceptionHandler);
        Console.CancelKeyPress += new ConsoleCancelEventHandler(AbortHandler);

        // recommender arguments
        string method = "BiasedMatrixFactorization";
        string recommender_options = string.Empty;

        // help/version
        bool show_help    = false;
        bool show_version = false;

        // arguments for iteration search
        int    find_iter   = 0;
        int    max_iter    = 500;
        double epsilon     = 0;
        double rmse_cutoff = double.MaxValue;
        double mae_cutoff  = double.MaxValue;

        // data arguments
        string data_dir             = string.Empty;
        string user_attributes_file = string.Empty;
        string item_attributes_file = string.Empty;
        string user_relations_file  = string.Empty;
        string item_relations_file  = string.Empty;

        // other arguments
        bool   online_eval      = false;
        bool   search_hp        = false;
        string save_model_file  = string.Empty;
        string load_model_file  = string.Empty;
        int    random_seed      = -1;
        string prediction_file  = string.Empty;
        string prediction_line  = "{0}\t{1}\t{2}";
        int    cross_validation = 0;
        double split_ratio      = 0;

        var p = new OptionSet()
        {
            // string-valued options
            { "training-file=", v => training_file = v },
            { "test-file=", v => test_file = v },
            { "recommender=", v => method = v },
            { "recommender-options=", v => recommender_options += " " + v },
            { "data-dir=", v => data_dir = v },
            { "user-attributes=", v => user_attributes_file = v },
            { "item-attributes=", v => item_attributes_file = v },
            { "user-relations=", v => user_relations_file = v },
            { "item-relations=", v => item_relations_file = v },
            { "save-model=", v => save_model_file = v },
            { "load-model=", v => load_model_file = v },
            { "prediction-file=", v => prediction_file = v },
            { "prediction-line=", v => prediction_line = v },
            // integer-valued options
            { "find-iter=", (int v) => find_iter = v },
            { "max-iter=", (int v) => max_iter = v },
            { "random-seed=", (int v) => random_seed = v },
            { "cross-validation=", (int v) => cross_validation = v },
            // double-valued options
            { "epsilon=", (double v) => epsilon = v },
            { "rmse-cutoff=", (double v) => rmse_cutoff = v },
            { "mae-cutoff=", (double v) => mae_cutoff = v },
            { "split-ratio=", (double v) => split_ratio = v },
            // enum options
            { "rating-type=", (RatingType v) => rating_type = v },
            { "file-format=", (RatingFileFormat v) => file_format = v },
            // boolean options
            { "compute-fit", v => compute_fit = v != null },
            { "online-evaluation", v => online_eval = v != null },
            { "search-hp", v => search_hp = v != null },
            { "help", v => show_help = v != null },
            { "version", v => show_version = v != null },
        };
        IList <string> extra_args = p.Parse(args);

        // TODO make sure interaction of --find-iter and --cross-validation works properly

        bool no_eval = test_file == null;

        if (show_version)
        {
            ShowVersion();
        }
        if (show_help)
        {
            Usage(0);
        }

        if (extra_args.Count > 0)
        {
            Usage("Did not understand " + extra_args[0]);
        }

        if (training_file == null)
        {
            Usage("Parameter --training-file=FILE is missing.");
        }

        if (cross_validation != 0 && split_ratio != 0)
        {
            Usage("--cross-validation=K and --split-ratio=NUM are mutually exclusive.");
        }

        if (random_seed != -1)
        {
            MyMediaLite.Util.Random.InitInstance(random_seed);
        }

        recommender = Recommender.CreateRatingPredictor(method);
        if (recommender == null)
        {
            Usage(string.Format("Unknown method: '{0}'", method));
        }

        Recommender.Configure(recommender, recommender_options, Usage);

        // ID mapping objects
        if (file_format == RatingFileFormat.KDDCUP_2011)
        {
            user_mapping = new IdentityMapping();
            item_mapping = new IdentityMapping();
        }

        // load all the data
        LoadData(data_dir, user_attributes_file, item_attributes_file, user_relations_file, item_relations_file, !online_eval);

        Console.Error.WriteLine(string.Format(CultureInfo.InvariantCulture, "ratings range: [{0}, {1}]", recommender.MinRating, recommender.MaxRating));

        if (split_ratio > 0)
        {
            var split = new RatingsSimpleSplit(training_data, split_ratio);
            recommender.Ratings = split.Train[0];
            training_data       = split.Train[0];
            test_data           = split.Test[0];
        }

