Batched load of textual inversions (#3277)

* Batched load of textual inversions

- Only call resize_token_embeddings once per batch as it is the most expensive operation
- Allow pretrained_model_name_or_path and token to be an optional list
- Remove Dict from type annotation pretrained_model_name_or_path as it was not supported in this function
- Add comment that single files (e.g. .pt/.safetensors) are supported
- Add comment for token parameter
- Convert token override log message from warning to info

* Update src/diffusers/loaders.py

Check for duplicate tokens
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

* Update condition for None tokens

---------
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

src/diffusers/loaders.py

@@ -436,7 +436,10 @@ class TextualInversionLoaderMixin:
         return prompt
 
     def load_textual_inversion(
-        self, pretrained_model_name_or_path: Union[str, Dict[str, torch.Tensor]], token: Optional[str] = None, **kwargs
+        self,
+        pretrained_model_name_or_path: Union[str, List[str]],
+        token: Optional[Union[str, List[str]]] = None,
+        **kwargs,
     ):
         r"""
         Load textual inversion embeddings into the text encoder of stable diffusion pipelines. Both `diffusers` and
@@ -449,7 +452,7 @@ class TextualInversionLoaderMixin:
         </Tip>
 
         Parameters:
-            pretrained_model_name_or_path (`str` or `os.PathLike`):
+            pretrained_model_name_or_path (`str` or `os.PathLike` or `List[str or os.PathLike]`):
                 Can be either:
 
                     - A string, the *model id* of a pretrained model hosted inside a model repo on huggingface.co.
@@ -457,6 +460,12 @@ class TextualInversionLoaderMixin:
                       `"sd-concepts-library/low-poly-hd-logos-icons"`.
                     - A path to a *directory* containing textual inversion weights, e.g.
                       `./my_text_inversion_directory/`.
+                    - A path to a *file* containing textual inversion weights, e.g. `./my_text_inversions.pt`.
+
+                Or a list of those elements.
+            token (`str` or `List[str]`, *optional*):
+                Override the token to use for the textual inversion weights. If `pretrained_model_name_or_path` is a
+                list, then `token` must also be a list of equal length.
             weight_name (`str`, *optional*):
                 Name of a custom weight file. This should be used in two cases:
 
@@ -576,16 +585,62 @@ class TextualInversionLoaderMixin:
             "framework": "pytorch",
         }
 
-        # 1. Load textual inversion file
-        model_file = None
-        # Let's first try to load .safetensors weights
-        if (use_safetensors and weight_name is None) or (
-            weight_name is not None and weight_name.endswith(".safetensors")
-        ):
-            try:
+        if isinstance(pretrained_model_name_or_path, str):
+            pretrained_model_name_or_paths = [pretrained_model_name_or_path]
+        else:
+            pretrained_model_name_or_paths = pretrained_model_name_or_path
+
+        if isinstance(token, str):
+            tokens = [token]
+        elif token is None:
+            tokens = [None] * len(pretrained_model_name_or_paths)
+        else:
+            tokens = token
+
+        if len(pretrained_model_name_or_paths) != len(tokens):
+            raise ValueError(
+                f"You have passed a list of models of length {len(pretrained_model_name_or_paths)}, and list of tokens of length {len(tokens)}"
+                f"Make sure both lists have the same length."
+            )
+
+        valid_tokens = [t for t in tokens if t is not None]
+        if len(set(valid_tokens)) < len(valid_tokens):
+            raise ValueError(f"You have passed a list of tokens that contains duplicates: {tokens}")
+
+        token_ids_and_embeddings = []
+
+        for pretrained_model_name_or_path, token in zip(pretrained_model_name_or_paths, tokens):
+            # 1. Load textual inversion file
+            model_file = None
+            # Let's first try to load .safetensors weights
+            if (use_safetensors and weight_name is None) or (
+                weight_name is not None and weight_name.endswith(".safetensors")
+            ):
+                try:
+                    model_file = _get_model_file(
+                        pretrained_model_name_or_path,
+                        weights_name=weight_name or TEXT_INVERSION_NAME_SAFE,
+                        cache_dir=cache_dir,
+                        force_download=force_download,
+                        resume_download=resume_download,
+                        proxies=proxies,
+                        local_files_only=local_files_only,
+                        use_auth_token=use_auth_token,
+                        revision=revision,
+                        subfolder=subfolder,
+                        user_agent=user_agent,
+                    )
+                    state_dict = safetensors.torch.load_file(model_file, device="cpu")
+                except Exception as e:
+                    if not allow_pickle:
+                        raise e
+
+                    model_file = None
+
+            if model_file is None:
                 model_file = _get_model_file(
                     pretrained_model_name_or_path,
-                    weights_name=weight_name or TEXT_INVERSION_NAME_SAFE,
+                    weights_name=weight_name or TEXT_INVERSION_NAME,
                     cache_dir=cache_dir,
                     force_download=force_download,
                     resume_download=resume_download,
@@ -596,88 +651,68 @@ class TextualInversionLoaderMixin:
                     subfolder=subfolder,
                     user_agent=user_agent,
                 )
-                state_dict = safetensors.torch.load_file(model_file, device="cpu")
-            except Exception as e:
-                if not allow_pickle:
-                    raise e
+                state_dict = torch.load(model_file, map_location="cpu")
 
