1 files changed, 17 insertions, 0 deletions
diff --git a/extractor/features/is_source_singleton.cc b/extractor/features/is_source_singleton.cc
new file mode 100644
index 00000000..1abb486f
--- /dev/null
+++ b/extractor/features/is_source_singleton.cc
@@ -0,0 +1,17 @@
+#include "is_source_singleton.h"
+
+#include <cmath>
+
+namespace extractor {
+namespace features {
+
+double IsSourceSingleton::Score(const FeatureContext& context) const {
+  return fabs(context.source_phrase_count - 1) < 1e-6;
+}
+
+string IsSourceSingleton::GetName() const {
+  return "IsSingletonF";
+}
+
+} // namespace features
+} // namespace extractor