fix metrics #4786

Former-commit-id: 7d0c4bd394fc3cba197db1719f1164b9dd66ac21

src/llamafactory/train/rm/metric.py

@@ -26,8 +26,16 @@ if TYPE_CHECKING:
 
 @dataclass
 class ComputeAccuracy:
-    def __post_init__(self):
+    def _dump(self) -> Optional[Dict[str, float]]:
+        result = None
+        if hasattr(self, "score_dict"):
+            result = {k: float(np.mean(v)) for k, v in self.score_dict.items()}
+
         self.score_dict = {"accuracy": []}
+        return result
+
+    def __post_init__(self):
+        self._dump()
 
     def __call__(self, eval_preds: "EvalPrediction", compute_result: bool = True) -> Optional[Dict[str, float]]:
         chosen_scores, rejected_scores = numpify(eval_preds.predictions[0]), numpify(eval_preds.predictions[1])
@@ -38,4 +46,4 @@ class ComputeAccuracy:
                 self.score_dict["accuracy"].append(chosen_scores[i] > rejected_scores[i])
 
         if compute_result:
-            return {"accuracy": float(np.mean(self.score_dict["accuracy"]))}
+            return self._dump()