public double GetProbabilityOfSpam(Stream mimeMessageStream)
{
var rawWords = wordsExtractor.ExtractWords(mimeMessageStream);
var preprocessedWords = wordsPreprocessor.PreprocessWords(rawWords);
var expDegree = preprocessedWords
.Where(probabilityProvider.HasProbability)
.Select(word => probabilityProvider.GetProbabilityOf(MsgClass.Spam, word))
.Sum(spamGivenWordPr => Math.Log(1 - spamGivenWordPr) - Math.Log(spamGivenWordPr));
var spamGivenAllWordsProbability = 1 / (Math.Exp(expDegree) + 1);
return(spamGivenAllWordsProbability);
}
private static Dictionary <string, int> CalculateWordsCount(IEnumerable <FileInfo> msgFiles, IWordsExtractor wordsExtractor, IWordsPreprocessor wordsPreprocessor)
{
var wordToCountMessagesWithThisWord = new Dictionary <string, int>();
foreach (var messageFile in msgFiles)
{
var rawWords = wordsExtractor.ExtractWords(messageFile.OpenRead());
var preprocessedWords = wordsPreprocessor.PreprocessWords(rawWords);
foreach (var word in preprocessedWords.Distinct())
{
if (!wordToCountMessagesWithThisWord.ContainsKey(word))
{
wordToCountMessagesWithThisWord[word] = 0;
}
wordToCountMessagesWithThisWord[word]++;
}
}
return(wordToCountMessagesWithThisWord);
}