        Utils.DisplayDataStats(training_data, test_data, recommender);

        if (find_iter != 0)
        {
            if (!(recommender is IIterativeModel))
            {
                Usage("Only iterative recommenders support find_iter.");
            }
            var iterative_recommender = (IIterativeModel)recommender;
            Console.WriteLine(recommender.ToString() + " ");

            if (load_model_file == string.Empty)
            {
                recommender.Train();
            }
            else
            {
                Recommender.LoadModel(iterative_recommender, load_model_file);
            }

            if (compute_fit)
            {
                Console.Write(string.Format(CultureInfo.InvariantCulture, "fit {0,0:0.#####} ", iterative_recommender.ComputeFit()));
            }

            MyMediaLite.Eval.Ratings.DisplayResults(MyMediaLite.Eval.Ratings.Evaluate(recommender, test_data));
            Console.WriteLine(" iteration " + iterative_recommender.NumIter);

            for (int i = (int)iterative_recommender.NumIter + 1; i <= max_iter; i++)
            {
                TimeSpan time = Utils.MeasureTime(delegate() {
                    iterative_recommender.Iterate();
                });
                training_time_stats.Add(time.TotalSeconds);

                if (i % find_iter == 0)
                {
                    if (compute_fit)
                    {
                        double fit = 0;
                        time = Utils.MeasureTime(delegate() {
                            fit = iterative_recommender.ComputeFit();
                        });
                        fit_time_stats.Add(time.TotalSeconds);
                        Console.Write(string.Format(CultureInfo.InvariantCulture, "fit {0,0:0.#####} ", fit));
                    }

                    Dictionary <string, double> results = null;
                    time = Utils.MeasureTime(delegate() { results = MyMediaLite.Eval.Ratings.Evaluate(recommender, test_data); });
                    eval_time_stats.Add(time.TotalSeconds);
                    MyMediaLite.Eval.Ratings.DisplayResults(results);
                    rmse_eval_stats.Add(results["RMSE"]);
                    Console.WriteLine(" iteration " + i);

                    Recommender.SaveModel(recommender, save_model_file, i);
                    if (prediction_file != string.Empty)
                    {
                        Prediction.WritePredictions(recommender, test_data, user_mapping, item_mapping, prediction_line, prediction_file + "-it-" + i);
                    }

                    if (epsilon > 0.0 && results["RMSE"] - rmse_eval_stats.Min() > epsilon)
                    {
                        Console.Error.WriteLine(string.Format(CultureInfo.InvariantCulture, "{0} >> {1}", results["RMSE"], rmse_eval_stats.Min()));
                        Console.Error.WriteLine("Reached convergence on training/validation data after {0} iterations.", i);
                        break;
                    }
                    if (results["RMSE"] > rmse_cutoff || results["MAE"] > mae_cutoff)
                    {
                        Console.Error.WriteLine("Reached cutoff after {0} iterations.", i);
                        break;
                    }
                }
            }             // for

            DisplayStats();
        }
        else
        {
            TimeSpan seconds;

            if (load_model_file == string.Empty)
            {
                if (cross_validation > 0)
                {
                    Console.Write(recommender.ToString());
                    Console.WriteLine();
                    var split   = new RatingCrossValidationSplit(training_data, cross_validation);
                    var results = MyMediaLite.Eval.Ratings.EvaluateOnSplit(recommender, split);                     // TODO if (search_hp)
                    MyMediaLite.Eval.Ratings.DisplayResults(results);
                    no_eval             = true;
                    recommender.Ratings = training_data;
                }
                else
                {
                    if (search_hp)
                    {
                        // TODO --search-hp-criterion=RMSE
                        double result = NelderMead.FindMinimum("RMSE", recommender);
                        Console.Error.WriteLine("estimated quality (on split) {0}", result.ToString(CultureInfo.InvariantCulture));
                        // TODO give out hp search time
                    }

                    Console.Write(recommender.ToString());
                    seconds = Utils.MeasureTime(delegate() { recommender.Train(); });
                    Console.Write(" training_time " + seconds + " ");
                }
            }
            else
            {
                Recommender.LoadModel(recommender, load_model_file);
                Console.Write(recommender.ToString() + " ");
            }

            if (!no_eval)
            {
                if (online_eval)                  // TODO support also for prediction outputs (to allow external evaluation)
                {
                    seconds = Utils.MeasureTime(delegate() { MyMediaLite.Eval.Ratings.DisplayResults(MyMediaLite.Eval.Ratings.EvaluateOnline(recommender, test_data)); });
                }
                else
                {
                    seconds = Utils.MeasureTime(delegate() { MyMediaLite.Eval.Ratings.DisplayResults(MyMediaLite.Eval.Ratings.Evaluate(recommender, test_data)); });
                }

