Update

app.py

@@ -46,6 +46,21 @@ def exact_match(prediction, truth):
 def compute_f1(prediction, truth):
   pred_tokens = normalize_text(prediction).split()
   truth_tokens = normalize_text(truth).split()
+  
+  # if either the prediction or the truth is no-answer then f1 = 1 if they agree, 0 otherwise
+  if len(pred_tokens) == 0 or len(truth_tokens) == 0:
+    return int(pred_tokens == truth_tokens)
+  
+  common_tokens = set(pred_tokens) & set(truth_tokens)
+  
+  # if there are no common tokens then f1 = 0
+  if len(common_tokens) == 0:
+    return 0
+  
+  prec = len(common_tokens) / len(pred_tokens)
+  rec = len(common_tokens) / len(truth_tokens)
+  
+  return round(2 * (prec * rec) / (prec + rec), 2)