fix div by 0 in smape-score by replacing all zeroes in denominator with 1

logmetric.py

@@ -130,12 +130,18 @@ class LogMetric(evaluate.Metric):
 
         if P_isnumber and R_isnumber:
             if P == 0 and R == 0: return 1.0      # since this leads to (|R| + |P|) = 0
-            n = 1
+            return 1 - (np.sum(np.abs(R - P) / (np.abs(R) + np.abs(P))))    # (n = 1)
         else:
             if P == [] and R == []: return 1.0     # since this leads to n = 0
             n = len(P)
-
-        return 1/n * np.sum(np.abs(R - P) / (np.abs(R) + np.abs(P)))
+            P = np.array(P)
+            R = np.array(R)
+            denominator = np.abs(R) + np.abs(P)
+            # Replace zeros in the denominator with 1 to avoid division by zero.
+            # the denominator[i] = 0 is only possible if R[i] == P[i] == 0, hence we can set denominator[i] = 1 and still achieve the result of 0 after division at index i
+            denominator[denominator == 0] = 1
+
+            return 1 - (1.0/n * np.sum(np.abs(R - P) / denominator))
 
     # splits both strings at \n and then computes the smape_score of their lengths
     def getLineCountScore(self, pred, ref):