Add example

app.py

@@ -1,7 +1,15 @@
 import gradio as gr
+from transformers import pipeline
 
-def greet(name):
-    return "Hello " + name + "!!"
+pipeline = pipeline(task="image-classification", model="julien-c/hotdog-not-hotdog")
 
-iface = gr.Interface(fn=greet, inputs="text", outputs="text")
-iface.launch()
+def predict(image):
+  predictions = pipeline(image)
+  return {p["label"]: p["score"] for p in predictions}
+
+gr.Interface(
+    predict,
+    inputs=gr.inputs.Image(label="Upload hot dog candidate", type="filepath"),
+    outputs=gr.outputs.Label(num_top_classes=2),
+    title="Hot Dog? Or Not?",
+).launch()

diffusers/__init__.py

@@ -0,0 +1,60 @@
+from .utils import (
+    is_inflect_available,
+    is_onnx_available,
+    is_scipy_available,
+    is_transformers_available,
+    is_unidecode_available,
+)
+
+
+__version__ = "0.3.0"
+
+from .configuration_utils import ConfigMixin
+from .modeling_utils import ModelMixin
+from .models import AutoencoderKL, UNet2DConditionModel, UNet2DModel, VQModel
+from .onnx_utils import OnnxRuntimeModel
+from .optimization import (
+    get_constant_schedule,
+    get_constant_schedule_with_warmup,
+    get_cosine_schedule_with_warmup,
+    get_cosine_with_hard_restarts_schedule_with_warmup,
+    get_linear_schedule_with_warmup,
+    get_polynomial_decay_schedule_with_warmup,
+    get_scheduler,
+)
+from .pipeline_utils import DiffusionPipeline
+from .pipelines import DDIMPipeline, DDPMPipeline, KarrasVePipeline, LDMPipeline, PNDMPipeline, ScoreSdeVePipeline
+from .schedulers import (
+    DDIMScheduler,
+    DDPMScheduler,
+    KarrasVeScheduler,
+    PNDMScheduler,
+    SchedulerMixin,
+    ScoreSdeVeScheduler,
+)
+from .utils import logging
+
+
+if is_scipy_available():
+    from .schedulers import LMSDiscreteScheduler
+else:
+    from .utils.dummy_scipy_objects import *  # noqa F403
+
+from .training_utils import EMAModel
+
+
+if is_transformers_available():
+    from .pipelines import (
+        LDMTextToImagePipeline,
+        StableDiffusionImg2ImgPipeline,
+        StableDiffusionInpaintPipeline,
+        StableDiffusionPipeline,
+    )
+else:
+    from .utils.dummy_transformers_objects import *  # noqa F403
+
+
+if is_transformers_available() and is_onnx_available():
+    from .pipelines import StableDiffusionOnnxPipeline
+else:
+    from .utils.dummy_transformers_and_onnx_objects import *  # noqa F403

diffusers/commands/__init__.py

@@ -0,0 +1,27 @@
+# Copyright 2022 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from abc import ABC, abstractmethod
+from argparse import ArgumentParser
+
+
+class BaseDiffusersCLICommand(ABC):
+    @staticmethod
+    @abstractmethod
+    def register_subcommand(parser: ArgumentParser):
+        raise NotImplementedError()
+
+    @abstractmethod
+    def run(self):
+        raise NotImplementedError()

diffusers/commands/diffusers_cli.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+# Copyright 2022 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from argparse import ArgumentParser
+
+from .env import EnvironmentCommand
+
+
+def main():
+    parser = ArgumentParser("Diffusers CLI tool", usage="diffusers-cli <command> [<args>]")
+    commands_parser = parser.add_subparsers(help="diffusers-cli command helpers")
+
+    # Register commands
+    EnvironmentCommand.register_subcommand(commands_parser)
+
+    # Let's go
+    args = parser.parse_args()
+
+    if not hasattr(args, "func"):
+        parser.print_help()
+        exit(1)
+
+    # Run
+    service = args.func(args)
+    service.run()
+
+
+if __name__ == "__main__":
+    main()

diffusers/commands/env.py

@@ -0,0 +1,70 @@
+# Copyright 2022 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import platform
+from argparse import ArgumentParser
+
+import huggingface_hub
+
+from .. import __version__ as version
+from ..utils import is_torch_available, is_transformers_available
+from . import BaseDiffusersCLICommand
+
+
+def info_command_factory(_):
+    return EnvironmentCommand()
+
+
+class EnvironmentCommand(BaseDiffusersCLICommand):
+    @staticmethod
+    def register_subcommand(parser: ArgumentParser):
+        download_parser = parser.add_parser("env")
+        download_parser.set_defaults(func=info_command_factory)
+
+    def run(self):
+        hub_version = huggingface_hub.__version__
+
+        pt_version = "not installed"
+        pt_cuda_available = "NA"
+        if is_torch_available():
+            import torch
+
+            pt_version = torch.__version__
+            pt_cuda_available = torch.cuda.is_available()
+
+        transformers_version = "not installed"
+        if is_transformers_available:
+            import transformers
+
+            transformers_version = transformers.__version__
+
+        info = {
+            "`diffusers` version": version,
+            "Platform": platform.platform(),
+            "Python version": platform.python_version(),
+            "PyTorch version (GPU?)": f"{pt_version} ({pt_cuda_available})",
+            "Huggingface_hub version": hub_version,
+            "Transformers version": transformers_version,
+            "Using GPU in script?": "<fill in>",
+            "Using distributed or parallel set-up in script?": "<fill in>",
+        }
+
+        print("\nCopy-and-paste the text below in your GitHub issue and FILL OUT the two last points.\n")
+        print(self.format_dict(info))
+
+        return info
+
+    @staticmethod
+    def format_dict(d):
+        return "\n".join([f"- {prop}: {val}" for prop, val in d.items()]) + "\n"

