Ensure tensors are at least 1d for pad and concat (#17179)

* Ensure tensors are at least 1d for pad and concat

* Compatibility

* Fix

* Fix

* Add test

* Retrigger CI

* Consistency with master

* Retrigger CI

tests/trainer/test_trainer_utils.py

@@ -41,6 +41,8 @@ if is_torch_available():
         SequentialDistributedSampler,
         ShardSampler,
         get_parameter_names,
+        numpy_pad_and_concatenate,
+        torch_pad_and_concatenate,
     )
 
     class TstLayer(nn.Module):
@@ -459,6 +461,18 @@ class TrainerUtilsTest(unittest.TestCase):
             mock_training_loop_function()
             self.assertEqual("CUDA out of memory", cm.args[0])
 
+    def test_pad_and_concatenate_with_1d(self):
+        """Tests whether pad_and_concatenate works with scalars."""
+        array1 = 1.0
+        array2 = 2.0
+        result = numpy_pad_and_concatenate(array1, array2)
+        self.assertTrue(np.array_equal(np.array([1.0, 2.0]), result))
+
+        tensor1 = torch.tensor(1.0)
+        tensor2 = torch.tensor(2.0)
+        result = torch_pad_and_concatenate(tensor1, tensor2)
+        self.assertTrue(torch.equal(result, torch.Tensor([1.0, 2.0])))
+
     def test_remove_columns_collator(self):
         class MockLogger:
             def __init__(self) -> None: