Merge remote-tracking branch 'upstream/master'

17 files changed, 473 insertions, 246 deletions

diff --git a/extractor/alignment.cc b/extractor/alignment.cc
index b187c03a..2278c825 100644
--- a/extractor/alignment.cc
+++ b/extractor/alignment.cc
@@ -23,8 +23,8 @@ Alignment::Alignment(const string& filename) {
     boost::split(items, line, boost::is_any_of(" -"));
     vector<pair<int, int>> alignment;
     alignment.reserve(items.size() / 2);
-    for (size_t i = 0; i < items.size(); i += 2) {
-      alignment.push_back(make_pair(stoi(items[i]), stoi(items[i + 1])));
+    for (size_t i = 1; i < items.size(); i += 2) {
+      alignment.push_back(make_pair(stoi(items[i - 1]), stoi(items[i])));
     }
     alignments.push_back(alignment);
   }
@@ -39,15 +39,8 @@ vector<pair<int, int>> Alignment::GetLinks(int sentence_index) const {
   return alignments[sentence_index];
 }
 
-void Alignment::WriteBinary(const fs::path& filepath) {
-  FILE* file = fopen(filepath.string().c_str(), "w");
-  int size = alignments.size();
-  fwrite(&size, sizeof(int), 1, file);
-  for (vector<pair<int, int>> alignment: alignments) {
-    size = alignment.size();
-    fwrite(&size, sizeof(int), 1, file);
-    fwrite(alignment.data(), sizeof(pair<int, int>), size, file);
-  }
+bool Alignment::operator==(const Alignment& other) const {
+  return alignments == other.alignments;
 }
 
 } // namespace extractor
diff --git a/extractor/alignment.h b/extractor/alignment.h
index 4596f92b..dc5a8b55 100644
--- a/extractor/alignment.h
+++ b/extractor/alignment.h
@@ -5,6 +5,10 @@
 #include <vector>
 
 #include <boost/filesystem.hpp>
+#include <boost/serialization/serialization.hpp>
+#include <boost/serialization/split_member.hpp>
+#include <boost/serialization/utility.hpp>
+#include <boost/serialization/vector.hpp>
 
 namespace fs = boost::filesystem;
 using namespace std;
@@ -19,18 +23,23 @@ class Alignment {
   // Reads alignment from text file.
   Alignment(const string& filename);
 
+  // Creates empty alignment.
+  Alignment();
+
   // Returns the alignment for a given sentence.
   virtual vector<pair<int, int>> GetLinks(int sentence_index) const;
 
-  // Writes alignment to file in binary format.
-  void WriteBinary(const fs::path& filepath);
-
   virtual ~Alignment();
 
- protected:
-  Alignment();
+  bool operator==(const Alignment& alignment) const;
 
  private:
+  friend class boost::serialization::access;
+
+  template<class Archive> void serialize(Archive& ar, unsigned int) {
+    ar & alignments;
+  }
+
   vector<vector<pair<int, int>>> alignments;
 };
 
diff --git a/extractor/alignment_test.cc b/extractor/alignment_test.cc
index 43c37ebd..1b8ff531 100644
--- a/extractor/alignment_test.cc
+++ b/extractor/alignment_test.cc
@@ -1,12 +1,16 @@
 #include <gtest/gtest.h>
 
-#include <memory>
+#include <sstream>
 #include <string>
 
+#include <boost/archive/binary_iarchive.hpp>
+#include <boost/archive/binary_oarchive.hpp>
+
 #include "alignment.h"
 
 using namespace std;
 using namespace ::testing;
+namespace ar = boost::archive;
 
 namespace extractor {
 namespace {
@@ -14,19 +18,31 @@ namespace {
 class AlignmentTest : public Test {
  protected:
   virtual void SetUp() {
-    alignment = make_shared<Alignment>("sample_alignment.txt");
+    alignment = Alignment("sample_alignment.txt");
   }
 
-  shared_ptr<Alignment> alignment;
+  Alignment alignment;
 };
 
 TEST_F(AlignmentTest, TestGetLinks) {
   vector<pair<int, int>> expected_links = {
     make_pair(0, 0), make_pair(1, 1), make_pair(2, 2)
   };
-  EXPECT_EQ(expected_links, alignment->GetLinks(0));
+  EXPECT_EQ(expected_links, alignment.GetLinks(0));
   expected_links = {make_pair(1, 0), make_pair(2, 1)};
-  EXPECT_EQ(expected_links, alignment->GetLinks(1));
+  EXPECT_EQ(expected_links, alignment.GetLinks(1));
+}
+
+TEST_F(AlignmentTest, TestSerialization) {
+  stringstream stream(ios_base::binary | ios_base::out | ios_base::in);
+  ar::binary_oarchive output_stream(stream, ar::no_header);
+  output_stream << alignment;
+
+  Alignment alignment_copy;
+  ar::binary_iarchive input_stream(stream, ar::no_header);
+  input_stream >> alignment_copy;
+
+  EXPECT_EQ(alignment, alignment_copy);
 }
 
 } // namespace
diff --git a/extractor/compile.cc b/extractor/compile.cc
index a9ae2cef..65fdd509 100644
--- a/extractor/compile.cc
+++ b/extractor/compile.cc
@@ -1,6 +1,8 @@
+#include <fstream>
 #include <iostream>
 #include <string>
 
+#include <boost/archive/binary_oarchive.hpp>
 #include <boost/filesystem.hpp>
 #include <boost/program_options.hpp>
 #include <boost/program_options/variables_map.hpp>
@@ -9,8 +11,10 @@
 #include "data_array.h"
 #include "precomputation.h"
 #include "suffix_array.h"
+#include "time_util.h"
 #include "translation_table.h"
 
+namespace ar = boost::archive;
 namespace fs = boost::filesystem;
 namespace po = boost::program_options;
 using namespace std;
@@ -58,11 +62,14 @@ int main(int argc, char** argv) {
     return 1;
   }
 
-  fs::path output_dir(vm["output"].as<string>().c_str());
+  fs::path output_dir(vm["output"].as<string>());
   if (!fs::exists(output_dir)) {
     fs::create_directory(output_dir);
   }
 
+  // Reading source and target data.
+  Clock::time_point start_time = Clock::now();
+  cerr << "Reading source and target data..." << endl;
   shared_ptr<DataArray> source_data_array, target_data_array;
   if (vm.count("bitext")) {
     source_data_array = make_shared<DataArray>(
@@ -73,15 +80,53 @@ int main(int argc, char** argv) {
     source_data_array = make_shared<DataArray>(vm["source"].as<string>());
     target_data_array = make_shared<DataArray>(vm["target"].as<string>());
   }
+
+  Clock::time_point start_write = Clock::now();
+  ofstream target_fstream((output_dir / fs::path("target.bin")).string());
+  ar::binary_oarchive target_stream(target_fstream);
+  target_stream << *target_data_array;
+  Clock::time_point stop_write = Clock::now();
+  double write_duration = GetDuration(start_write, stop_write);
+
+  Clock::time_point stop_time = Clock::now();
+  cerr << "Reading data took " << GetDuration(start_time, stop_time)
+       << " seconds" << endl;
+
+  // Constructing and compiling the suffix array.
+  start_time = Clock::now();
+  cerr << "Constructing source suffix array..." << endl;
   shared_ptr<SuffixArray> source_suffix_array =
       make_shared<SuffixArray>(source_data_array);
-  source_suffix_array->WriteBinary(output_dir / fs::path("f.bin"));
-  target_data_array->WriteBinary(output_dir / fs::path("e.bin"));
 