diffusers/configuration_utils.py

@@ -0,0 +1,403 @@
+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+# Copyright (c) 2022, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" ConfigMixinuration base class and utilities."""
+import functools
+import inspect
+import json
+import os
+import re
+from collections import OrderedDict
+from typing import Any, Dict, Tuple, Union
+
+from huggingface_hub import hf_hub_download
+from huggingface_hub.utils import EntryNotFoundError, RepositoryNotFoundError, RevisionNotFoundError
+from requests import HTTPError
+
+from . import __version__
+from .utils import DIFFUSERS_CACHE, HUGGINGFACE_CO_RESOLVE_ENDPOINT, logging
+
+
+logger = logging.get_logger(__name__)
+
+_re_configuration_file = re.compile(r"config\.(.*)\.json")
+
+
+class ConfigMixin:
+    r"""
+    Base class for all configuration classes. Stores all configuration parameters under `self.config` Also handles all
+    methods for loading/downloading/saving classes inheriting from [`ConfigMixin`] with
+        - [`~ConfigMixin.from_config`]
+        - [`~ConfigMixin.save_config`]
+
+    Class attributes:
+        - **config_name** (`str`) -- A filename under which the config should stored when calling
+          [`~ConfigMixin.save_config`] (should be overriden by parent class).
+        - **ignore_for_config** (`List[str]`) -- A list of attributes that should not be saved in the config (should be
+          overriden by parent class).
+    """
+    config_name = None
+    ignore_for_config = []
+
+    def register_to_config(self, **kwargs):
+        if self.config_name is None:
+            raise NotImplementedError(f"Make sure that {self.__class__} has defined a class name `config_name`")
+        kwargs["_class_name"] = self.__class__.__name__
+        kwargs["_diffusers_version"] = __version__
+
+        for key, value in kwargs.items():
+            try:
+                setattr(self, key, value)
+            except AttributeError as err:
+                logger.error(f"Can't set {key} with value {value} for {self}")
+                raise err
+
+        if not hasattr(self, "_internal_dict"):
+            internal_dict = kwargs
+        else:
+            previous_dict = dict(self._internal_dict)
+            internal_dict = {**self._internal_dict, **kwargs}
+            logger.debug(f"Updating config from {previous_dict} to {internal_dict}")
+
+        self._internal_dict = FrozenDict(internal_dict)
+
+    def save_config(self, save_directory: Union[str, os.PathLike], push_to_hub: bool = False, **kwargs):
+        """
+        Save a configuration object to the directory `save_directory`, so that it can be re-loaded using the
+        [`~ConfigMixin.from_config`] class method.
+
+        Args:
+            save_directory (`str` or `os.PathLike`):
+                Directory where the configuration JSON file will be saved (will be created if it does not exist).
+        """
+        if os.path.isfile(save_directory):
+            raise AssertionError(f"Provided path ({save_directory}) should be a directory, not a file")
+
+        os.makedirs(save_directory, exist_ok=True)
+
+        # If we save using the predefined names, we can load using `from_config`
+        output_config_file = os.path.join(save_directory, self.config_name)
+
+        self.to_json_file(output_config_file)
+        logger.info(f"ConfigMixinuration saved in {output_config_file}")
+
+    @classmethod
+    def from_config(cls, pretrained_model_name_or_path: Union[str, os.PathLike], return_unused_kwargs=False, **kwargs):
+        r"""
+        Instantiate a Python class from a pre-defined JSON-file.
+
+        Parameters:
+            pretrained_model_name_or_path (`str` or `os.PathLike`, *optional*):
+                Can be either:
+
+                    - A string, the *model id* of a model repo on huggingface.co. Valid model ids should have an
+                      organization name, like `google/ddpm-celebahq-256`.
+                    - A path to a *directory* containing model weights saved using [`~ConfigMixin.save_config`], e.g.,
+                      `./my_model_directory/`.
+
+            cache_dir (`Union[str, os.PathLike]`, *optional*):
+                Path to a directory in which a downloaded pretrained model configuration should be cached if the
+                standard cache should not be used.
+            ignore_mismatched_sizes (`bool`, *optional*, defaults to `False`):
+                Whether or not to raise an error if some of the weights from the checkpoint do not have the same size
+                as the weights of the model (if for instance, you are instantiating a model with 10 labels from a
+                checkpoint with 3 labels).
+            force_download (`bool`, *optional*, defaults to `False`):
+                Whether or not to force the (re-)download of the model weights and configuration files, overriding the
+                cached versions if they exist.
+            resume_download (`bool`, *optional*, defaults to `False`):
+                Whether or not to delete incompletely received files. Will attempt to resume the download if such a
+                file exists.
+            proxies (`Dict[str, str]`, *optional*):
+                A dictionary of proxy servers to use by protocol or endpoint, e.g., `{'http': 'foo.bar:3128',
+                'http://hostname': 'foo.bar:4012'}`. The proxies are used on each request.
+            output_loading_info(`bool`, *optional*, defaults to `False`):
+                Whether ot not to also return a dictionary containing missing keys, unexpected keys and error messages.
+            local_files_only(`bool`, *optional*, defaults to `False`):
+                Whether or not to only look at local files (i.e., do not try to download the model).
+            use_auth_token (`str` or *bool*, *optional*):
+                The token to use as HTTP bearer authorization for remote files. If `True`, will use the token generated
+                when running `transformers-cli login` (stored in `~/.huggingface`).
+            revision (`str`, *optional*, defaults to `"main"`):
