Accepts BatchEncoding in LengthSampler (#11431)

src/transformers/trainer_pt_utils.py

@@ -33,6 +33,7 @@
 from torch.utils.data.sampler import RandomSampler, Sampler
 
 from .file_utils import is_sagemaker_dp_enabled, is_sagemaker_mp_enabled, is_torch_tpu_available
+from .tokenization_utils_base import BatchEncoding
 from .utils import logging
 
 
@@ -514,7 +515,10 @@ def __init__(
         self.batch_size = batch_size
         self.model_input_name = model_input_name if model_input_name is not None else "input_ids"
         if lengths is None:
-            if not isinstance(dataset[0], dict) or self.model_input_name not in dataset[0]:
+            if (
+                not (isinstance(dataset[0], dict) or isinstance(dataset[0], BatchEncoding))
+                or self.model_input_name not in dataset[0]
+            ):
                 raise ValueError(
                     "Can only automatically infer lengths for datasets whose items are dictionaries with an "
                     f"'{self.model_input_name}' key."
@@ -575,7 +579,10 @@ def __init__(
         self.model_input_name = model_input_name if model_input_name is not None else "input_ids"
 
         if lengths is None:
-            if not isinstance(dataset[0], dict) or self.model_input_name not in dataset[0]:
+            if (
+                not (isinstance(dataset[0], dict) or isinstance(dataset[0], BatchEncoding))
+                or self.model_input_name not in dataset[0]
+            ):
                 raise ValueError(
                     "Can only automatically infer lengths for datasets whose items are dictionaries with an "
                     f"'{self.model_input_name}' key."

tests/test_trainer_utils.py

@@ -27,6 +27,7 @@
     from torch.utils.data import IterableDataset
 
     from transformers.modeling_outputs import SequenceClassifierOutput
+    from transformers.tokenization_utils_base import BatchEncoding
     from transformers.trainer_pt_utils import (
         DistributedLengthGroupedSampler,
         DistributedSamplerWithLoop,
@@ -185,6 +186,36 @@ def test_group_by_length(self):
         # The indices should be a permutation of range(100)
         self.assertEqual(list(sorted(indices)), list(range(100)))
 
+    def test_group_by_length_with_dict(self):
+        # Get some inputs of random lengths
+        data = []
+        for _ in range(6):
+            input_ids = torch.randint(0, 25, (100,)).tolist()
+            data.append({"input_ids": input_ids})
+        # Put one bigger than the others to check it ends up in first position
+        data[3]["input_ids"] = torch.randint(0, 25, (105,)).tolist()
+
+        indices = list(LengthGroupedSampler(data, 4))
+        # The biggest element should be first
+        self.assertEqual(len(data[indices[0]]["input_ids"]), 105)
+        # The indices should be a permutation of range(6)
+        self.assertEqual(list(sorted(indices)), list(range(6)))
+
+    def test_group_by_length_with_batch_encoding(self):
+        # Get some inputs of random lengths
+        data = []
+        for _ in range(6):
+            input_ids = torch.randint(0, 25, (100,)).tolist()
+            data.append(BatchEncoding({"input_ids": input_ids}))
+        # Put one bigger than the others to check it ends up in first position
+        data[3]["input_ids"] = torch.randint(0, 25, (105,)).tolist()
+
+        indices = list(LengthGroupedSampler(data, 4))
+        # The biggest element should be first
+        self.assertEqual(len(data[indices[0]]["input_ids"]), 105)
+        # The indices should be a permutation of range(6)
+        self.assertEqual(list(sorted(indices)), list(range(6)))
+
     def test_distributed_length_grouped(self):
         # Get some inputs of random lengths
         lengths = torch.randint(0, 25, (100,)).tolist()