+  start_write = Clock::now();
+  ofstream source_fstream((output_dir / fs::path("source.bin")).string());
+  ar::binary_oarchive output_stream(source_fstream);
+  output_stream << *source_suffix_array;
+  stop_write = Clock::now();
+  write_duration += GetDuration(start_write, stop_write);
+
+  cerr << "Constructing suffix array took "
+       << GetDuration(start_time, stop_time) << " seconds" << endl;
+
+  // Reading alignment.
+  start_time = Clock::now();
+  cerr << "Reading alignment..." << endl;
   shared_ptr<Alignment> alignment =
       make_shared<Alignment>(vm["alignment"].as<string>());
-  alignment->WriteBinary(output_dir / fs::path("a.bin"));
 
+  start_write = Clock::now();
+  ofstream alignment_fstream((output_dir / fs::path("alignment.bin")).string());
+  ar::binary_oarchive alignment_stream(alignment_fstream);
+  alignment_stream << *alignment;
+  stop_write = Clock::now();
+  write_duration += GetDuration(start_write, stop_write);
+
+  stop_time = Clock::now();
+  cerr << "Reading alignment took "
+       << GetDuration(start_time, stop_time) << " seconds" << endl;
+
+  start_time = Clock::now();
+  cerr << "Precomputing collocations..." << endl;
   Precomputation precomputation(
       source_suffix_array,
       vm["frequent"].as<int>(),
@@ -91,10 +136,35 @@ int main(int argc, char** argv) {
       vm["min_gap_size"].as<int>(),
       vm["max_phrase_len"].as<int>(),
       vm["min_frequency"].as<int>());
-  precomputation.WriteBinary(output_dir / fs::path("precompute.bin"));
 
+  start_write = Clock::now();
+  ofstream precomp_fstream((output_dir / fs::path("precomp.bin")).string());
+  ar::binary_oarchive precomp_stream(precomp_fstream);
+  precomp_stream << precomputation;
+  stop_write = Clock::now();
+  write_duration += GetDuration(start_write, stop_write);
+
+  stop_time = Clock::now();
+  cerr << "Precomputing collocations took "
+       << GetDuration(start_time, stop_time) << " seconds" << endl;
+
+  start_time = Clock::now();
+  cerr << "Precomputing conditional probabilities..." << endl;
   TranslationTable table(source_data_array, target_data_array, alignment);
-  table.WriteBinary(output_dir / fs::path("lex.bin"));
+
+  start_write = Clock::now();
+  ofstream table_fstream((output_dir / fs::path("bilex.bin")).string());
+  ar::binary_oarchive table_stream(table_fstream);
+  table_stream << table;
+  stop_write = Clock::now();
+  write_duration += GetDuration(start_write, stop_write);
+
+  stop_time = Clock::now();
+  cerr << "Precomputing conditional probabilities took "
+       << GetDuration(start_time, stop_time) << " seconds" << endl;
+
+  cerr << "Total time spent writing: " << write_duration
+       << " seconds" << endl;
 
   return 0;
 }
diff --git a/extractor/data_array.cc b/extractor/data_array.cc
index 203fe219..2e4bdafb 100644
--- a/extractor/data_array.cc
+++ b/extractor/data_array.cc
@@ -118,33 +118,6 @@ int DataArray::GetSentenceId(int position) const {
   return sentence_id[position];
 }
 
-void DataArray::WriteBinary(const fs::path& filepath) const {
-  std::cerr << "File: " << filepath.string() << std::endl;
-  WriteBinary(fopen(filepath.string().c_str(), "w"));
-}
-
-void DataArray::WriteBinary(FILE* file) const {
-  int size = id2word.size();
-  fwrite(&size, sizeof(int), 1, file);
-  for (string word: id2word) {
-    size = word.size();
-    fwrite(&size, sizeof(int), 1, file);
-    fwrite(word.data(), sizeof(char), size, file);
-  }
-
-  size = data.size();
-  fwrite(&size, sizeof(int), 1, file);
-  fwrite(data.data(), sizeof(int), size, file);
-
-  size = sentence_id.size();
-  fwrite(&size, sizeof(int), 1, file);
-  fwrite(sentence_id.data(), sizeof(int), size, file);
-
-  size = sentence_start.size();
-  fwrite(&size, sizeof(int), 1, file);
-  fwrite(sentence_start.data(), sizeof(int), 1, file);
-}
-
 bool DataArray::HasWord(const string& word) const {
   return word2id.count(word);
 }
@@ -158,4 +131,10 @@ string DataArray::GetWord(int word_id) const {
   return id2word[word_id];
 }
 
+bool DataArray::operator==(const DataArray& other) const {
+  return word2id == other.word2id && id2word == other.id2word &&
+         data == other.data && sentence_start == other.sentence_start &&
+         sentence_id == other.sentence_id;
+}
+
 } // namespace extractor
diff --git a/extractor/data_array.h b/extractor/data_array.h
index 978a6931..2be6a09c 100644
--- a/extractor/data_array.h
+++ b/extractor/data_array.h
@@ -6,6 +6,10 @@
 #include <vector>
 
 #include <boost/filesystem.hpp>
+#include <boost/serialization/serialization.hpp>
+#include <boost/serialization/split_member.hpp>
+#include <boost/serialization/string.hpp>
+#include <boost/serialization/vector.hpp>
 
 namespace fs = boost::filesystem;
 using namespace std;
@@ -43,6 +47,9 @@ class DataArray {
   // Reads data array from bitext file where the sentences are separated by |||.
   DataArray(const string& filename, const Side& side);
 
+  // Creates empty data array.
+  DataArray();
+
   virtual ~DataArray();
 
   // Returns a vector containing the word ids.
@@ -82,14 +89,7 @@ class DataArray {
   // Returns the number of the sentence containing the given position.
   virtual int GetSentenceId(int position) const;
 
-  // Writes data array to file in binary format.
-  void WriteBinary(const fs::path& filepath) const;
-
-  // Writes data array to file in binary format.
-  void WriteBinary(FILE* file) const;
-
- protected:
-  DataArray();
+  bool operator==(const DataArray& other) const;
 
  private:
   // Sets up specific constants.
@@ -98,6 +98,28 @@ class DataArray {
   // Constructs the data array.
   void CreateDataArray(const vector<string>& lines);
 