+                The specific model version to use. It can be a branch name, a tag name, or a commit id, since we use a
+                git-based system for storing models and other artifacts on huggingface.co, so `revision` can be any
+                identifier allowed by git.
+            mirror (`str`, *optional*):
+                Mirror source to accelerate downloads in China. If you are from China and have an accessibility
+                problem, you can set this option to resolve it. Note that we do not guarantee the timeliness or safety.
+                Please refer to the mirror site for more information.
+
+        <Tip>
+
+        Passing `use_auth_token=True`` is required when you want to use a private model.
+
+        </Tip>
+
+        <Tip>
+
+        Activate the special ["offline-mode"](https://huggingface.co/transformers/installation.html#offline-mode) to
+        use this method in a firewalled environment.
+
+        </Tip>
+
+        """
+        config_dict = cls.get_config_dict(pretrained_model_name_or_path=pretrained_model_name_or_path, **kwargs)
+
+        init_dict, unused_kwargs = cls.extract_init_dict(config_dict, **kwargs)
+
+        model = cls(**init_dict)
+
+        if return_unused_kwargs:
+            return model, unused_kwargs
+        else:
+            return model
+
+    @classmethod
+    def get_config_dict(
+        cls, pretrained_model_name_or_path: Union[str, os.PathLike], **kwargs
+    ) -> Tuple[Dict[str, Any], Dict[str, Any]]:
+        cache_dir = kwargs.pop("cache_dir", DIFFUSERS_CACHE)
+        force_download = kwargs.pop("force_download", False)
+        resume_download = kwargs.pop("resume_download", False)
+        proxies = kwargs.pop("proxies", None)
+        use_auth_token = kwargs.pop("use_auth_token", None)
+        local_files_only = kwargs.pop("local_files_only", False)
+        revision = kwargs.pop("revision", None)
+        subfolder = kwargs.pop("subfolder", None)
+
+        user_agent = {"file_type": "config"}
+
+        pretrained_model_name_or_path = str(pretrained_model_name_or_path)
+
+        if cls.config_name is None:
+            raise ValueError(
+                "`self.config_name` is not defined. Note that one should not load a config from "
+                "`ConfigMixin`. Please make sure to define `config_name` in a class inheriting from `ConfigMixin`"
+            )
+
+        if os.path.isfile(pretrained_model_name_or_path):
+            config_file = pretrained_model_name_or_path
+        elif os.path.isdir(pretrained_model_name_or_path):
+            if os.path.isfile(os.path.join(pretrained_model_name_or_path, cls.config_name)):
+                # Load from a PyTorch checkpoint
+                config_file = os.path.join(pretrained_model_name_or_path, cls.config_name)
+            elif subfolder is not None and os.path.isfile(
+                os.path.join(pretrained_model_name_or_path, subfolder, cls.config_name)
+            ):
+                config_file = os.path.join(pretrained_model_name_or_path, subfolder, cls.config_name)
+            else:
+                raise EnvironmentError(
+                    f"Error no file named {cls.config_name} found in directory {pretrained_model_name_or_path}."
+                )
+        else:
+            try:
+                # Load from URL or cache if already cached
+                config_file = hf_hub_download(
+                    pretrained_model_name_or_path,
+                    filename=cls.config_name,
+                    cache_dir=cache_dir,
+                    force_download=force_download,
+                    proxies=proxies,
+                    resume_download=resume_download,
+                    local_files_only=local_files_only,
+                    use_auth_token=use_auth_token,
+                    user_agent=user_agent,
+                    subfolder=subfolder,
+                    revision=revision,
+                )
+
+            except RepositoryNotFoundError:
+                raise EnvironmentError(
+                    f"{pretrained_model_name_or_path} is not a local folder and is not a valid model identifier"
+                    " listed on 'https://huggingface.co/models'\nIf this is a private repository, make sure to pass a"
+                    " token having permission to this repo with `use_auth_token` or log in with `huggingface-cli"
+                    " login` and pass `use_auth_token=True`."
+                )
+            except RevisionNotFoundError:
+                raise EnvironmentError(
+                    f"{revision} is not a valid git identifier (branch name, tag name or commit id) that exists for"
+                    " this model name. Check the model page at"
+                    f" 'https://huggingface.co/{pretrained_model_name_or_path}' for available revisions."
+                )
+            except EntryNotFoundError:
+                raise EnvironmentError(
+                    f"{pretrained_model_name_or_path} does not appear to have a file named {cls.config_name}."
+                )
+            except HTTPError as err:
+                raise EnvironmentError(
+                    "There was a specific connection error when trying to load"
+                    f" {pretrained_model_name_or_path}:\n{err}"
+                )
+            except ValueError:
+                raise EnvironmentError(
+                    f"We couldn't connect to '{HUGGINGFACE_CO_RESOLVE_ENDPOINT}' to load this model, couldn't find it"
+                    f" in the cached files and it looks like {pretrained_model_name_or_path} is not the path to a"
+                    f" directory containing a {cls.config_name} file.\nCheckout your internet connection or see how to"
+                    " run the library in offline mode at"
+                    " 'https://huggingface.co/docs/diffusers/installation#offline-mode'."
+                )
+            except EnvironmentError:
+                raise EnvironmentError(
+                    f"Can't load config for '{pretrained_model_name_or_path}'. If you were trying to load it from "
+                    "'https://huggingface.co/models', make sure you don't have a local directory with the same name. "
+                    f"Otherwise, make sure '{pretrained_model_name_or_path}' is the correct path to a directory "
+                    f"containing a {cls.config_name} file"
+                )
+
+        try:
+            # Load config dict
+            config_dict = cls._dict_from_json_file(config_file)
+        except (json.JSONDecodeError, UnicodeDecodeError):
+            raise EnvironmentError(f"It looks like the config file at '{config_file}' is not a valid JSON file.")
+
+        return config_dict
+
+    @classmethod
+    def extract_init_dict(cls, config_dict, **kwargs):
+        expected_keys = set(dict(inspect.signature(cls.__init__).parameters).keys())
+        expected_keys.remove("self")
+        # remove general kwargs if present in dict
+        if "kwargs" in expected_keys:
+            expected_keys.remove("kwargs")
+        # remove keys to be ignored
+        if len(cls.ignore_for_config) > 0:
+            expected_keys = expected_keys - set(cls.ignore_for_config)
+        init_dict = {}
+        for key in expected_keys:
+            if key in kwargs:
+                # overwrite key
+                init_dict[key] = kwargs.pop(key)
+            elif key in config_dict:
+                # use value from config dict
+                init_dict[key] = config_dict.pop(key)
+
+        unused_kwargs = config_dict.update(kwargs)
+
+        passed_keys = set(init_dict.keys())
+        if len(expected_keys - passed_keys) > 0:
+            logger.warning(
+                f"{expected_keys - passed_keys} was not found in config. Values will be initialized to default values."
+            )
+
+        return init_dict, unused_kwargs
+
+    @classmethod
+    def _dict_from_json_file(cls, json_file: Union[str, os.PathLike]):
+        with open(json_file, "r", encoding="utf-8") as reader:
+            text = reader.read()
+        return json.loads(text)
+
+    def __repr__(self):
+        return f"{self.__class__.__name__} {self.to_json_string()}"
+
+    @property
+    def config(self) -> Dict[str, Any]:
+        return self._internal_dict
+
+    def to_json_string(self) -> str:
+        """
+        Serializes this instance to a JSON string.
+
+        Returns:
+            `str`: String containing all the attributes that make up this configuration instance in JSON format.
+        """
+        config_dict = self._internal_dict if hasattr(self, "_internal_dict") else {}
+        return json.dumps(config_dict, indent=2, sort_keys=True) + "\n"
+
+    def to_json_file(self, json_file_path: Union[str, os.PathLike]):
+        """
+        Save this instance to a JSON file.
+
+        Args:
+            json_file_path (`str` or `os.PathLike`):
+                Path to the JSON file in which this configuration instance's parameters will be saved.
+        """
+        with open(json_file_path, "w", encoding="utf-8") as writer:
+            writer.write(self.to_json_string())
+
+
+class FrozenDict(OrderedDict):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        for key, value in self.items():
+            setattr(self, key, value)
+
+        self.__frozen = True
+
+    def __delitem__(self, *args, **kwargs):
+        raise Exception(f"You cannot use ``__delitem__`` on a {self.__class__.__name__} instance.")
+
+    def setdefault(self, *args, **kwargs):
+        raise Exception(f"You cannot use ``setdefault`` on a {self.__class__.__name__} instance.")
+
+    def pop(self, *args, **kwargs):
+        raise Exception(f"You cannot use ``pop`` on a {self.__class__.__name__} instance.")
+
+    def update(self, *args, **kwargs):
+        raise Exception(f"You cannot use ``update`` on a {self.__class__.__name__} instance.")
+
+    def __setattr__(self, name, value):
+        if hasattr(self, "__frozen") and self.__frozen:
+            raise Exception(f"You cannot use ``__setattr__`` on a {self.__class__.__name__} instance.")
+        super().__setattr__(name, value)
+
+    def __setitem__(self, name, value):
+        if hasattr(self, "__frozen") and self.__frozen:
+            raise Exception(f"You cannot use ``__setattr__`` on a {self.__class__.__name__} instance.")
+        super().__setitem__(name, value)
+
+
+def register_to_config(init):
+    r"""
+    Decorator to apply on the init of classes inheriting from [`ConfigMixin`] so that all the arguments are
+    automatically sent to `self.register_for_config`. To ignore a specific argument accepted by the init but that
+    shouldn't be registered in the config, use the `ignore_for_config` class variable
+
+    Warning: Once decorated, all private arguments (beginning with an underscore) are trashed and not sent to the init!
+    """
+
+    @functools.wraps(init)
+    def inner_init(self, *args, **kwargs):
+        # Ignore private kwargs in the init.
+        init_kwargs = {k: v for k, v in kwargs.items() if not k.startswith("_")}
+        init(self, *args, **init_kwargs)
+        if not isinstance(self, ConfigMixin):
+            raise RuntimeError(
+                f"`@register_for_config` was applied to {self.__class__.__name__} init method, but this class does "
+                "not inherit from `ConfigMixin`."
+            )
+
+        ignore = getattr(self, "ignore_for_config", [])
+        # Get positional arguments aligned with kwargs
+        new_kwargs = {}
+        signature = inspect.signature(init)
+        parameters = {
+            name: p.default for i, (name, p) in enumerate(signature.parameters.items()) if i > 0 and name not in ignore
+        }
+        for arg, name in zip(args, parameters.keys()):
+            new_kwargs[name] = arg
+
+        # Then add all kwargs
+        new_kwargs.update(
+            {
+                k: init_kwargs.get(k, default)
+                for k, default in parameters.items()
+                if k not in ignore and k not in new_kwargs
+            }
+        )
+        getattr(self, "register_to_config")(**new_kwargs)
+
+    return inner_init