-                model_file = None
+            # 2. Load token and embedding correcly from file
+            if isinstance(state_dict, torch.Tensor):
+                if token is None:
+                    raise ValueError(
+                        "You are trying to load a textual inversion embedding that has been saved as a PyTorch tensor. Make sure to pass the name of the corresponding token in this case: `token=...`."
+                    )
+                embedding = state_dict
+            elif len(state_dict) == 1:
+                # diffusers
+                loaded_token, embedding = next(iter(state_dict.items()))
+            elif "string_to_param" in state_dict:
+                # A1111
+                loaded_token = state_dict["name"]
+                embedding = state_dict["string_to_param"]["*"]
+
+            if token is not None and loaded_token != token:
+                logger.info(f"The loaded token: {loaded_token} is overwritten by the passed token {token}.")
+            else:
+                token = loaded_token
 
-        if model_file is None:
-            model_file = _get_model_file(
-                pretrained_model_name_or_path,
-                weights_name=weight_name or TEXT_INVERSION_NAME,
-                cache_dir=cache_dir,
-                force_download=force_download,
-                resume_download=resume_download,
-                proxies=proxies,
-                local_files_only=local_files_only,
-                use_auth_token=use_auth_token,
-                revision=revision,
-                subfolder=subfolder,
-                user_agent=user_agent,
-            )
-            state_dict = torch.load(model_file, map_location="cpu")
+            embedding = embedding.to(dtype=self.text_encoder.dtype, device=self.text_encoder.device)
 
-        # 2. Load token and embedding correcly from file
-        if isinstance(state_dict, torch.Tensor):
-            if token is None:
+            # 3. Make sure we don't mess up the tokenizer or text encoder
+            vocab = self.tokenizer.get_vocab()
+            if token in vocab:
                 raise ValueError(
-                    "You are trying to load a textual inversion embedding that has been saved as a PyTorch tensor. Make sure to pass the name of the corresponding token in this case: `token=...`."
+                    f"Token {token} already in tokenizer vocabulary. Please choose a different token name or remove {token} and embedding from the tokenizer and text encoder."
                 )
-            embedding = state_dict
-        elif len(state_dict) == 1:
-            # diffusers
-            loaded_token, embedding = next(iter(state_dict.items()))
-        elif "string_to_param" in state_dict:
-            # A1111
-            loaded_token = state_dict["name"]
-            embedding = state_dict["string_to_param"]["*"]
-
-        if token is not None and loaded_token != token:
-            logger.warn(f"The loaded token: {loaded_token} is overwritten by the passed token {token}.")
-        else:
-            token = loaded_token
-
-        embedding = embedding.to(dtype=self.text_encoder.dtype, device=self.text_encoder.device)
+            elif f"{token}_1" in vocab:
+                multi_vector_tokens = [token]
+                i = 1
+                while f"{token}_{i}" in self.tokenizer.added_tokens_encoder:
+                    multi_vector_tokens.append(f"{token}_{i}")
+                    i += 1
 
-        # 3. Make sure we don't mess up the tokenizer or text encoder
-        vocab = self.tokenizer.get_vocab()
-        if token in vocab:
-            raise ValueError(
-                f"Token {token} already in tokenizer vocabulary. Please choose a different token name or remove {token} and embedding from the tokenizer and text encoder."
-            )
-        elif f"{token}_1" in vocab:
-            multi_vector_tokens = [token]
-            i = 1
-            while f"{token}_{i}" in self.tokenizer.added_tokens_encoder:
-                multi_vector_tokens.append(f"{token}_{i}")
-                i += 1
+                raise ValueError(
+                    f"Multi-vector Token {multi_vector_tokens} already in tokenizer vocabulary. Please choose a different token name or remove the {multi_vector_tokens} and embedding from the tokenizer and text encoder."
+                )
 
