public static void AnalyzeSearchWordSentiment(string indexPath, string field, string[] keywords, int printDocumentCnt = 10, string histogramField = null)
        {
            var searcher = LuceneOperations.GetIndexSearcher(indexPath);
            var reader   = searcher.GetIndexReader();
            var docIDs   = LuceneOperations.Search(searcher, StringOperations.GetMergedString(keywords, " "), field);

            Console.WriteLine("Find {0}% ({1}/{2}) documents containing: {3}", (100.0 * docIDs.Count / reader.NumDocs()), docIDs.Count, reader.NumDocs(), StringOperations.GetMergedString(keywords, " "));

            var              progress      = new ProgramProgress(docIDs.Count);
            var              sentiAnalyzer = new SentimentAnalyzer();
            SentimentType    sentimentType;
            double           sentimentScore;
            HeapSortDouble   hsdPos     = new HeapSortDouble(printDocumentCnt);
            HeapSortDouble   hsdNeg     = new HeapSortDouble(printDocumentCnt);
            Counter <string> counterPos = null;
            Counter <string> counterNeg = null;
            Counter <string> counterNeu = null;

            if (histogramField != null)
            {
                counterPos = new Counter <string>();
                counterNeg = new Counter <string>();
                counterNeu = new Counter <string>();
            }
            int posCnt = 0;
            int negCnt = 0;
            int neuCnt = 0;

            foreach (var docID in docIDs)
            {
                var document = reader.Document(docID);
                var content  = document.Get(field);
                sentiAnalyzer.GetSentiment(content, out sentimentType, out sentimentScore);

                switch (sentimentType)
                {
                case SentimentType.Positive:
                    posCnt++;
                    hsdPos.Insert(docID, Math.Abs(sentimentScore));
                    if (histogramField != null)
                    {
                        counterPos.Add(document.Get(histogramField));
                    }
                    break;

                case SentimentType.Negative:
                    negCnt++;
                    hsdNeg.Insert(docID, Math.Abs(sentimentScore));
                    if (histogramField != null)
                    {
                        counterNeg.Add(document.Get(histogramField));
                    }
                    break;

                case SentimentType.Neutral:
                    neuCnt++;
                    if (histogramField != null)
                    {
                        counterNeu.Add(document.Get(histogramField));
                    }
                    break;

                default:
                    throw new NotImplementedException();
                }

                progress.PrintIncrementExperiment();
            }

            Console.WriteLine("Positive document ratio {0}% ({1}/{2})", Math.Round(100.0 * posCnt / docIDs.Count), posCnt, docIDs.Count);
            Console.WriteLine("Negatvie document ratio {0}% ({1}/{2})", Math.Round(100.0 * negCnt / docIDs.Count), negCnt, docIDs.Count);
            Console.WriteLine("Neutral document ratio {0}% ({1}/{2})", Math.Round(100.0 * neuCnt / docIDs.Count), neuCnt, docIDs.Count);

            Console.WriteLine(StringOperations.WrapWithDash("Positive documents"));
            foreach (var kvp in hsdPos.GetSortedDictionary())
            {
                Console.WriteLine(kvp.Value + "\t" + reader.Document(kvp.Key).Get(field));
            }

            Console.WriteLine(StringOperations.WrapWithDash("Negative documents"));
            foreach (var kvp in hsdNeg.GetSortedDictionary())
            {
                Console.WriteLine(kvp.Value + "\t" + reader.Document(kvp.Key).Get(field));
            }

            progress.PrintTotalTime();

            if (histogramField != null)
            {
                string[]           featureStrings = new[] { "Pos", "Neg", "Neu" };
                Counter <string>[] counters       = new[] { counterPos, counterNeg, counterNeu };
                for (int i = 0; i < featureStrings.Length; i++)
                {
                    Console.WriteLine(StringOperations.WrapWithDash(histogramField + " " + featureStrings[i]));
                    int index = 0;
                    foreach (var kvp in counters[i].GetCountDictionary().OrderByDescending(kvp => kvp.Value))
                    {
                        Console.WriteLine(kvp.Key + "\t" + kvp.Value);
                        if (++index >= 100)
                        {
                            break;
                        }
                    }
                }
            }

            Console.ReadKey();
        }
        public void Start()
        {
            if (!outputpath.EndsWith("\\"))
            {
                outputpath += "\\";
            }

            var tokenizerConfig = new TokenizeConfig(tokenizeConfigStr);

            var searcher    = LuceneOperations.GetIndexSearcher(inputpath);
            var max_doc_num = (int)(searchDocRatio * searcher.GetIndexReader().NumDocs());
            var scoredDocs  = LuceneOperations.Search(searcher, searchfield, keywords, max_doc_num);

            int  iter      = 0;
            bool bContinue = threshold == 0 ? false : true;

            while (bContinue && iter < 5)
            {
                iter++;
                Console.WriteLine("iteration------------------" + iter);
                List <string> keywordsNew;
                #region Calculate Keywords
                var counter = new Counter <string>();
                foreach (var scoredDoc in scoredDocs)
                {
                    var doc     = searcher.Doc(scoredDoc.doc);
                    var content = doc.Get(searchfield);
                    foreach (var word in NLPOperations.Tokenize(content, tokenizerConfig))
                    {
                        counter.Add(word);
                    }
                }
                keywordsNew = counter.GetMostFreqObjs(keywordNum);
                #endregion

                var scoredDocsNew = LuceneOperations.Search(searcher, searchfield, keywordsNew, max_doc_num);
                #region Test whether exit
                int repeatNum = 0;
                var docIDs    = new HashSet <int>();
                foreach (var scoredDoc in scoredDocs)
                {
                    docIDs.Add(scoredDoc.doc);
                }

                foreach (var scoredDocNew in scoredDocsNew)
                {
                    if (docIDs.Contains(scoredDocNew.doc))
                    {
                        repeatNum++;
                    }
                }

                bContinue = (double)repeatNum / scoredDocs.Length < threshold;
                #endregion

                Console.WriteLine(repeatNum + "  " + scoredDocsNew.Length);

                keywords   = keywordsNew;
                scoredDocs = scoredDocsNew;

                Console.WriteLine(StringOperations.GetMergedString(keywords));
            }

            max_doc_num = (int)(saveDocRatio * searcher.GetIndexReader().NumDocs());
            scoredDocs  = LuceneOperations.Search(searcher, searchfield, keywords, max_doc_num);
            var writer = LuceneOperations.GetIndexWriter(outputpath);
            foreach (var scoredDoc in scoredDocs)
            {
                Document doc = searcher.Doc(scoredDoc.doc);
                writer.AddDocument(doc);
            }
            writer.Optimize();
            writer.Close();

            if (isPrintRemovedDocuments)
            {
                var sw             = new StreamWriter(outputpath + "removeDocuments.txt");
                var selectedDocIDs = new HashSet <int>();
                foreach (var scoredDoc in scoredDocs)
                {
                    selectedDocIDs.Add(scoredDoc.doc);
                }

                var reader = searcher.GetIndexReader();
                for (int iDoc = 0; iDoc < reader.NumDocs(); iDoc++)
                {
                    if (!selectedDocIDs.Contains(iDoc))
                    {
                        sw.WriteLine(LuceneOperations.GetDocumentString(reader.Document(iDoc)));
                    }
                }
                reader.Close();
                sw.Flush();
                sw.Close();
            }

            searcher.Close();

            Console.WriteLine("Done");
            Console.ReadKey();
        }