                Console.Write(" testing_time " + seconds);
            }

            if (compute_fit)
            {
                Console.Write("fit ");
                seconds = Utils.MeasureTime(delegate() {
                    MyMediaLite.Eval.Ratings.DisplayResults(MyMediaLite.Eval.Ratings.Evaluate(recommender, training_data));
                });
                Console.Write(string.Format(CultureInfo.InvariantCulture, " fit_time {0,0:0.#####} ", seconds));
            }

            if (prediction_file != string.Empty)
            {
                seconds = Utils.MeasureTime(delegate() {
                    Console.WriteLine();
                    Prediction.WritePredictions(recommender, test_data, user_mapping, item_mapping, prediction_line, prediction_file);
                });
                Console.Error.Write("predicting_time " + seconds);
            }

            Console.WriteLine();
            Console.Error.WriteLine("memory {0}", Memory.Usage);
        }
        Recommender.SaveModel(recommender, save_model_file);
    }
Ejemplo n.º 3
0
    static void DoTrack2()
    {
        TimeSpan seconds;

        if (find_iter != 0)
        {
            if (!(recommender_validate is IIterativeModel))
            {
                Usage("Only iterative recommenders support find_iter.");
            }

            IIterativeModel iterative_recommender_validate = (IIterativeModel)recommender_validate;
            IIterativeModel iterative_recommender_final    = (IIterativeModel)recommender_final;
            Console.WriteLine();

            if (load_model_file == string.Empty)
            {
                recommender_validate.Train();                 // TODO parallelize
                if (prediction_file != string.Empty)
                {
                    recommender_final.Train();
                }
            }

            // evaluate and display results
            double error = KDDCup.EvaluateTrack2(recommender_validate, validation_candidates, validation_hits);
            Console.WriteLine(string.Format(CultureInfo.InvariantCulture, "ERR {0:0.######} {1}", error, iterative_recommender_validate.NumIter));

            for (int i = (int)iterative_recommender_validate.NumIter + 1; i <= max_iter; i++)
            {
                TimeSpan time = Utils.MeasureTime(delegate() {
                    iterative_recommender_validate.Iterate();                     // TODO parallelize
                    if (prediction_file != string.Empty)
                    {
                        iterative_recommender_final.Iterate();
                    }
                });
                training_time_stats.Add(time.TotalSeconds);

                if (i % find_iter == 0)
                {
                    time = Utils.MeasureTime(delegate() {                     // TODO parallelize
                        // evaluate
                        error = KDDCup.EvaluateTrack2(recommender_validate, validation_candidates, validation_hits);
                        err_eval_stats.Add(error);
                        Console.WriteLine(string.Format(CultureInfo.InvariantCulture, "ERR {0:0.######} {1}", error, i));

                        if (prediction_file != string.Empty)
                        {
                            if (predict_score)
                            {
                                Console.Error.WriteLine("Predicting validation scores ...");
                                KDDCup.PredictScoresTrack2(recommender_validate, validation_candidates, prediction_file + "-validate-it-" + i);
                                Console.Error.WriteLine("Predicting real scores ...");
                                KDDCup.PredictScoresTrack2(recommender_final, test_candidates, prediction_file + "-it-" + i);
                            }
                            else
                            {
                                KDDCup.PredictTrack2(recommender_validate, validation_candidates, prediction_file + "-validate-it-" + i);
                                KDDCup.PredictTrack2(recommender_final, test_candidates, prediction_file + "-it-" + i);
                            }
                        }
                    });
                    eval_time_stats.Add(time.TotalSeconds);

                    if (save_model_file != string.Empty)
                    {
                        Recommender.SaveModel(recommender_validate, save_model_file + "-validate", i);
                        if (prediction_file != string.Empty)
                        {
                            Recommender.SaveModel(recommender_final, save_model_file, i);
                        }
                    }

                    if (err_eval_stats.Last() > err_cutoff)
                    {
                        Console.Error.WriteLine("Reached cutoff after {0} iterations.", i);
                        break;
                    }

                    if (err_eval_stats.Last() > err_eval_stats.Min() + epsilon)
                    {
                        Console.Error.WriteLine(string.Format(CultureInfo.InvariantCulture, "Reached convergence (eps={0:0.######}) on training/validation data after {1} iterations.", epsilon, i));
                        break;
                    }

