/// <summary>
/// Determines whether [the specified token] [is a stop word].
/// </summary>
/// <param name="token">The token.</param>
/// <param name="language">The language.</param>
/// <returns><c>true</c> if [the specified token] [is a stop word]; otherwise, <c>false</c>.</returns>
public bool IsStopWord(string token, StopWordsLanguage language)
{
if (string.IsNullOrEmpty(token) || !StopWordsLanguages.TryGetValue(language, out var StopWords))
{
return(false);
}
return(StopWords.IsStopWord(token));
}
public static void CalculateTFIDF()
{
string db_path = @"C:\Users\Administrator\Documents\stackoverflow\WORDS_DATA";
string interm_path = @"C:\Users\Administrator\Documents\stackoverflow\INTERM_DATA";
Db db_words = new Db(db_path);
Db db_post = new Db(interm_path);
int step = 10000;
int start = db_post.Table <WholePost>().OrderBy(f => f.Id).Take(1).Select(f => new { f.Id }).Select(f => f.Id).First();
int end = db_post.Table <WholePost>().OrderByDescending(f => f.Id).Take(1).Select(f => new { f.Id }).Select(f => f.Id).First();
var list = new List <WholePost>();
int print_counter = 0;
var dic = new Dictionary <string, int>();
for (int i = start; ; i += step, print_counter += step)
{
list = db_post.Table <WholePost>().BetweenInt(f => f.Id, i, i + step, BetweenBoundaries.FromInclusiveToExclusive).SelectEntity();
if (!list.Any())
{
if (i < end)
{
continue;
}
else
{
break;
}
}
if (print_counter % 50000 == 0)
{
Console.WriteLine("phase 1: " + print_counter);
}
int total = 0;
foreach (var p in list)
{
var text = p.Text;
var words = new List <string>();
foreach (var word in text.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries))
{
var w = word.ToLower().Trim(" .,?()!:;'\"[]".ToCharArray());
if (string.IsNullOrEmpty(w) || StopWords.IsStopWord(w) || w.Length > 10 || w.Count(f => NonReadable.Contains(f)) > 3 ||
(w.Count(f => NonReadable.Contains(f)) / (double)w.Length > 0.3 && w.Length > 4))
{
continue;
}
words.Add(w);
}
foreach (var w in words.GroupBy(f => f))
{
if (dic.ContainsKey(w.Key))
{
dic[w.Key]++;
}
else
{
dic[w.Key] = 1;
}
total++;
}
}
}
dic = dic.Where(f => f.Value > 40).ToDictionary(f => f.Key, f => f.Value);
//calculate tf-idf
var saved_words = new HashSet <string>();
int total_docs = db_post.Table <WholePost>().Count();
step = 10000;
print_counter = 0;
int saved_count = 0;
int not_saved_count = 0;
for (int i = start; ; i += step, print_counter += step)
{
list = db_post.Table <WholePost>().BetweenInt(f => f.Id, i, i + step, BetweenBoundaries.FromInclusiveToExclusive).SelectEntity();
if (!list.Any())
{
if (i < end)
{
continue;
}
else
{
break;
}
}
if (print_counter % 50000 == 0)
{
Console.WriteLine("phase 2: " + print_counter);
}
var saved = new List <WordTfIdf>();
foreach (var p in list)
{
var text = p.Text;
var words = new List <string>();
foreach (var word in text.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries))
{
var w = word.ToLower().Trim(" .,?()!:;'\"[]".ToCharArray());
if (string.IsNullOrEmpty(w) || StopWords.IsStopWord(w) || w.Length > 13 || w.Count(f => NonReadable.Contains(f)) > 3 ||
(w.Count(f => NonReadable.Contains(f)) / (double)w.Length > 0.3 && w.Length > 4))
{
continue;
}
words.Add(w);
}
foreach (var w in words.GroupBy(f => f))
{
if (!dic.ContainsKey(w.Key))
{
continue;
}
double tf = w.Count() < Math.E ? w.Count() : (Math.E + Math.Log(w.Count()));
int wdocs = dic[w.Key];
double tmp = total_docs / (double)wdocs;
double idf = tmp < Math.E ? tmp : (Math.E + Math.Log(tmp));
var tfidf = new WordTfIdf()
{
QuestionId = p.Id,
Word = w.Key,
TfIdf = tf * idf
};
if (tfidf.TfIdf > 17)
{
saved.Add(tfidf);
if (saved.Count() == 5000)
{
db_words.Table <WordTfIdf>().SaveBatch(saved);
saved = new List <WordTfIdf>();
}
saved_words.Add(tfidf.Word);
saved_count++;
}
else
{
not_saved_count++;
}
}
}
db_words.Table <WordTfIdf>().SaveBatch(saved);
saved = new List <WordTfIdf>();
}
//convenient representation
var saved_data = new List <WordTfIdfData>();
foreach (var w in saved_words)
{
var l = db_words.Table <WordTfIdf>().Where(f => f.Word == w).SelectEntity();
var data = Utils.TfIdfToData(l);
var nd = new WordTfIdfData()
{
Word = w,
Data = data
};
saved_data.Add(nd);
if (saved_data.Count() == 50)
{
db_words.Table <WordTfIdfData>().SaveBatch(saved_data);
saved_data = new List <WordTfIdfData>();
}
}
db_words.Table <WordTfIdfData>().SaveBatch(saved_data);
saved_data = new List <WordTfIdfData>();
Console.WriteLine("Done. Saved: " + saved_count + " not saved: " + not_saved_count);
db_words.Dispose();
db_post.Dispose();
}
public string SearchNode(string data_json)
{
var data = JsonConvert.DeserializeObject <SearchData>(data_json);
var words = data.Query.Trim().Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries).ToList();
var cw = new List <string>();
foreach (var w in words)
{
if (!StopWords.IsStopWord(w))
{
cw.Add(w);
}
}
data.Query = cw.Distinct().Aggregate((a, b) => a + " " + b);
if (string.IsNullOrEmpty(data.Query))
{
data.Links = new List <Models.Result>();
return(JsonConvert.SerializeObject(data));
}
if (data.TitleSearch)
{
Stopwatch sp = new Stopwatch();
sp.Start();
var tres = SearchApi.SearchTitles(data.Query);
var title_links = tres.Select(f => new WebMvc.Models.Result()
{
IsMeta = true,
Description = GetWords(f.Fragment, words),
Title = GetWords(f.Title, words),
Url = "http://stackoverflow.com/questions/" + f.Id,
Id = f.Id,
Score = f.Score
})
.ToList();
data.Links = title_links;
sp.Stop();
data.NodeTimeInMs = sp.ElapsedMilliseconds;
}
else
{
Stopwatch sp = new Stopwatch();
sp.Start();
var mres = SearchApi.SearchMain(data.Query);
var main_links = mres.Select(z => new WebMvc.Models.Result()
{
IsMeta = false,
Description = GetWords(z.Fragment, words),
Title = GetWords(z.Title, words),
Score = z.Score,
Url = "http://stackoverflow.com/questions/" + z.Id,
Id = z.Id
})
.ToList();
data.Links = main_links;
sp.Stop();
data.NodeTimeInMs = sp.ElapsedMilliseconds;
}
return(JsonConvert.SerializeObject(data));
}
