public override float?getPreferenceValue(long userID, long itemID)
        {
            FastIDSet set = this.preferenceFromUsers.get(userID);

            if (set == null)
            {
                throw new NoSuchUserException(userID);
            }
            if (set.contains(itemID))
            {
                return(1f);
            }
            return(null);
        }
        private static long[] getCommonItems(FastIDSet commonSet, IEnumerable <RecommendedItem> recs, int max)
        {
            long[] numArray = new long[max];
            int    num      = 0;

            foreach (RecommendedItem item in recs)
            {
                long key = item.getItemID();
                if (commonSet.contains(key))
                {
                    numArray[num++] = key;
                }
                if (num == max)
                {
                    return(numArray);
                }
            }
            return(numArray);
        }
        private static long[] getCommonItems(FastIDSet commonSet, PreferenceArray prefs1, int max)
        {
            long[] numArray = new long[max];
            int    num      = 0;

            for (int i = 0; i < prefs1.length(); i++)
            {
                long key = prefs1.getItemID(i);
                if (commonSet.contains(key))
                {
                    numArray[num++] = key;
                }
                if (num == max)
                {
                    return(numArray);
                }
            }
            return(numArray);
        }
        private static int mask(FastIDSet commonSet, FastIDSet otherSet, long maxItemID)
        {
            int num = 0;

            for (int i = 0; i <= maxItemID; i++)
            {
                if (commonSet.contains((long)i))
                {
                    if (otherSet.contains((long)i))
                    {
                        num++;
                    }
                    else
                    {
                        commonSet.remove((long)i);
                    }
                }
            }
            return(num);
        }
        public void processOtherUser(long userID, FastIDSet relevantItemIDs, FastByIDMap <PreferenceArray> trainingUsers, long otherUserID, DataModel dataModel)
        {
            PreferenceArray array = dataModel.getPreferencesFromUser(otherUserID);

            if (userID == otherUserID)
            {
                List <Preference> prefs = new List <Preference>(array.length());
                foreach (Preference preference in array)
                {
                    if (!relevantItemIDs.contains(preference.getItemID()))
                    {
                        prefs.Add(preference);
                    }
                }
                if (prefs.Count > 0)
                {
                    trainingUsers.put(otherUserID, new GenericUserPreferenceArray(prefs));
                }
            }
            else
            {
                trainingUsers.put(otherUserID, array);
            }
        }
        public IRStatistics evaluate(RecommenderBuilder recommenderBuilder, DataModelBuilder dataModelBuilder, DataModel dataModel, IDRescorer rescorer, int at, double relevanceThreshold, double evaluationPercentage)
        {
            int                num        = dataModel.getNumItems();
            RunningAverage     average    = new FullRunningAverage();
            RunningAverage     average2   = new FullRunningAverage();
            RunningAverage     average3   = new FullRunningAverage();
            RunningAverage     average4   = new FullRunningAverage();
            int                num2       = 0;
            int                num3       = 0;
            IEnumerator <long> enumerator = dataModel.getUserIDs();

            while (enumerator.MoveNext())
            {
                long current = enumerator.Current;
                if (this.random.nextDouble() < evaluationPercentage)
                {
                    Stopwatch stopwatch = new Stopwatch();
                    stopwatch.Start();
                    PreferenceArray prefs           = dataModel.getPreferencesFromUser(current);
                    double          num5            = double.IsNaN(relevanceThreshold) ? computeThreshold(prefs) : relevanceThreshold;
                    FastIDSet       relevantItemIDs = this.dataSplitter.getRelevantItemsIDs(current, at, num5, dataModel);
                    int             num6            = relevantItemIDs.size();
                    if (num6 > 0)
                    {
                        FastByIDMap <PreferenceArray> trainingUsers = new FastByIDMap <PreferenceArray>(dataModel.getNumUsers());
                        IEnumerator <long>            enumerator2   = dataModel.getUserIDs();
                        while (enumerator2.MoveNext())
                        {
                            this.dataSplitter.processOtherUser(current, relevantItemIDs, trainingUsers, enumerator2.Current, dataModel);
                        }
                        DataModel model = (dataModelBuilder == null) ? new GenericDataModel(trainingUsers) : dataModelBuilder.buildDataModel(trainingUsers);
                        try
                        {
                            model.getPreferencesFromUser(current);
                        }
                        catch (NoSuchUserException)
                        {
                            continue;
                        }
                        int num7 = num6 + model.getItemIDsFromUser(current).size();
                        if (num7 >= (2 * at))
                        {
                            Recommender            recommender = recommenderBuilder.buildRecommender(model);
                            int                    num8        = 0;
                            List <RecommendedItem> list        = recommender.recommend(current, at, rescorer);
                            foreach (RecommendedItem item in list)
                            {
                                if (relevantItemIDs.contains(item.getItemID()))
                                {
                                    num8++;
                                }
                            }
                            int count = list.Count;
                            if (count > 0)
                            {
                                average.addDatum(((double)num8) / ((double)count));
                            }
                            average2.addDatum(((double)num8) / ((double)num6));
                            if (num6 < num7)
                            {
                                average3.addDatum(((double)(count - num8)) / ((double)(num - num6)));
                            }
                            double num10 = 0.0;
                            double num11 = 0.0;
                            for (int i = 0; i < count; i++)
                            {
                                RecommendedItem item2 = list[i];
                                double          num13 = 1.0 / log2(i + 2.0);
                                if (relevantItemIDs.contains(item2.getItemID()))
                                {
                                    num10 += num13;
                                }
                                if (i < num6)
                                {
                                    num11 += num13;
                                }
                            }
                            if (num11 > 0.0)
                            {
                                average4.addDatum(num10 / num11);
                            }
                            num2++;
                            if (count > 0)
                            {
                                num3++;
                            }
                            stopwatch.Stop();
                            log.info("Evaluated with user {} in {}ms", new object[] { current, stopwatch.ElapsedMilliseconds });
                            log.info("Precision/recall/fall-out/nDCG/reach: {} / {} / {} / {} / {}", new object[] { average.getAverage(), average2.getAverage(), average3.getAverage(), average4.getAverage(), ((double)num3) / ((double)num2) });
                        }
                    }
                }
            }
            return(new IRStatisticsImpl(average.getAverage(), average2.getAverage(), average3.getAverage(), average4.getAverage(), ((double)num3) / ((double)num2)));
        }