diffusers/dependency_versions_check.py

@@ -0,0 +1,47 @@
+# Copyright 2020 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import sys
+
+from .dependency_versions_table import deps
+from .utils.versions import require_version, require_version_core
+
+
+# define which module versions we always want to check at run time
+# (usually the ones defined in `install_requires` in setup.py)
+#
+# order specific notes:
+# - tqdm must be checked before tokenizers
+
+pkgs_to_check_at_runtime = "python tqdm regex requests packaging filelock numpy tokenizers".split()
+if sys.version_info < (3, 7):
+    pkgs_to_check_at_runtime.append("dataclasses")
+if sys.version_info < (3, 8):
+    pkgs_to_check_at_runtime.append("importlib_metadata")
+
+for pkg in pkgs_to_check_at_runtime:
+    if pkg in deps:
+        if pkg == "tokenizers":
+            # must be loaded here, or else tqdm check may fail
+            from .utils import is_tokenizers_available
+
+            if not is_tokenizers_available():
+                continue  # not required, check version only if installed
+
+        require_version_core(deps[pkg])
+    else:
+        raise ValueError(f"can't find {pkg} in {deps.keys()}, check dependency_versions_table.py")
+
+
+def dep_version_check(pkg, hint=None):
+    require_version(deps[pkg], hint)

diffusers/dependency_versions_table.py

@@ -0,0 +1,26 @@
+# THIS FILE HAS BEEN AUTOGENERATED. To update:
+# 1. modify the `_deps` dict in setup.py
+# 2. run `make deps_table_update``
+deps = {
+    "Pillow": "Pillow",
+    "accelerate": "accelerate>=0.11.0",
+    "black": "black==22.3",
+    "datasets": "datasets",
+    "filelock": "filelock",
+    "flake8": "flake8>=3.8.3",
+    "hf-doc-builder": "hf-doc-builder>=0.3.0",
+    "huggingface-hub": "huggingface-hub>=0.8.1",
+    "importlib_metadata": "importlib_metadata",
+    "isort": "isort>=5.5.4",
+    "modelcards": "modelcards==0.1.4",
+    "numpy": "numpy",
+    "pytest": "pytest",
+    "pytest-timeout": "pytest-timeout",
+    "pytest-xdist": "pytest-xdist",
+    "scipy": "scipy",
+    "regex": "regex!=2019.12.17",
+    "requests": "requests",
+    "tensorboard": "tensorboard",
+    "torch": "torch>=1.4",
+    "transformers": "transformers>=4.21.0",
+}