-            raise ValueError(
-                f"Multi-vector Token {multi_vector_tokens} already in tokenizer vocabulary. Please choose a different token name or remove the {multi_vector_tokens} and embedding from the tokenizer and text encoder."
-            )
+            is_multi_vector = len(embedding.shape) > 1 and embedding.shape[0] > 1
 
-        is_multi_vector = len(embedding.shape) > 1 and embedding.shape[0] > 1
+            if is_multi_vector:
+                tokens = [token] + [f"{token}_{i}" for i in range(1, embedding.shape[0])]
+                embeddings = [e for e in embedding]  # noqa: C416
+            else:
+                tokens = [token]
+                embeddings = [embedding[0]] if len(embedding.shape) > 1 else [embedding]
 
-        if is_multi_vector:
-            tokens = [token] + [f"{token}_{i}" for i in range(1, embedding.shape[0])]
-            embeddings = [e for e in embedding]  # noqa: C416
-        else:
-            tokens = [token]
-            embeddings = [embedding[0]] if len(embedding.shape) > 1 else [embedding]
+            # add tokens and get ids
+            self.tokenizer.add_tokens(tokens)
+            token_ids = self.tokenizer.convert_tokens_to_ids(tokens)
+            token_ids_and_embeddings += zip(token_ids, embeddings)
 
-        # add tokens and get ids
-        self.tokenizer.add_tokens(tokens)
-        token_ids = self.tokenizer.convert_tokens_to_ids(tokens)
+            logger.info(f"Loaded textual inversion embedding for {token}.")
 
-        # resize token embeddings and set new embeddings
+        # resize token embeddings and set all new embeddings
         self.text_encoder.resize_token_embeddings(len(self.tokenizer))
-        for token_id, embedding in zip(token_ids, embeddings):
+        for token_id, embedding in token_ids_and_embeddings:
             self.text_encoder.get_input_embeddings().weight.data[token_id] = embedding
 
-        logger.info(f"Loaded textual inversion embedding for {token}.")
-
 
 class LoraLoaderMixin:
     r"""

tests/pipelines/test_pipelines.py

@@ -575,6 +575,31 @@ class DownloadTests(unittest.TestCase):
             out = pipe(prompt, num_inference_steps=1, output_type="numpy").images
             assert out.shape == (1, 128, 128, 3)
 
+        # multi embedding load
+        with tempfile.TemporaryDirectory() as tmpdirname1:
+            with tempfile.TemporaryDirectory() as tmpdirname2:
+                ten = {"<*****>": torch.ones((32,))}
+                torch.save(ten, os.path.join(tmpdirname1, "learned_embeds.bin"))
+
+                ten = {"<******>": 2 * torch.ones((1, 32))}
+                torch.save(ten, os.path.join(tmpdirname2, "learned_embeds.bin"))
+
+                pipe.load_textual_inversion([tmpdirname1, tmpdirname2])
+
+                token = pipe.tokenizer.convert_tokens_to_ids("<*****>")
+                assert token == num_tokens + 8, "Added token must be at spot `num_tokens`"
+                assert pipe.text_encoder.get_input_embeddings().weight[-2].sum().item() == 32
+                assert pipe._maybe_convert_prompt("<*****>", pipe.tokenizer) == "<*****>"
+
+                token = pipe.tokenizer.convert_tokens_to_ids("<******>")
+                assert token == num_tokens + 9, "Added token must be at spot `num_tokens`"
+                assert pipe.text_encoder.get_input_embeddings().weight[-1].sum().item() == 64
+                assert pipe._maybe_convert_prompt("<******>", pipe.tokenizer) == "<******>"
+
+                prompt = "hey <*****> <******>"
+                out = pipe(prompt, num_inference_steps=1, output_type="numpy").images
+                assert out.shape == (1, 128, 128, 3)
+
     def test_download_ignore_files(self):
         # Check https://huggingface.co/hf-internal-testing/tiny-stable-diffusion-pipe-ignore-files/blob/72f58636e5508a218c6b3f60550dc96445547817/model_index.json#L4
         with tempfile.TemporaryDirectory() as tmpdirname: