modity code structure

Former-commit-id: 0682ed357210897e0b67c4a6eb31a94b3eb929f1

src/llmtuner/tuner/rm/collator.py

@@ -0,0 +1,19 @@
+import torch
+from typing import Any, Dict, Sequence
+from transformers import DataCollatorWithPadding
+
+
+class PairwiseDataCollatorWithPadding(DataCollatorWithPadding):
+    r"""
+    Data collator for pairwise data.
+    """
+
+    def __call__(self, features: Sequence[Dict[str, Any]]) -> Dict[str, torch.Tensor]:
+        r"""
+        Pads batched data to the longest sequence in the batch.
+
+        We generate 2 * n examples where the first n examples represent chosen examples and
+        the last n examples represent rejected examples.
+        """
+        features = [{"input_ids": feature[key]} for key in ("accept_ids", "reject_ids") for feature in features]
+        return super().__call__(features)