+  friend class boost::serialization::access;
+
+  template<class Archive> void save(Archive& ar, unsigned int) const {
+    ar << id2word;
+    ar << data;
+    ar << sentence_id;
+    ar << sentence_start;
+  }
+
+  template<class Archive> void load(Archive& ar, unsigned int) {
+    ar >> id2word;
+    for (size_t i = 0; i < id2word.size(); ++i) {
+      word2id[id2word[i]] = i;
+    }
+
+    ar >> data;
+    ar >> sentence_id;
+    ar >> sentence_start;
+  }
+
+  BOOST_SERIALIZATION_SPLIT_MEMBER();
+
   unordered_map<string, int> word2id;
   vector<string> id2word;
   vector<int> data;
diff --git a/extractor/data_array_test.cc b/extractor/data_array_test.cc
index 71175fda..6c329e34 100644
--- a/extractor/data_array_test.cc
+++ b/extractor/data_array_test.cc
@@ -1,8 +1,11 @@
 #include <gtest/gtest.h>
 
 #include <memory>
+#include <sstream>
 #include <string>
 
+#include <boost/archive/binary_iarchive.hpp>
+#include <boost/archive/binary_oarchive.hpp>
 #include <boost/filesystem.hpp>
 
 #include "data_array.h"
@@ -10,6 +13,7 @@
 using namespace std;
 using namespace ::testing;
 namespace fs = boost::filesystem;
+namespace ar = boost::archive;
 
 namespace extractor {
 namespace {
@@ -18,12 +22,12 @@ class DataArrayTest : public Test {
  protected:
   virtual void SetUp() {
     string sample_test_file("sample_bitext.txt");
-    source_data = make_shared<DataArray>(sample_test_file, SOURCE);
-    target_data = make_shared<DataArray>(sample_test_file, TARGET);
+    source_data = DataArray(sample_test_file, SOURCE);
+    target_data = DataArray(sample_test_file, TARGET);
   }
 
-  shared_ptr<DataArray> source_data;
-  shared_ptr<DataArray> target_data;
+  DataArray source_data;
+  DataArray target_data;
 };
 
 TEST_F(DataArrayTest, TestGetData) {
@@ -32,11 +36,11 @@ TEST_F(DataArrayTest, TestGetData) {
       "ana", "are", "mere", ".", "__END_OF_LINE__",
       "ana", "bea", "mult", "lapte", ".", "__END_OF_LINE__"
   };
-  EXPECT_EQ(expected_source_data, source_data->GetData());
-  EXPECT_EQ(expected_source_data.size(), source_data->GetSize());
+  EXPECT_EQ(expected_source_data, source_data.GetData());
+  EXPECT_EQ(expected_source_data.size(), source_data.GetSize());
   for (size_t i = 0; i < expected_source_data.size(); ++i) {
-    EXPECT_EQ(expected_source_data[i], source_data->AtIndex(i));
-    EXPECT_EQ(expected_source_words[i], source_data->GetWordAtIndex(i));
+    EXPECT_EQ(expected_source_data[i], source_data.AtIndex(i));
+    EXPECT_EQ(expected_source_words[i], source_data.GetWordAtIndex(i));
   }
 
   vector<int> expected_target_data = {2, 3, 4, 5, 1, 2, 6, 7, 8, 9, 10, 5, 1};
@@ -44,55 +48,68 @@ TEST_F(DataArrayTest, TestGetData) {
       "anna", "has", "apples", ".", "__END_OF_LINE__",
       "anna", "drinks", "a", "lot", "of", "milk", ".", "__END_OF_LINE__"
   };
-  EXPECT_EQ(expected_target_data, target_data->GetData());
-  EXPECT_EQ(expected_target_data.size(), target_data->GetSize());
+  EXPECT_EQ(expected_target_data, target_data.GetData());
+  EXPECT_EQ(expected_target_data.size(), target_data.GetSize());
   for (size_t i = 0; i < expected_target_data.size(); ++i) {
-    EXPECT_EQ(expected_target_data[i], target_data->AtIndex(i));
-    EXPECT_EQ(expected_target_words[i], target_data->GetWordAtIndex(i));
+    EXPECT_EQ(expected_target_data[i], target_data.AtIndex(i));
+    EXPECT_EQ(expected_target_words[i], target_data.GetWordAtIndex(i));
   }
 }
 
 TEST_F(DataArrayTest, TestVocabulary) {
-  EXPECT_EQ(9, source_data->GetVocabularySize());
-  EXPECT_TRUE(source_data->HasWord("mere"));
-  EXPECT_EQ(4, source_data->GetWordId("mere"));
-  EXPECT_EQ("mere", source_data->GetWord(4));
-  EXPECT_FALSE(source_data->HasWord("banane"));
-
-  EXPECT_EQ(11, target_data->GetVocabularySize());
-  EXPECT_TRUE(target_data->HasWord("apples"));
-  EXPECT_EQ(4, target_data->GetWordId("apples"));
-  EXPECT_EQ("apples", target_data->GetWord(4));
-  EXPECT_FALSE(target_data->HasWord("bananas"));
+  EXPECT_EQ(9, source_data.GetVocabularySize());
+  EXPECT_TRUE(source_data.HasWord("mere"));
+  EXPECT_EQ(4, source_data.GetWordId("mere"));
+  EXPECT_EQ("mere", source_data.GetWord(4));
+  EXPECT_FALSE(source_data.HasWord("banane"));
+
+  EXPECT_EQ(11, target_data.GetVocabularySize());
+  EXPECT_TRUE(target_data.HasWord("apples"));
+  EXPECT_EQ(4, target_data.GetWordId("apples"));
+  EXPECT_EQ("apples", target_data.GetWord(4));
+  EXPECT_FALSE(target_data.HasWord("bananas"));
 }
 
 TEST_F(DataArrayTest, TestSentenceData) {
-  EXPECT_EQ(2, source_data->GetNumSentences());
-  EXPECT_EQ(0, source_data->GetSentenceStart(0));
-  EXPECT_EQ(5, source_data->GetSentenceStart(1));
-  EXPECT_EQ(11, source_data->GetSentenceStart(2));
+  EXPECT_EQ(2, source_data.GetNumSentences());
+  EXPECT_EQ(0, source_data.GetSentenceStart(0));
+  EXPECT_EQ(5, source_data.GetSentenceStart(1));
+  EXPECT_EQ(11, source_data.GetSentenceStart(2));
 
-  EXPECT_EQ(4, source_data->GetSentenceLength(0));
-  EXPECT_EQ(5, source_data->GetSentenceLength(1));
+  EXPECT_EQ(4, source_data.GetSentenceLength(0));
+  EXPECT_EQ(5, source_data.GetSentenceLength(1));
 
   vector<int> expected_source_ids = {0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1};
   for (size_t i = 0; i < expected_source_ids.size(); ++i) {
-    EXPECT_EQ(expected_source_ids[i], source_data->GetSentenceId(i));
+    EXPECT_EQ(expected_source_ids[i], source_data.GetSentenceId(i));
   }
 