diffusers/dynamic_modules_utils.py

@@ -0,0 +1,335 @@
+# coding=utf-8
+# Copyright 2021 The HuggingFace Inc. team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Utilities to dynamically load objects from the Hub."""
+
+import importlib
+import os
+import re
+import shutil
+import sys
+from pathlib import Path
+from typing import Dict, Optional, Union
+
+from huggingface_hub import cached_download
+
+from .utils import DIFFUSERS_DYNAMIC_MODULE_NAME, HF_MODULES_CACHE, logging
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+def init_hf_modules():
+    """
+    Creates the cache directory for modules with an init, and adds it to the Python path.
+    """
+    # This function has already been executed if HF_MODULES_CACHE already is in the Python path.
+    if HF_MODULES_CACHE in sys.path:
+        return
+
+    sys.path.append(HF_MODULES_CACHE)
+    os.makedirs(HF_MODULES_CACHE, exist_ok=True)
+    init_path = Path(HF_MODULES_CACHE) / "__init__.py"
+    if not init_path.exists():
+        init_path.touch()
+
+
+def create_dynamic_module(name: Union[str, os.PathLike]):
+    """
+    Creates a dynamic module in the cache directory for modules.
+    """
+    init_hf_modules()
+    dynamic_module_path = Path(HF_MODULES_CACHE) / name
+    # If the parent module does not exist yet, recursively create it.
+    if not dynamic_module_path.parent.exists():
+        create_dynamic_module(dynamic_module_path.parent)
+    os.makedirs(dynamic_module_path, exist_ok=True)
+    init_path = dynamic_module_path / "__init__.py"
+    if not init_path.exists():
+        init_path.touch()
+
+
+def get_relative_imports(module_file):
+    """
+    Get the list of modules that are relatively imported in a module file.
+
+    Args:
+        module_file (`str` or `os.PathLike`): The module file to inspect.
+    """
+    with open(module_file, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    # Imports of the form `import .xxx`
+    relative_imports = re.findall("^\s*import\s+\.(\S+)\s*$", content, flags=re.MULTILINE)
+    # Imports of the form `from .xxx import yyy`
+    relative_imports += re.findall("^\s*from\s+\.(\S+)\s+import", content, flags=re.MULTILINE)
+    # Unique-ify
+    return list(set(relative_imports))
+
+
+def get_relative_import_files(module_file):
+    """
+    Get the list of all files that are needed for a given module. Note that this function recurses through the relative
+    imports (if a imports b and b imports c, it will return module files for b and c).
+
+    Args:
+        module_file (`str` or `os.PathLike`): The module file to inspect.
+    """
+    no_change = False
+    files_to_check = [module_file]
+    all_relative_imports = []
+
+    # Let's recurse through all relative imports
+    while not no_change:
+        new_imports = []
+        for f in files_to_check:
+            new_imports.extend(get_relative_imports(f))
+
+        module_path = Path(module_file).parent
+        new_import_files = [str(module_path / m) for m in new_imports]
+        new_import_files = [f for f in new_import_files if f not in all_relative_imports]
+        files_to_check = [f"{f}.py" for f in new_import_files]
+
+        no_change = len(new_import_files) == 0
+        all_relative_imports.extend(files_to_check)
+
+    return all_relative_imports
+
+
+def check_imports(filename):
+    """
+    Check if the current Python environment contains all the libraries that are imported in a file.
+    """
+    with open(filename, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    # Imports of the form `import xxx`
+    imports = re.findall("^\s*import\s+(\S+)\s*$", content, flags=re.MULTILINE)
+    # Imports of the form `from xxx import yyy`
+    imports += re.findall("^\s*from\s+(\S+)\s+import", content, flags=re.MULTILINE)
+    # Only keep the top-level module
+    imports = [imp.split(".")[0] for imp in imports if not imp.startswith(".")]
+
+    # Unique-ify and test we got them all
+    imports = list(set(imports))
+    missing_packages = []
+    for imp in imports:
+        try:
+            importlib.import_module(imp)
+        except ImportError:
+            missing_packages.append(imp)
+
+    if len(missing_packages) > 0:
+        raise ImportError(
+            "This modeling file requires the following packages that were not found in your environment: "
+            f"{', '.join(missing_packages)}. Run `pip install {' '.join(missing_packages)}`"
+        )
+
+    return get_relative_imports(filename)
+
+
+def get_class_in_module(class_name, module_path):
+    """
+    Import a module on the cache directory for modules and extract a class from it.
+    """
+    module_path = module_path.replace(os.path.sep, ".")
+    module = importlib.import_module(module_path)
+    return getattr(module, class_name)
+
+
+def get_cached_module_file(
+    pretrained_model_name_or_path: Union[str, os.PathLike],
+    module_file: str,
+    cache_dir: Optional[Union[str, os.PathLike]] = None,
+    force_download: bool = False,
+    resume_download: bool = False,
+    proxies: Optional[Dict[str, str]] = None,
+    use_auth_token: Optional[Union[bool, str]] = None,
+    revision: Optional[str] = None,
+    local_files_only: bool = False,
+):
+    """
+    Prepares Downloads a module from a local folder or a distant repo and returns its path inside the cached
+    Transformers module.
+
+    Args:
+        pretrained_model_name_or_path (`str` or `os.PathLike`):
+            This can be either:
+
+            - a string, the *model id* of a pretrained model configuration hosted inside a model repo on
+              huggingface.co. Valid model ids can be located at the root-level, like `bert-base-uncased`, or namespaced
+              under a user or organization name, like `dbmdz/bert-base-german-cased`.
+            - a path to a *directory* containing a configuration file saved using the
+              [`~PreTrainedTokenizer.save_pretrained`] method, e.g., `./my_model_directory/`.
+
+        module_file (`str`):
+            The name of the module file containing the class to look for.
+        cache_dir (`str` or `os.PathLike`, *optional*):
+            Path to a directory in which a downloaded pretrained model configuration should be cached if the standard
+            cache should not be used.
+        force_download (`bool`, *optional*, defaults to `False`):
+            Whether or not to force to (re-)download the configuration files and override the cached versions if they
+            exist.
+        resume_download (`bool`, *optional*, defaults to `False`):
+            Whether or not to delete incompletely received file. Attempts to resume the download if such a file exists.
+        proxies (`Dict[str, str]`, *optional*):
+            A dictionary of proxy servers to use by protocol or endpoint, e.g., `{'http': 'foo.bar:3128',
+            'http://hostname': 'foo.bar:4012'}.` The proxies are used on each request.
+        use_auth_token (`str` or *bool*, *optional*):
