support batch_eval_metrics, fix #4826

Former-commit-id: 3fe1df17188825f8a32fbe6a1294b4b532ce0c85

src/llamafactory/train/rm/metric.py

@@ -12,14 +12,30 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import TYPE_CHECKING, Dict
+from dataclasses import dataclass
+from typing import TYPE_CHECKING, Dict, Optional
 
 import numpy as np
 
+from ...extras.misc import numpify
+
 
 if TYPE_CHECKING:
     from transformers import EvalPrediction
 
 
-def compute_accuracy(eval_preds: "EvalPrediction") -> Dict[str, float]:
-    return {"accuracy": np.mean(eval_preds.predictions[0] > eval_preds.predictions[1])}
+@dataclass
+class ComputeAccuracy:
+    def __post_init__(self):
+        self.score_dict = {"accuracy": []}
+
+    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])
+        if not chosen_scores.shape:
+            self.score_dict["accuracy"].append(chosen_scores > rejected_scores)
+        else:
+            for i in range(len(chosen_scores)):
+                self.score_dict["accuracy"].append(chosen_scores[i] > rejected_scores[i])
+
+        if compute_result:
+            return {"accuracy": float(np.mean(self.score_dict["accuracy"]))}

src/llamafactory/train/rm/workflow.py

@@ -22,7 +22,7 @@ from ...extras.ploting import plot_loss
 from ...model import load_model, load_tokenizer
 from ..callbacks import fix_valuehead_checkpoint
 from ..trainer_utils import create_modelcard_and_push
-from .metric import compute_accuracy
+from .metric import ComputeAccuracy
 from .trainer import PairwiseTrainer
 
 
@@ -55,7 +55,7 @@ def run_rm(
         finetuning_args=finetuning_args,
         data_collator=data_collator,
         callbacks=callbacks,
-        compute_metrics=compute_accuracy,
+        compute_metrics=ComputeAccuracy(),
         **dataset_module,
         **tokenizer_module,
     )