-  EXPECT_EQ(2, target_data->GetNumSentences());
-  EXPECT_EQ(0, target_data->GetSentenceStart(0));
-  EXPECT_EQ(5, target_data->GetSentenceStart(1));
-  EXPECT_EQ(13, target_data->GetSentenceStart(2));
+  EXPECT_EQ(2, target_data.GetNumSentences());
+  EXPECT_EQ(0, target_data.GetSentenceStart(0));
+  EXPECT_EQ(5, target_data.GetSentenceStart(1));
+  EXPECT_EQ(13, target_data.GetSentenceStart(2));
 
-  EXPECT_EQ(4, target_data->GetSentenceLength(0));
-  EXPECT_EQ(7, target_data->GetSentenceLength(1));
+  EXPECT_EQ(4, target_data.GetSentenceLength(0));
+  EXPECT_EQ(7, target_data.GetSentenceLength(1));
 
   vector<int> expected_target_ids = {0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1};
   for (size_t i = 0; i < expected_target_ids.size(); ++i) {
-    EXPECT_EQ(expected_target_ids[i], target_data->GetSentenceId(i));
+    EXPECT_EQ(expected_target_ids[i], target_data.GetSentenceId(i));
   }
 }
 
+TEST_F(DataArrayTest, TestSerialization) {
+  stringstream stream(ios_base::binary | ios_base::out | ios_base::in);
+  ar::binary_oarchive output_stream(stream, ar::no_header);
+  output_stream << source_data << target_data;
+
+  DataArray source_copy, target_copy;
+  ar::binary_iarchive input_stream(stream, ar::no_header);
+  input_stream >> source_copy >> target_copy;
+
+  EXPECT_EQ(source_data, source_copy);
+  EXPECT_EQ(target_data, target_copy);
+}
+
 } // namespace
 } // namespace extractor
diff --git a/extractor/precomputation.cc b/extractor/precomputation.cc
index ee4ba42c..3b8aed69 100644
--- a/extractor/precomputation.cc
+++ b/extractor/precomputation.cc
@@ -165,25 +165,12 @@ void Precomputation::AddStartPositions(
   positions.push_back(pos3);
 }
 
-void Precomputation::WriteBinary(const fs::path& filepath) const {
-  FILE* file = fopen(filepath.string().c_str(), "w");
-
-  // TODO(pauldb): Refactor this code.
-  int size = collocations.size();
-  fwrite(&size, sizeof(int), 1, file);
-  for (auto entry: collocations) {
-    size = entry.first.size();
-    fwrite(&size, sizeof(int), 1, file);
-    fwrite(entry.first.data(), sizeof(int), size, file);
-
-    size = entry.second.size();
-    fwrite(&size, sizeof(int), 1, file);
-    fwrite(entry.second.data(), sizeof(int), size, file);
-  }
-}
-
 const Index& Precomputation::GetCollocations() const {
   return collocations;
 }
 
+bool Precomputation::operator==(const Precomputation& other) const {
+  return collocations == other.collocations;
+}
+
 } // namespace extractor
diff --git a/extractor/precomputation.h b/extractor/precomputation.h
index 3e792ac7..9f0c9424 100644
--- a/extractor/precomputation.h
+++ b/extractor/precomputation.h
@@ -9,6 +9,9 @@
 
 #include <boost/filesystem.hpp>
 #include <boost/functional/hash.hpp>
+#include <boost/serialization/serialization.hpp>
+#include <boost/serialization/utility.hpp>
+#include <boost/serialization/vector.hpp>
 
 namespace fs = boost::filesystem;
 using namespace std;
@@ -39,19 +42,19 @@ class Precomputation {
       int max_rule_symbols, int min_gap_size,
       int max_frequent_phrase_len, int min_frequency);
 
-  virtual ~Precomputation();
+  // Creates empty precomputation data structure.
+  Precomputation();
 
-  void WriteBinary(const fs::path& filepath) const;
+  virtual ~Precomputation();
 
   // Returns a reference to the index.
   virtual const Index& GetCollocations() const;
 
+  bool operator==(const Precomputation& other) const;
+
   static int FIRST_NONTERMINAL;
   static int SECOND_NONTERMINAL;
 
- protected:
-  Precomputation();
-
  private:
   // Finds the most frequent contiguous collocations.
   vector<vector<int>> FindMostFrequentPatterns(
@@ -72,6 +75,28 @@ class Precomputation {
   // Adds an occurrence of a ternary collocation.
   void AddStartPositions(vector<int>& positions, int pos1, int pos2, int pos3);
 
+  friend class boost::serialization::access;
+
+  template<class Archive> void save(Archive& ar, unsigned int) const {
+    int num_entries = collocations.size();
+    ar << num_entries;
+    for (pair<vector<int>, vector<int>> entry: collocations) {
+      ar << entry;
+    }
+  }
+
+  template<class Archive> void load(Archive& ar, unsigned int) {
+    int num_entries;
+    ar >> num_entries;
+    for (size_t i = 0; i < num_entries; ++i) {
+      pair<vector<int>, vector<int>> entry;
+      ar >> entry;
+      collocations.insert(entry);
+    }
+  }
+
+  BOOST_SERIALIZATION_SPLIT_MEMBER();
+
   Index collocations;
 };
 
diff --git a/extractor/precomputation_test.cc b/extractor/precomputation_test.cc
index 363febb7..e81ece5d 100644
--- a/extractor/precomputation_test.cc
+++ b/extractor/precomputation_test.cc
@@ -1,14 +1,19 @@
 #include <gtest/gtest.h>
 
 #include <memory>
+#include <sstream>
 #include <vector>
 
+#include <boost/archive/text_iarchive.hpp>
+#include <boost/archive/text_oarchive.hpp>
+
 #include "mocks/mock_data_array.h"
 #include "mocks/mock_suffix_array.h"
 #include "precomputation.h"
 
 using namespace std;
 using namespace ::testing;
+namespace ar = boost::archive;
 
 namespace extractor {
 namespace {
@@ -29,15 +34,17 @@ class PrecomputationTest : public Test {
                   GetSuffix(i)).WillRepeatedly(Return(suffixes[i]));
     }
     EXPECT_CALL(*suffix_array, BuildLCPArray()).WillRepeatedly(Return(lcp));
+
+    precomputation = Precomputation(suffix_array, 3, 3, 10, 5, 1, 4, 2);
   }
 
   vector<int> data;
   shared_ptr<MockDataArray> data_array;
   shared_ptr<MockSuffixArray> suffix_array;
+  Precomputation precomputation;
 };
 
 TEST_F(PrecomputationTest, TestCollocations) {
-  Precomputation precomputation(suffix_array, 3, 3, 10, 5, 1, 4, 2);
   Index collocations = precomputation.GetCollocations();
 
   vector<int> key = {2, 3, -1, 2};
@@ -101,6 +108,18 @@ TEST_F(PrecomputationTest, TestCollocations) {
   EXPECT_EQ(0, collocations.count(key));
 }
 