+            The token to use as HTTP bearer authorization for remote files. If `True`, will use the token generated
+            when running `transformers-cli login` (stored in `~/.huggingface`).
+        revision (`str`, *optional*, defaults to `"main"`):
+            The specific model version to use. It can be a branch name, a tag name, or a commit id, since we use a
+            git-based system for storing models and other artifacts on huggingface.co, so `revision` can be any
+            identifier allowed by git.
+        local_files_only (`bool`, *optional*, defaults to `False`):
+            If `True`, will only try to load the tokenizer configuration from local files.
+
+    <Tip>
+
+    Passing `use_auth_token=True` is required when you want to use a private model.
+
+    </Tip>
+
+    Returns:
+        `str`: The path to the module inside the cache.
+    """
+    # Download and cache module_file from the repo `pretrained_model_name_or_path` of grab it if it's a local file.
+    pretrained_model_name_or_path = str(pretrained_model_name_or_path)
+    module_file_or_url = os.path.join(pretrained_model_name_or_path, module_file)
+    submodule = "local"
+
+    if os.path.isfile(module_file_or_url):
+        resolved_module_file = module_file_or_url
+    else:
+        try:
+            # Load from URL or cache if already cached
+            resolved_module_file = cached_download(
+                module_file_or_url,
+                cache_dir=cache_dir,
+                force_download=force_download,
+                proxies=proxies,
+                resume_download=resume_download,
+                local_files_only=local_files_only,
+                use_auth_token=use_auth_token,
+            )
+
+        except EnvironmentError:
+            logger.error(f"Could not locate the {module_file} inside {pretrained_model_name_or_path}.")
+            raise
+
+    # Check we have all the requirements in our environment
+    modules_needed = check_imports(resolved_module_file)
+
+    # Now we move the module inside our cached dynamic modules.
+    full_submodule = DIFFUSERS_DYNAMIC_MODULE_NAME + os.path.sep + submodule
+    create_dynamic_module(full_submodule)
+    submodule_path = Path(HF_MODULES_CACHE) / full_submodule
+    # We always copy local files (we could hash the file to see if there was a change, and give them the name of
+    # that hash, to only copy when there is a modification but it seems overkill for now).
+    # The only reason we do the copy is to avoid putting too many folders in sys.path.
+    shutil.copy(resolved_module_file, submodule_path / module_file)
+    for module_needed in modules_needed:
+        module_needed = f"{module_needed}.py"
+        shutil.copy(os.path.join(pretrained_model_name_or_path, module_needed), submodule_path / module_needed)
+    return os.path.join(full_submodule, module_file)
+
+
+def get_class_from_dynamic_module(
+    pretrained_model_name_or_path: Union[str, os.PathLike],
+    module_file: str,
+    class_name: str,
+    cache_dir: Optional[Union[str, os.PathLike]] = None,
+    force_download: bool = False,
+    resume_download: bool = False,
+    proxies: Optional[Dict[str, str]] = None,
+    use_auth_token: Optional[Union[bool, str]] = None,
+    revision: Optional[str] = None,
+    local_files_only: bool = False,
+    **kwargs,
+):
+    """
+    Extracts a class from a module file, present in the local folder or repository of a model.
+
+    <Tip warning={true}>
+
+    Calling this function will execute the code in the module file found locally or downloaded from the Hub. It should
+    therefore only be called on trusted repos.
+
+    </Tip>
+
+    Args:
+        pretrained_model_name_or_path (`str` or `os.PathLike`):
+            This can be either:
+
+            - a string, the *model id* of a pretrained model configuration hosted inside a model repo on
+              huggingface.co. Valid model ids can be located at the root-level, like `bert-base-uncased`, or namespaced
+              under a user or organization name, like `dbmdz/bert-base-german-cased`.
+            - a path to a *directory* containing a configuration file saved using the
+              [`~PreTrainedTokenizer.save_pretrained`] method, e.g., `./my_model_directory/`.
+
+        module_file (`str`):
+            The name of the module file containing the class to look for.
+        class_name (`str`):
+            The name of the class to import in the module.
+        cache_dir (`str` or `os.PathLike`, *optional*):
+            Path to a directory in which a downloaded pretrained model configuration should be cached if the standard
+            cache should not be used.
+        force_download (`bool`, *optional*, defaults to `False`):
+            Whether or not to force to (re-)download the configuration files and override the cached versions if they
+            exist.
+        resume_download (`bool`, *optional*, defaults to `False`):
+            Whether or not to delete incompletely received file. Attempts to resume the download if such a file exists.
+        proxies (`Dict[str, str]`, *optional*):
+            A dictionary of proxy servers to use by protocol or endpoint, e.g., `{'http': 'foo.bar:3128',
+            'http://hostname': 'foo.bar:4012'}.` The proxies are used on each request.
+        use_auth_token (`str` or `bool`, *optional*):
+            The token to use as HTTP bearer authorization for remote files. If `True`, will use the token generated
+            when running `transformers-cli login` (stored in `~/.huggingface`).
+        revision (`str`, *optional*, defaults to `"main"`):
+            The specific model version to use. It can be a branch name, a tag name, or a commit id, since we use a
+            git-based system for storing models and other artifacts on huggingface.co, so `revision` can be any
+            identifier allowed by git.
+        local_files_only (`bool`, *optional*, defaults to `False`):
+            If `True`, will only try to load the tokenizer configuration from local files.
+
+    <Tip>
+
+    Passing `use_auth_token=True` is required when you want to use a private model.
+
+    </Tip>
+
+    Returns:
+        `type`: The class, dynamically imported from the module.
+
+    Examples:
+
+    ```python
+    # Download module `modeling.py` from huggingface.co and cache then extract the class `MyBertModel` from this
+    # module.
+    cls = get_class_from_dynamic_module("sgugger/my-bert-model", "modeling.py", "MyBertModel")
+    ```"""
+    # And lastly we get the class inside our newly created module
+    final_module = get_cached_module_file(
+        pretrained_model_name_or_path,
+        module_file,
+        cache_dir=cache_dir,
+        force_download=force_download,
+        resume_download=resume_download,
+        proxies=proxies,
+        use_auth_token=use_auth_token,
+        revision=revision,
+        local_files_only=local_files_only,
+    )
+    return get_class_in_module(class_name, final_module.replace(".py", ""))

