public static void Train(IBMModel1 model, IEnumerable <SimpleTrainingRecord> training_corpus)
{
foreach (SimpleTrainingRecord rec in training_corpus)
{
string[] input_lang = rec.InputLang;
string[] output_lang = rec.OutputLang;
int[] a = rec.Alignment;
int m_input_len = input_lang.Length;
int l_output_len = output_lang.Length;
Debug.Assert(m_input_len == a.Length);
for (int j = 0; j < m_input_len; ++j)
{
int a_j = a[j];
string word_input = input_lang[j];
string word_output = output_lang[a_j];
double count_input_output = model.TranslationMap.GetCountOfInputWordAndOutputWord(word_input, word_output);
double count_output = model.TranslationMap.GetCountOfOutputWord(word_output);
model.TranslationMap.SetCountOfInputWordAndOutputWord(word_input, word_output, count_input_output + 1);
model.TranslationMap.SetCountOfOutputWord(word_output, count_output + 1);
model.TranslationMap.UpdateProbabilityInputWordGivenOutputWord(word_input, word_output);
}
}
}
public static void Initialize(IBMModel1 model, IEnumerable <EMTrainingRecord> training_corpus)
{
foreach (EMTrainingRecord rec in training_corpus)
{
string[] input_lang = rec.InputLang;
string[] output_lang = rec.OutputLang;
int m_input_len = input_lang.Length;
int l_output_len = output_lang.Length;
for (int j = 0; j < m_input_len; ++j)
{
for (int a_j = 0; a_j < l_output_len; ++a_j)
{
string word_input = input_lang[j];
string word_output = output_lang[a_j];
double count_input_output = model.TranslationMap.GetCountOfInputWordAndOutputWord(word_input, word_output);
double count_output = model.TranslationMap.GetCountOfOutputWord(word_output);
model.TranslationMap.SetProbabilityInputWordGivenOutputWord(word_input, word_output, mRandom.NextDouble());
}
}
}
}
public static void Train(IBMModel1 model, IEnumerable <EMTrainingRecord> training_corpus, int maxIterations)
{
for (int iteration = 0; iteration < maxIterations; ++iteration)
{
foreach (EMTrainingRecord rec in training_corpus)
{
string[] input_lang = rec.InputLang;
string[] output_lang = rec.OutputLang;
int m_input_len = input_lang.Length;
int l_output_len = output_lang.Length;
double[][] delta = new double[m_input_len][];
double sum = 0;
for (int j = 0; j < m_input_len; ++j)
{
delta[j] = new double[l_output_len];
string word_input = input_lang[j];
for (int a_j = 0; a_j < l_output_len; ++a_j)
{
string word_output = output_lang[a_j];
double t = model.TranslationMap.GetProbabilityInputWordGivenOutputWord(word_input, word_output);
double deltaVal = t;
delta[j][a_j] = deltaVal;
sum += deltaVal;
}
}
for (int j = 0; j < m_input_len; ++j)
{
for (int a_j = 0; a_j < l_output_len; ++a_j)
{
delta[j][a_j] /= sum;
}
}
for (int j = 0; j < m_input_len; ++j)
{
for (int a_j = 0; a_j < l_output_len; ++a_j)
{
double deltaVal = delta[j][a_j];
string word_input = input_lang[j];
string word_output = output_lang[a_j];
double count_input_output = model.TranslationMap.GetCountOfInputWordAndOutputWord(word_input, word_output);
double count_output = model.TranslationMap.GetCountOfOutputWord(word_output);
model.TranslationMap.SetCountOfInputWordAndOutputWord(word_input, word_output, count_input_output + deltaVal);
model.TranslationMap.SetCountOfOutputWord(word_output, count_output + deltaVal);
model.TranslationMap.UpdateProbabilityInputWordGivenOutputWord(word_input, word_output);
}
}
}
}
}
public void RunSimpleTraining()
{
IBMModel1.Helpers.IBMModel1 model = new IBMModel1.Helpers.IBMModel1();
List <SimpleTrainingRecord> training_corpus = new List <SimpleTrainingRecord>();
EnglishTokenizer tokenizer_output = new EnglishTokenizer();
FrenchTokenizer tokenizer_input = new FrenchTokenizer();
SimpleTrainingMethod.Train(model, training_corpus);
string sentence_input = "la maison bleue";
string sentence_output = "the blue house";
string[] input_lang = tokenizer_input.Tokenize(sentence_input);
string[] output_lang = tokenizer_output.Tokenize(sentence_output);
int[] alignment = model.GetAlignment(input_lang, output_lang);
Dictionary <int, string> output_mapping = new Dictionary <int, string>();
int m_input_len = input_lang.Length;
string output_word = "";
int ia = 1; //adding
for (int j = 0; j < m_input_len; ++j)
{
int a_j = alignment[j] + ia;
output_word = output_lang[a_j];
output_mapping[a_j] = output_word;
ia++;
}
List <int> output_sentence_index_list = output_mapping.Keys.ToList();
output_sentence_index_list.Sort();
string[] predicted_output_lang = new string[output_sentence_index_list.Count];
for (int i = 0; i < predicted_output_lang.Length; ++i)
{
predicted_output_lang[i] = output_mapping[output_sentence_index_list[i]];
}
Console.WriteLine("Original French Sentence: {0}", sentence_input);
Console.WriteLine("Predicted English Translation: {0}", string.Join(" ", predicted_output_lang));
Console.ReadLine();
}