+TEST_F(PrecomputationTest, TestSerialization) {
+  stringstream stream(ios_base::out | ios_base::in);
+  ar::text_oarchive output_stream(stream, ar::no_header);
+  output_stream << precomputation;
+
+  Precomputation precomputation_copy;
+  ar::text_iarchive input_stream(stream, ar::no_header);
+  input_stream >> precomputation_copy;
+
+  EXPECT_EQ(precomputation, precomputation_copy);
+}
+
 } // namespace
 } // namespace extractor
 
diff --git a/extractor/run_extractor.cc b/extractor/run_extractor.cc
index 2fc6f724..8a9ca89d 100644
--- a/extractor/run_extractor.cc
+++ b/extractor/run_extractor.cc
@@ -42,11 +42,12 @@ fs::path GetGrammarFilePath(const fs::path& grammar_path, int file_number) {
 }
 
 int main(int argc, char** argv) {
-  int num_threads_default = 1;
-  #pragma omp parallel
-  num_threads_default = omp_get_num_threads();
-
   // Sets up the command line arguments map.
+  int max_threads = 1;
+  #pragma omp parallel
+  max_threads = omp_get_num_threads();
+  string threads_option = "Number of parallel threads for extraction "
+                          "(max=" + to_string(max_threads) + ")";
   po::options_description desc("Command line options");
   desc.add_options()
     ("help,h", "Show available options")
@@ -55,8 +56,7 @@ int main(int argc, char** argv) {
     ("bitext,b", po::value<string>(), "Parallel text (source ||| target)")
     ("alignment,a", po::value<string>()->required(), "Bitext word alignment")
     ("grammars,g", po::value<string>()->required(), "Grammars output path")
-    ("threads,t", po::value<int>()->default_value(num_threads_default),
-        "Number of parallel extractors")
+    ("threads,t", po::value<int>()->default_value(1), threads_option.c_str())
     ("frequent", po::value<int>()->default_value(100),
         "Number of precomputed frequent patterns")
     ("super_frequent", po::value<int>()->default_value(10),
@@ -97,7 +97,7 @@ int main(int argc, char** argv) {
   }
 
   int num_threads = vm["threads"].as<int>();
-  cout << "Grammar extraction will use " << num_threads << " threads." << endl;
+  cerr << "Grammar extraction will use " << num_threads << " threads." << endl;
 
   // Reads the parallel corpus.
   Clock::time_point preprocess_start_time = Clock::now();
@@ -118,17 +118,17 @@ int main(int argc, char** argv) {
        << " seconds" << endl;
 
   // Constructs the suffix array for the source data.
-  cerr << "Creating source suffix array..." << endl;
   start_time = Clock::now();
+  cerr << "Constructing source suffix array..." << endl;
   shared_ptr<SuffixArray> source_suffix_array =
       make_shared<SuffixArray>(source_data_array);
   stop_time = Clock::now();
-  cerr << "Creating suffix array took "
+  cerr << "Constructing suffix array took "
        << GetDuration(start_time, stop_time) << " seconds" << endl;
 
   // Reads the alignment.
-  cerr << "Reading alignment..." << endl;
   start_time = Clock::now();
+  cerr << "Reading alignment..." << endl;
   shared_ptr<Alignment> alignment =
       make_shared<Alignment>(vm["alignment"].as<string>());
   stop_time = Clock::now();
@@ -137,8 +137,8 @@ int main(int argc, char** argv) {
 
   // Constructs an index storing the occurrences in the source data for each
   // frequent collocation.
-  cerr << "Precomputing collocations..." << endl;
   start_time = Clock::now();
+  cerr << "Precomputing collocations..." << endl;
   shared_ptr<Precomputation> precomputation = make_shared<Precomputation>(
       source_suffix_array,
       vm["frequent"].as<int>(),
@@ -154,8 +154,8 @@ int main(int argc, char** argv) {
 
   // Constructs a table storing p(e | f) and p(f | e) for every pair of source
   // and target words.
-  cerr << "Precomputing conditional probabilities..." << endl;
   start_time = Clock::now();
+  cerr << "Precomputing conditional probabilities..." << endl;
   shared_ptr<TranslationTable> table = make_shared<TranslationTable>(
       source_data_array, target_data_array, alignment);
   stop_time = Clock::now();
@@ -229,7 +229,7 @@ int main(int argc, char** argv) {
   }
 
   for (size_t i = 0; i < sentences.size(); ++i) {
-    cout << "<seg grammar=\"" << GetGrammarFilePath(grammar_path, i) << "\" id=\""
+    cout << "<seg grammar=" << GetGrammarFilePath(grammar_path, i) << " id=\""
          << i << "\"> " << sentences[i] << " </seg> " << suffixes[i] << endl;
   }
 
diff --git a/extractor/suffix_array.cc b/extractor/suffix_array.cc
index 65b2d581..0cf4d1f6 100644
--- a/extractor/suffix_array.cc
+++ b/extractor/suffix_array.cc
@@ -186,20 +186,6 @@ shared_ptr<DataArray> SuffixArray::GetData() const {
   return data_array;
 }
 
-void SuffixArray::WriteBinary(const fs::path& filepath) const {
-  FILE* file = fopen(filepath.string().c_str(), "w");
-  assert(file);
-  data_array->WriteBinary(file);
-
-  int size = suffix_array.size();
-  fwrite(&size, sizeof(int), 1, file);
-  fwrite(suffix_array.data(), sizeof(int), size, file);
-
-  size = word_start.size();
-  fwrite(&size, sizeof(int), 1, file);
-  fwrite(word_start.data(), sizeof(int), size, file);
-}
-
 PhraseLocation SuffixArray::Lookup(int low, int high, const string& word,
                                    int offset) const {
   if (!data_array->HasWord(word)) {
@@ -232,4 +218,10 @@ int SuffixArray::LookupRangeStart(int low, int high, int word_id,
   return result;
 }
 
+bool SuffixArray::operator==(const SuffixArray& other) const {
+  return *data_array == *other.data_array &&
+         suffix_array == other.suffix_array &&
+         word_start == other.word_start;
+}
+
 } // namespace extractor
diff --git a/extractor/suffix_array.h b/extractor/suffix_array.h
index bf731d79..8ee454ec 100644
--- a/extractor/suffix_array.h
+++ b/extractor/suffix_array.h
@@ -6,6 +6,9 @@
 #include <vector>
 
 #include <boost/filesystem.hpp>
+#include <boost/serialization/serialization.hpp>
+#include <boost/serialization/split_member.hpp>
+#include <boost/serialization/vector.hpp>
 
 namespace fs = boost::filesystem;
 using namespace std;
@@ -20,6 +23,9 @@ class SuffixArray {
   // Creates a suffix array from a data array.
   SuffixArray(shared_ptr<DataArray> data_array);
 
+  // Creates empty suffix array.
+  SuffixArray();
+
   virtual ~SuffixArray();
 
   // Returns the size of the suffix array.
@@ -40,10 +46,7 @@ class SuffixArray {
   virtual PhraseLocation Lookup(int low, int high, const string& word,
                                 int offset) const;
 
-  void WriteBinary(const fs::path& filepath) const;
-
- protected:
-  SuffixArray();
+  bool operator==(const SuffixArray& other) const;
 
  private:
   // Constructs the suffix array using the algorithm of Larsson and Sadakane
@@ -65,6 +68,23 @@ class SuffixArray {
   // offset value is greater or equal to word_id.
   int LookupRangeStart(int low, int high, int word_id, int offset) const;
 
+  friend class boost::serialization::access;
+
+  template<class Archive> void save(Archive& ar, unsigned int) const {
+    ar << *data_array;
+    ar << suffix_array;
+    ar << word_start;
+  }
+
+  template<class Archive> void load(Archive& ar, unsigned int) {
+    data_array = make_shared<DataArray>();
+    ar >> *data_array;
+    ar >> suffix_array;
+    ar >> word_start;
+  }
+
+  BOOST_SERIALIZATION_SPLIT_MEMBER();
+
   shared_ptr<DataArray> data_array;
   vector<int> suffix_array;
   vector<int> word_start;
diff --git a/extractor/suffix_array_test.cc b/extractor/suffix_array_test.cc
index 8431a16e..ba0dbcc3 100644
--- a/extractor/suffix_array_test.cc
+++ b/extractor/suffix_array_test.cc
@@ -1,13 +1,17 @@
 #include <gtest/gtest.h>
 
+#include <vector>
+
+#include <boost/archive/binary_iarchive.hpp>
+#include <boost/archive/binary_oarchive.hpp>
+
 #include "mocks/mock_data_array.h"
 #include "phrase_location.h"
 #include "suffix_array.h"
 
-#include <vector>
-
 using namespace std;
 using namespace ::testing;
+namespace ar = boost::archive;
 
 namespace extractor {
 namespace {
@@ -20,30 +24,30 @@ class SuffixArrayTest : public Test {
     EXPECT_CALL(*data_array, GetData()).WillRepeatedly(ReturnRef(data));
     EXPECT_CALL(*data_array, GetVocabularySize()).WillRepeatedly(Return(7));
     EXPECT_CALL(*data_array, GetSize()).WillRepeatedly(Return(13));
-    suffix_array = make_shared<SuffixArray>(data_array);
+    suffix_array = SuffixArray(data_array);
   }
 
   vector<int> data;
-  shared_ptr<SuffixArray> suffix_array;
+  SuffixArray suffix_array;
   shared_ptr<MockDataArray> data_array;
 };
 
 TEST_F(SuffixArrayTest, TestData) {
-  EXPECT_EQ(data_array, suffix_array->GetData());
-  EXPECT_EQ(14, suffix_array->GetSize());
+  EXPECT_EQ(data_array, suffix_array.GetData());
+  EXPECT_EQ(14, suffix_array.GetSize());
 }
 
 TEST_F(SuffixArrayTest, TestBuildSuffixArray) {
   vector<int> expected_suffix_array =
       {13, 11, 2, 12, 3, 6, 10, 1, 4, 7, 5, 9, 0, 8};
   for (size_t i = 0; i < expected_suffix_array.size(); ++i) {
-    EXPECT_EQ(expected_suffix_array[i], suffix_array->GetSuffix(i));
+    EXPECT_EQ(expected_suffix_array[i], suffix_array.GetSuffix(i));
   }
 }
 
 TEST_F(SuffixArrayTest, TestBuildLCP) {
   vector<int> expected_lcp = {-1, 0, 2, 0, 1, 0, 0, 3, 1, 1, 0, 0, 4, 1};
-  EXPECT_EQ(expected_lcp, suffix_array->BuildLCPArray());
+  EXPECT_EQ(expected_lcp, suffix_array.BuildLCPArray());
 }
 
 TEST_F(SuffixArrayTest, TestLookup) {
@@ -53,25 +57,37 @@ TEST_F(SuffixArrayTest, TestLookup) {
 
   EXPECT_CALL(*data_array, HasWord("word1")).WillRepeatedly(Return(true));
   EXPECT_CALL(*data_array, GetWordId("word1")).WillRepeatedly(Return(6));
-  EXPECT_EQ(PhraseLocation(11, 14), suffix_array->Lookup(0, 14, "word1", 0));
+  EXPECT_EQ(PhraseLocation(11, 14), suffix_array.Lookup(0, 14, "word1", 0));
 
   EXPECT_CALL(*data_array, HasWord("word2")).WillRepeatedly(Return(false));
-  EXPECT_EQ(PhraseLocation(0, 0), suffix_array->Lookup(0, 14, "word2", 0));
+  EXPECT_EQ(PhraseLocation(0, 0), suffix_array.Lookup(0, 14, "word2", 0));
 
   EXPECT_CALL(*data_array, HasWord("word3")).WillRepeatedly(Return(true));
   EXPECT_CALL(*data_array, GetWordId("word3")).WillRepeatedly(Return(4));
-  EXPECT_EQ(PhraseLocation(11, 13), suffix_array->Lookup(11, 14, "word3", 1));
+  EXPECT_EQ(PhraseLocation(11, 13), suffix_array.Lookup(11, 14, "word3", 1));
 
   EXPECT_CALL(*data_array, HasWord("word4")).WillRepeatedly(Return(true));
   EXPECT_CALL(*data_array, GetWordId("word4")).WillRepeatedly(Return(1));
-  EXPECT_EQ(PhraseLocation(11, 13), suffix_array->Lookup(11, 13, "word4", 2));
+  EXPECT_EQ(PhraseLocation(11, 13), suffix_array.Lookup(11, 13, "word4", 2));
 
   EXPECT_CALL(*data_array, HasWord("word5")).WillRepeatedly(Return(true));
   EXPECT_CALL(*data_array, GetWordId("word5")).WillRepeatedly(Return(2));
-  EXPECT_EQ(PhraseLocation(11, 13), suffix_array->Lookup(11, 13, "word5", 3));
+  EXPECT_EQ(PhraseLocation(11, 13), suffix_array.Lookup(11, 13, "word5", 3));
+
+  EXPECT_EQ(PhraseLocation(12, 13), suffix_array.Lookup(11, 13, "word3", 4));
+  EXPECT_EQ(PhraseLocation(11, 11), suffix_array.Lookup(11, 13, "word5", 1));
+}
+
+TEST_F(SuffixArrayTest, TestSerialization) {
+  stringstream stream(ios_base::binary | ios_base::out | ios_base::in);
+  ar::binary_oarchive output_stream(stream, ar::no_header);
+  output_stream << suffix_array;
+
+  SuffixArray suffix_array_copy;
+  ar::binary_iarchive input_stream(stream, ar::no_header);
+  input_stream >> suffix_array_copy;
 
-  EXPECT_EQ(PhraseLocation(12, 13), suffix_array->Lookup(11, 13, "word3", 4));
-  EXPECT_EQ(PhraseLocation(11, 11), suffix_array->Lookup(11, 13, "word5", 1));
+  EXPECT_EQ(suffix_array, suffix_array_copy);
 }
 