                    DisplayStats();
                }
            }             // for

            DisplayStats();
        }
        else
        {
            if (load_model_file == string.Empty)
            {
                seconds = Utils.MeasureTime(delegate() {                 // TODO parallelize
                    recommender_validate.Train();
                    if (prediction_file != string.Empty)
                    {
                        recommender_final.Train();
                    }
                });
                Console.Write(" training_time " + seconds + " ");
            }

            seconds = Utils.MeasureTime(delegate() {
                // evaluate
                double error = KDDCup.EvaluateTrack2(recommender_validate, validation_candidates, validation_hits);
                Console.Write(string.Format(CultureInfo.InvariantCulture, "ERR {0:0.######}", error));

                if (prediction_file != string.Empty)
                {
                    if (predict_score)
                    {
                        KDDCup.PredictScoresTrack2(recommender_validate, validation_candidates, prediction_file + "-validate");
                        KDDCup.PredictScoresTrack2(recommender_final, test_candidates, prediction_file);
                    }
                    else
                    {
                        KDDCup.PredictTrack2(recommender_validate, validation_candidates, prediction_file + "-validate");
                        KDDCup.PredictTrack2(recommender_final, test_candidates, prediction_file);
                    }
                }
            });
            Console.Write(" evaluation_time " + seconds + " ");

            if (save_model_file != string.Empty)
            {
                Recommender.SaveModel(recommender_validate, save_model_file + "-validate");
                if (prediction_file != string.Empty)
                {
                    Recommender.SaveModel(recommender_final, save_model_file);
                }
            }
        }

        Console.WriteLine();
    }
Ejemplo n.º 4
0
    static void DoTrack1()
    {
        var rating_predictor_validate = recommender as RatingPredictor;
        var rating_predictor_final    = rating_predictor_validate.Clone() as RatingPredictor;

        rating_predictor_final.Ratings = complete_ratings;

        Console.WriteLine("Validation split:");
        Utils.DisplayDataStats(training_ratings, validation_ratings, rating_predictor_validate);
        Console.WriteLine("Test split:");
        Utils.DisplayDataStats(complete_ratings, test_data, rating_predictor_final);

        if (find_iter != 0)
        {
            if (!(recommender is IIterativeModel))
            {
                Usage("Only iterative recommenders support find_iter.");
            }
            IIterativeModel iterative_recommender_validate = (MatrixFactorization)rating_predictor_validate;
            IIterativeModel iterative_recommender_final    = (MatrixFactorization)rating_predictor_final;
            Console.WriteLine(recommender.ToString() + " ");

            if (load_model_file == string.Empty)
            {
                iterative_recommender_validate.Train();
                iterative_recommender_final.Train();
            }
            else
            {
                Recommender.LoadModel(rating_predictor_final, "final-" + load_model_file);
            }

            if (compute_fit)
            {
                Console.Write(string.Format(CultureInfo.InvariantCulture, "fit {0:0.#####} ", iterative_recommender_validate.ComputeFit()));
            }

            MyMediaLite.Eval.Ratings.DisplayResults(MyMediaLite.Eval.Ratings.Evaluate(rating_predictor_validate, validation_ratings));
            Console.WriteLine(" " + iterative_recommender_validate.NumIter);

            for (int i = (int)iterative_recommender_validate.NumIter + 1; i <= max_iter; i++)
            {
                TimeSpan time = Utils.MeasureTime(delegate() {
                    iterative_recommender_validate.Iterate();

                    iterative_recommender_final.Iterate();                     // TODO parallelize this
                });
                training_time_stats.Add(time.TotalSeconds);


                if (i % find_iter == 0)
                {
                    if (compute_fit)
                    {
                        double fit = 0;
                        time = Utils.MeasureTime(delegate() {
                            fit = iterative_recommender_validate.ComputeFit();
                        });
                        fit_time_stats.Add(time.TotalSeconds);
                        Console.Write(string.Format(CultureInfo.InvariantCulture, "fit {0:0.#####} ", fit));
                    }

