Fix: loading DBRX back from saved path (#35728)

* fix dtype as dict for some models + add test

* add comment in tests

src/transformers/modeling_utils.py

@@ -4020,10 +4020,31 @@ def from_pretrained(
                             )
                     elif hasattr(torch, torch_dtype):
                         torch_dtype = getattr(torch, torch_dtype)
-                    else:
-                        raise ValueError(
-                            f'`torch_dtype` can be one of: `torch.dtype`, `"auto"` or a string of a valid `torch.dtype`, but received {torch_dtype}'
-                        )
+                        for sub_config_key in config.sub_configs.keys():
+                            sub_config = getattr(config, sub_config_key)
+                            sub_config.torch_dtype = torch_dtype
+                elif isinstance(torch_dtype, torch.dtype):
+                    for sub_config_key in config.sub_configs.keys():
+                        sub_config = getattr(config, sub_config_key)
+                        sub_config.torch_dtype = torch_dtype
+                elif isinstance(torch_dtype, dict):
+                    for key, curr_dtype in torch_dtype.items():
+                        if hasattr(config, key):
+                            value = getattr(config, key)
+                            value.torch_dtype = curr_dtype
+                    # main torch dtype for modules that aren't part of any sub-config
+                    torch_dtype = torch_dtype.get("")
+                    config.torch_dtype = torch_dtype
+                    if isinstance(torch_dtype, str) and hasattr(torch, torch_dtype):
+                        torch_dtype = getattr(torch, torch_dtype)
+                    elif torch_dtype is None:
+                        torch_dtype = torch.float32
+                else:
+                    raise ValueError(
+                        f"`torch_dtype` can be one of: `torch.dtype`, `'auto'`, a string of a valid `torch.dtype` or a `dict` with valid `torch_dtype` "
+                        f"for each sub-config in composite configs, but received {torch_dtype}"
+                    )
+
                 dtype_orig = cls._set_default_torch_dtype(torch_dtype)
 
             # Check if `_keep_in_fp32_modules` is not None

src/transformers/models/dbrx/configuration_dbrx.py

@@ -57,7 +57,7 @@ def __init__(
         self.kv_n_heads = kv_n_heads
         self.rope_theta = rope_theta
 
-        for k in ["model_type", "attn_implementation", "transformers_version", "_commit_hash"]:
+        for k in ["model_type", "attn_implementation", "transformers_version", "_commit_hash", "torch_dtype"]:
             if k in kwargs:
                 kwargs.pop(k)
         if len(kwargs) != 0:
@@ -109,7 +109,7 @@ def __init__(
         self.moe_loss_weight = moe_loss_weight
         self.moe_normalize_expert_weights = moe_normalize_expert_weights
 
-        for k in ["model_type", "attn_implementation", "transformers_version", "_commit_hash"]:
+        for k in ["model_type", "attn_implementation", "transformers_version", "_commit_hash", "torch_dtype"]:
             if k in kwargs:
                 kwargs.pop(k)
         if len(kwargs) != 0:

tests/test_modeling_common.py

@@ -331,6 +331,12 @@ def check_save_load(out1, out2):
                 with torch.no_grad():
                     second = model(**self._prepare_for_class(inputs_dict, model_class))[0]
 
+                # Save and load second time because `from_pretrained` adds a bunch of new config fields
+                # so we need to make sure those fields can be loaded back after saving
+                # Simply init as `model(config)` doesn't add those fields
+                model.save_pretrained(tmpdirname)
+                model = model_class.from_pretrained(tmpdirname)
+
             if isinstance(first, tuple) and isinstance(second, tuple):
                 for tensor1, tensor2 in zip(first, second):
                     check_save_load(tensor1, tensor2)

tests/utils/test_modeling_utils.py

@@ -460,6 +460,60 @@ def test_model_from_config_torch_dtype_str(self):
         with self.assertRaises(ValueError):
             model = AutoModel.from_pretrained(TINY_T5, torch_dtype="int64")
 
+    def test_model_from_config_torch_dtype_composite(self):
+        """
+        Test that from_pretrained works with torch_dtype being as a dict per each sub-config in composite config
+        Tiny-Llava has saved auto dtype as `torch.float32` for all modules.
+        """
+        # should be able to set torch_dtype as a simple string and the model loads it correctly
+        model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA, torch_dtype="float32")
+        self.assertEqual(model.language_model.dtype, torch.float32)
+        self.assertEqual(model.vision_tower.dtype, torch.float32)
+
+        model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA, torch_dtype=torch.float16)
+        self.assertEqual(model.language_model.dtype, torch.float16)
+        self.assertEqual(model.vision_tower.dtype, torch.float16)
+
+        # should be able to set torch_dtype as a dict for each sub-config
+        model = LlavaForConditionalGeneration.from_pretrained(
+            TINY_LLAVA, torch_dtype={"text_config": "float32", "vision_config": "float16", "": "bfloat16"}
+        )
+        self.assertEqual(model.language_model.dtype, torch.float32)
+        self.assertEqual(model.vision_tower.dtype, torch.float16)
+        self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.bfloat16)
+
+        # should be able to set the values as torch.dtype (not str)
+        model = LlavaForConditionalGeneration.from_pretrained(
+            TINY_LLAVA, torch_dtype={"text_config": torch.float32, "vision_config": torch.float16, "": torch.bfloat16}
+        )
+        self.assertEqual(model.language_model.dtype, torch.float32)
+        self.assertEqual(model.vision_tower.dtype, torch.float16)
+        self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.bfloat16)
+
+        # should be able to set the values in configs directly and pass it to `from_pretrained`
+        config = copy.deepcopy(model.config)
+        config.text_config.torch_dtype = torch.float32
+        config.vision_config.torch_dtype = torch.bfloat16
+        config.torch_dtype = torch.float16
+        model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA, config=config, torch_dtype="auto")
+        self.assertEqual(model.language_model.dtype, torch.float32)
+        self.assertEqual(model.vision_tower.dtype, torch.bfloat16)
+        self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.float16)
+
+        # but if the model has `_keep_in_fp32_modules` then those modules should be in fp32 no matter what
+        LlavaForConditionalGeneration._keep_in_fp32_modules = ["multi_modal_projector"]
+        model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA, config=config, torch_dtype="auto")
+        self.assertEqual(model.language_model.dtype, torch.float32)
+        self.assertEqual(model.vision_tower.dtype, torch.bfloat16)
+        self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.float32)
+
+        # torch.set_default_dtype() supports only float dtypes, so will fail with non-float type
+        with self.assertRaises(ValueError):
+            model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA, torch_dtype="int64")
+            model = LlavaForConditionalGeneration.from_pretrained(
+                TINY_LLAVA, torch_dtype={"text_config": "float32", "vision_config": "int64", "": "float16"}
+            )
+
     @require_torch
     def test_model_from_pretrained_meta_device(self):
         def is_on_meta(model_id, dtype):