merge paul's extractor code

1 files changed, 37 insertions, 0 deletions

diff --git a/extractor/features/max_lex_target_given_source.cc b/extractor/features/max_lex_target_given_source.cc
new file mode 100644
index 00000000..33783054
--- /dev/null
+++ b/extractor/features/max_lex_target_given_source.cc
@@ -0,0 +1,37 @@
+#include "max_lex_target_given_source.h"
+
+#include <cmath>
+
+#include "data_array.h"
+#include "translation_table.h"
+
+namespace extractor {
+namespace features {
+
+MaxLexTargetGivenSource::MaxLexTargetGivenSource(
+    shared_ptr<TranslationTable> table) :
+    table(table) {}
+
+double MaxLexTargetGivenSource::Score(const FeatureContext& context) const {
+  vector<string> source_words = context.source_phrase.GetWords();
+  source_words.push_back(DataArray::NULL_WORD_STR);
+  vector<string> target_words = context.target_phrase.GetWords();
+
+  double score = 0;
+  for (string target_word: target_words) {
+    double max_score = 0;
+    for (string source_word: source_words) {
+      max_score = max(max_score,
+          table->GetTargetGivenSourceScore(source_word, target_word));
+    }
+    score += max_score > 0 ? -log10(max_score) : MAX_SCORE;
+  }
+  return score;
+}
+
+string MaxLexTargetGivenSource::GetName() const {
+  return "MaxLexEgivenF";
+}
+
+} // namespace features
+} // namespace extractor