                    // evaluate and save stats
                    // TODO parallelize
                    Dictionary <string, double> results = null;
                    time = Utils.MeasureTime(delegate() {
                        results = MyMediaLite.Eval.Ratings.Evaluate(rating_predictor_validate, validation_ratings);
                        MyMediaLite.Eval.Ratings.DisplayResults(results);
                        rmse_eval_stats.Add(results["RMSE"]);
                        Console.WriteLine(" " + i);
                    });
                    eval_time_stats.Add(time.TotalSeconds);


                    // write out model files and predictions
                    if (save_model_file != string.Empty)
                    {
                        Recommender.SaveModel(rating_predictor_validate, save_model_file + "-validate", i);
                        Recommender.SaveModel(rating_predictor_final, save_model_file, i);
                    }
                    if (prediction_file != string.Empty)
                    {
                        if (track2)
                        {
                            KDDCup.PredictRatingsDouble(rating_predictor_validate, validation_candidates, prediction_file + "-validate-it-" + i);
                            KDDCup.PredictRatingsDouble(rating_predictor_final, test_data, prediction_file + "-it-" + i);
                        }
                        else
                        {
                            KDDCup.PredictRatings(rating_predictor_validate, validation_ratings, prediction_file + "-validate-it-" + i);
                            KDDCup.PredictRatings(rating_predictor_final, test_data, prediction_file + "-it-" + i);
                        }
                    }

                    // check whether we should abort
                    if (epsilon > 0 && results["RMSE"] > rmse_eval_stats.Min() + epsilon)
                    {
                        Console.Error.WriteLine(string.Format(CultureInfo.InvariantCulture, "{0} >> {1}", results["RMSE"], rmse_eval_stats.Min()));
                        Console.Error.WriteLine("Reached convergence on training/validation data after {0} iterations.", i);
                        break;
                    }
                    if (results["RMSE"] > rmse_cutoff || results["MAE"] > mae_cutoff)
                    {
                        Console.Error.WriteLine("Reached cutoff after {0} iterations.", i);
                        break;
                    }
                }
            }             // for

            DisplayIterationStats();
            Recommender.SaveModel(recommender, save_model_file);
        }
        else
        {
            TimeSpan seconds;

            if (!no_eval)
            {
                if (load_model_file == string.Empty)
                {
                    Console.Write(recommender.ToString());
                    if (cross_validation > 0)                     // TODO cross-validation could also be performed on the complete dataset
                    {                                             // TODO support track2
                        Console.WriteLine();
                        var split   = new RatingCrossValidationSplit(training_ratings, cross_validation);
                        var results = MyMediaLite.Eval.Ratings.EvaluateOnSplit(rating_predictor_validate, split);
                        MyMediaLite.Eval.Ratings.DisplayResults(results);
                        no_eval = true;
                        rating_predictor_validate.Ratings = training_ratings;
                    }
                    else
                    {
                        seconds = Utils.MeasureTime(delegate() { recommender.Train(); });
                        Console.Write(" training_time " + seconds + " ");
                        Recommender.SaveModel(recommender, save_model_file);
                    }
                }

                Console.Write(recommender.ToString() + " ");

                seconds = Utils.MeasureTime(
                    delegate() { MyMediaLite.Eval.Ratings.DisplayResults(MyMediaLite.Eval.Ratings.Evaluate(rating_predictor_validate, validation_ratings)); }
                    );
                Console.Write(" testing_time " + seconds);
            }

            Console.WriteLine();

            if (prediction_file != string.Empty)
            {
                Console.WriteLine("Prediction for KDD Cup Track 1:");
                seconds = Utils.MeasureTime(delegate() { rating_predictor_final.Train(); });
                Console.Write(" training_time " + seconds + " ");
                if (save_model_file != string.Empty)
                {
                    Recommender.SaveModel(rating_predictor_validate, save_model_file + "-validate");
                    Recommender.SaveModel(rating_predictor_final, save_model_file);
                }

                Console.WriteLine();
                seconds = Utils.MeasureTime(delegate() {
                    KDDCup.PredictRatingsDouble(rating_predictor_final, test_data, prediction_file);

                    if (track2)
                    {
                        KDDCup.PredictRatingsDouble(rating_predictor_validate, validation_candidates, prediction_file + "-validate");
                    }
                    else
                    {
                        KDDCup.PredictRatings(rating_predictor_validate, validation_ratings, prediction_file + "-validate");
                    }
                });
                Console.Error.WriteLine("predicting_time " + seconds);
            }
        }
    }