From 92e0364f71fab6fdf40f1e8cd9b3b9deff99e88b Mon Sep 17 00:00:00 2001
From: Fred Blain <f.blain@sheffield.ac.uk>
Date: Thu, 25 Jun 2020 20:11:24 +0100
Subject: [PATCH] adding thresholds and QE scores.

---
 src/service/quality_estimation/qe.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/service/quality_estimation/qe.cpp b/src/service/quality_estimation/qe.cpp
index 7b430c7..e6d2d06 100644
--- a/src/service/quality_estimation/qe.cpp
+++ b/src/service/quality_estimation/qe.cpp
@@ -4,7 +4,16 @@ namespace qe {
 
 /// convert sentence score (log prob) to QE score
 int sentence_score2qe_score(const float sentence_score) {
-  return 42;
+  // empirically defined thresholds
+  float thresholds[2] = {-0.24869322, -0.10945034};
+
+  if (sentence_score < thresholds[0]) {
+    return 3;
+  } else if (sentence_score > thresholds[1]) {
+    return 1;
+  } else {
+    return 2;
+  }
 }
 
 }} // end of namespace marian::qea