 } // namespace
diff --git a/extractor/translation_table.cc b/extractor/translation_table.cc
index adb59cb5..1b1ba112 100644
--- a/extractor/translation_table.cc
+++ b/extractor/translation_table.cc
@@ -97,7 +97,12 @@ double TranslationTable::GetTargetGivenSourceScore(
 
   int source_id = source_data_array->GetWordId(source_word);
   int target_id = target_data_array->GetWordId(target_word);
-  return translation_probabilities[make_pair(source_id, target_id)].first;
+  auto entry = make_pair(source_id, target_id);
+  auto it = translation_probabilities.find(entry);
+  if (it == translation_probabilities.end()) {
+    return 0;
+  }
+  return it->second.first;
 }
 
 double TranslationTable::GetSourceGivenTargetScore(
@@ -109,18 +114,18 @@ double TranslationTable::GetSourceGivenTargetScore(
 
   int source_id = source_data_array->GetWordId(source_word);
   int target_id = target_data_array->GetWordId(target_word);
-  return translation_probabilities[make_pair(source_id, target_id)].second;
+  auto entry = make_pair(source_id, target_id);
+  auto it = translation_probabilities.find(entry);
+  if (it == translation_probabilities.end()) {
+    return 0;
+  }
+  return it->second.second;
 }
 
-void TranslationTable::WriteBinary(const fs::path& filepath) const {
-  FILE* file = fopen(filepath.string().c_str(), "w");
-
-  int size = translation_probabilities.size();
-  fwrite(&size, sizeof(int), 1, file);
-  for (auto entry: translation_probabilities) {
-    fwrite(&entry.first, sizeof(entry.first), 1, file);
-    fwrite(&entry.second, sizeof(entry.second), 1, file);
-  }
+bool TranslationTable::operator==(const TranslationTable& other) const {
+  return *source_data_array == *other.source_data_array &&
+         *target_data_array == *other.target_data_array &&
+         translation_probabilities == other.translation_probabilities;
 }
 
 } // namespace extractor
diff --git a/extractor/translation_table.h b/extractor/translation_table.h
index ed43ad72..2a37bab7 100644
--- a/extractor/translation_table.h
+++ b/extractor/translation_table.h
@@ -7,6 +7,9 @@
 
 #include <boost/filesystem.hpp>
 #include <boost/functional/hash.hpp>
+#include <boost/serialization/serialization.hpp>
+#include <boost/serialization/split_member.hpp>
+#include <boost/serialization/utility.hpp>
 
 using namespace std;
 namespace fs = boost::filesystem;
@@ -23,11 +26,16 @@ class DataArray;
  */
 class TranslationTable {
  public:
+  // Constructs a translation table from source data, target data and the
+  // corresponding alignment.
   TranslationTable(
       shared_ptr<DataArray> source_data_array,
       shared_ptr<DataArray> target_data_array,
       shared_ptr<Alignment> alignment);
 
+  // Creates empty translation table.
+  TranslationTable();
+
   virtual ~TranslationTable();
 
   // Returns p(e | f).
@@ -38,10 +46,7 @@ class TranslationTable {
   virtual double GetSourceGivenTargetScore(const string& source_word,
                                            const string& target_word);
 
-  void WriteBinary(const fs::path& filepath) const;
-
- protected:
-  TranslationTable();
+  bool operator==(const TranslationTable& other) const;
 
  private:
   // Increment links count for the given (f, e) word pair.
@@ -52,6 +57,35 @@ class TranslationTable {
       int source_word_id,
       int target_word_id) const;
 
+  friend class boost::serialization::access;
+
+  template<class Archive> void save(Archive& ar, unsigned int) const {
+    ar << *source_data_array << *target_data_array;
+
+    int num_entries = translation_probabilities.size();
+    ar << num_entries;
+    for (auto entry: translation_probabilities) {
+      ar << entry;
+    }
+  }
+
+  template<class Archive> void load(Archive& ar, unsigned int) {
+    source_data_array = make_shared<DataArray>();
+    ar >> *source_data_array;
+    target_data_array = make_shared<DataArray>();
+    ar >> *target_data_array;
+
+    int num_entries;
+    ar >> num_entries;
+    for (size_t i = 0; i < num_entries; ++i) {
+      pair<pair<int, int>, pair<double, double>> entry;
+      ar >> entry;
+      translation_probabilities.insert(entry);
+    }
+  }
+
+  BOOST_SERIALIZATION_SPLIT_MEMBER();
+
   shared_ptr<DataArray> source_data_array;
   shared_ptr<DataArray> target_data_array;
   unordered_map<pair<int, int>, pair<double, double>, PairHash>
diff --git a/extractor/translation_table_test.cc b/extractor/translation_table_test.cc
index d14f2f89..606777bd 100644
--- a/extractor/translation_table_test.cc
+++ b/extractor/translation_table_test.cc
@@ -1,83 +1,106 @@
 #include <gtest/gtest.h>
 
 #include <memory>
+#include <sstream>
 #include <string>
 #include <vector>
 
+#include <boost/archive/binary_iarchive.hpp>
+#include <boost/archive/binary_oarchive.hpp>
+
 #include "mocks/mock_alignment.h"
 #include "mocks/mock_data_array.h"
 #include "translation_table.h"
 
 using namespace std;
 using namespace ::testing;
+namespace ar = boost::archive;
 
 namespace extractor {
 namespace {
 
-TEST(TranslationTableTest, TestScores) {
-  vector<string> words = {"a", "b", "c"};
-
-  vector<int> source_data = {2, 3, 2, 3, 4, 0, 2, 3, 6, 0, 2, 3, 6, 0};
-  vector<int> source_sentence_start = {0, 6, 10, 14};
-  shared_ptr<MockDataArray> source_data_array = make_shared<MockDataArray>();
-  EXPECT_CALL(*source_data_array, GetData())
-      .WillRepeatedly(ReturnRef(source_data));
-  EXPECT_CALL(*source_data_array, GetNumSentences())
-      .WillRepeatedly(Return(3));
-  for (size_t i = 0; i < source_sentence_start.size(); ++i) {
-    EXPECT_CALL(*source_data_array, GetSentenceStart(i))
-        .WillRepeatedly(Return(source_sentence_start[i]));
-  }
-  for (size_t i = 0; i < words.size(); ++i) {
-    EXPECT_CALL(*source_data_array, HasWord(words[i]))
-        .WillRepeatedly(Return(true));
-    EXPECT_CALL(*source_data_array, GetWordId(words[i]))
-        .WillRepeatedly(Return(i + 2));
-  }
-  EXPECT_CALL(*source_data_array, HasWord("d"))
-      .WillRepeatedly(Return(false));
-
-  vector<int> target_data = {2, 3, 2, 3, 4, 5, 0, 3, 6, 0, 2, 7, 0};
-  vector<int> target_sentence_start = {0, 7, 10, 13};
-  shared_ptr<MockDataArray> target_data_array = make_shared<MockDataArray>();
-  EXPECT_CALL(*target_data_array, GetData())
-      .WillRepeatedly(ReturnRef(target_data));
-  for (size_t i = 0; i < target_sentence_start.size(); ++i) {
-    EXPECT_CALL(*target_data_array, GetSentenceStart(i))
-        .WillRepeatedly(Return(target_sentence_start[i]));
-  }
-  for (size_t i = 0; i < words.size(); ++i) {
-    EXPECT_CALL(*target_data_array, HasWord(words[i]))
-        .WillRepeatedly(Return(true));
-    EXPECT_CALL(*target_data_array, GetWordId(words[i]))
-        .WillRepeatedly(Return(i + 2));
+class TranslationTableTest : public Test {
+ protected:
+  virtual void SetUp() {
+    vector<string> words = {"a", "b", "c"};
+
+    vector<int> source_data = {2, 3, 2, 3, 4, 0, 2, 3, 6, 0, 2, 3, 6, 0};
+    vector<int> source_sentence_start = {0, 6, 10, 14};
+    shared_ptr<MockDataArray> source_data_array = make_shared<MockDataArray>();
+    EXPECT_CALL(*source_data_array, GetData())
+        .WillRepeatedly(ReturnRef(source_data));
+    EXPECT_CALL(*source_data_array, GetNumSentences())
+        .WillRepeatedly(Return(3));
+    for (size_t i = 0; i < source_sentence_start.size(); ++i) {
+      EXPECT_CALL(*source_data_array, GetSentenceStart(i))
+          .WillRepeatedly(Return(source_sentence_start[i]));
+    }
+    for (size_t i = 0; i < words.size(); ++i) {
+      EXPECT_CALL(*source_data_array, HasWord(words[i]))
+          .WillRepeatedly(Return(true));
+      EXPECT_CALL(*source_data_array, GetWordId(words[i]))
+          .WillRepeatedly(Return(i + 2));
+    }
+    EXPECT_CALL(*source_data_array, HasWord("d"))
+        .WillRepeatedly(Return(false));
+
+    vector<int> target_data = {2, 3, 2, 3, 4, 5, 0, 3, 6, 0, 2, 7, 0};
+    vector<int> target_sentence_start = {0, 7, 10, 13};
+    shared_ptr<MockDataArray> target_data_array = make_shared<MockDataArray>();
+    EXPECT_CALL(*target_data_array, GetData())
+        .WillRepeatedly(ReturnRef(target_data));
+    for (size_t i = 0; i < target_sentence_start.size(); ++i) {
+      EXPECT_CALL(*target_data_array, GetSentenceStart(i))
+          .WillRepeatedly(Return(target_sentence_start[i]));
+    }
+    for (size_t i = 0; i < words.size(); ++i) {
+      EXPECT_CALL(*target_data_array, HasWord(words[i]))
+          .WillRepeatedly(Return(true));
+      EXPECT_CALL(*target_data_array, GetWordId(words[i]))
+          .WillRepeatedly(Return(i + 2));
+    }
+    EXPECT_CALL(*target_data_array, HasWord("d"))
+        .WillRepeatedly(Return(false));
+
+    vector<pair<int, int>> links1 = {
+      make_pair(0, 0), make_pair(1, 1), make_pair(2, 2), make_pair(3, 3),
+      make_pair(4, 4), make_pair(4, 5)
+    };
+    vector<pair<int, int>> links2 = {make_pair(1, 0), make_pair(2, 1)};
+    vector<pair<int, int>> links3 = {make_pair(0, 0), make_pair(2, 1)};
+    shared_ptr<MockAlignment> alignment = make_shared<MockAlignment>();
+    EXPECT_CALL(*alignment, GetLinks(0)).WillRepeatedly(Return(links1));
+    EXPECT_CALL(*alignment, GetLinks(1)).WillRepeatedly(Return(links2));
+    EXPECT_CALL(*alignment, GetLinks(2)).WillRepeatedly(Return(links3));
+
+    table = TranslationTable(source_data_array, target_data_array, alignment);
   }
-  EXPECT_CALL(*target_data_array, HasWord("d"))
-      .WillRepeatedly(Return(false));
-
-  vector<pair<int, int>> links1 = {
-    make_pair(0, 0), make_pair(1, 1), make_pair(2, 2), make_pair(3, 3),
-    make_pair(4, 4), make_pair(4, 5)
-  };
-  vector<pair<int, int>> links2 = {make_pair(1, 0), make_pair(2, 1)};
-  vector<pair<int, int>> links3 = {make_pair(0, 0), make_pair(2, 1)};
-  shared_ptr<MockAlignment> alignment = make_shared<MockAlignment>();
-  EXPECT_CALL(*alignment, GetLinks(0)).WillRepeatedly(Return(links1));
-  EXPECT_CALL(*alignment, GetLinks(1)).WillRepeatedly(Return(links2));
-  EXPECT_CALL(*alignment, GetLinks(2)).WillRepeatedly(Return(links3));
-
-  shared_ptr<TranslationTable> table = make_shared<TranslationTable>(
-      source_data_array, target_data_array, alignment);
-
-  EXPECT_EQ(0.75, table->GetTargetGivenSourceScore("a", "a"));
-  EXPECT_EQ(0, table->GetTargetGivenSourceScore("a", "b"));
-  EXPECT_EQ(0.5, table->GetTargetGivenSourceScore("c", "c"));
-  EXPECT_EQ(-1, table->GetTargetGivenSourceScore("c", "d"));
-
-  EXPECT_EQ(1, table->GetSourceGivenTargetScore("a", "a"));
-  EXPECT_EQ(0, table->GetSourceGivenTargetScore("a", "b"));
-  EXPECT_EQ(1, table->GetSourceGivenTargetScore("c", "c"));
-  EXPECT_EQ(-1, table->GetSourceGivenTargetScore("c", "d"));
+
+  TranslationTable table;
+};
+
+TEST_F(TranslationTableTest, TestScores) {
+  EXPECT_EQ(0.75, table.GetTargetGivenSourceScore("a", "a"));
+  EXPECT_EQ(0, table.GetTargetGivenSourceScore("a", "b"));
+  EXPECT_EQ(0.5, table.GetTargetGivenSourceScore("c", "c"));
+  EXPECT_EQ(-1, table.GetTargetGivenSourceScore("c", "d"));
+
+  EXPECT_EQ(1, table.GetSourceGivenTargetScore("a", "a"));
+  EXPECT_EQ(0, table.GetSourceGivenTargetScore("a", "b"));
+  EXPECT_EQ(1, table.GetSourceGivenTargetScore("c", "c"));
+  EXPECT_EQ(-1, table.GetSourceGivenTargetScore("c", "d"));
+}
+
+TEST_F(TranslationTableTest, TestSerialization) {
+  stringstream stream(ios_base::binary | ios_base::out | ios_base::in);
+  ar::binary_oarchive output_stream(stream, ar::no_header);
+  output_stream << table;
+
+  TranslationTable table_copy;
+  ar::binary_iarchive input_stream(stream, ar::no_header);
+  input_stream >> table_copy;
+
+  EXPECT_EQ(table, table_copy);
 }
 
 } // namespace