diffusers/hub_utils.py

@@ -0,0 +1,197 @@
+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import os
+import shutil
+from pathlib import Path
+from typing import Optional
+
+from huggingface_hub import HfFolder, Repository, whoami
+
+from .pipeline_utils import DiffusionPipeline
+from .utils import is_modelcards_available, logging
+
+
+if is_modelcards_available():
+    from modelcards import CardData, ModelCard
+
+
+logger = logging.get_logger(__name__)
+
+
+MODEL_CARD_TEMPLATE_PATH = Path(__file__).parent / "utils" / "model_card_template.md"
+
+
+def get_full_repo_name(model_id: str, organization: Optional[str] = None, token: Optional[str] = None):
+    if token is None:
+        token = HfFolder.get_token()
+    if organization is None:
+        username = whoami(token)["name"]
+        return f"{username}/{model_id}"
+    else:
+        return f"{organization}/{model_id}"
+
+
+def init_git_repo(args, at_init: bool = False):
+    """
+    Args:
+    Initializes a git repo in `args.hub_model_id`.
+        at_init (`bool`, *optional*, defaults to `False`):
+            Whether this function is called before any training or not. If `self.args.overwrite_output_dir` is `True`
+            and `at_init` is `True`, the path to the repo (which is `self.args.output_dir`) might be wiped out.
+    """
+    if hasattr(args, "local_rank") and args.local_rank not in [-1, 0]:
+        return
+    hub_token = args.hub_token if hasattr(args, "hub_token") else None
+    use_auth_token = True if hub_token is None else hub_token
+    if not hasattr(args, "hub_model_id") or args.hub_model_id is None:
+        repo_name = Path(args.output_dir).absolute().name
+    else:
+        repo_name = args.hub_model_id
+    if "/" not in repo_name:
+        repo_name = get_full_repo_name(repo_name, token=hub_token)
+
+    try:
+        repo = Repository(
+            args.output_dir,
+            clone_from=repo_name,
+            use_auth_token=use_auth_token,
+            private=args.hub_private_repo,
+        )
+    except EnvironmentError:
+        if args.overwrite_output_dir and at_init:
+            # Try again after wiping output_dir
+            shutil.rmtree(args.output_dir)
+            repo = Repository(
+                args.output_dir,
+                clone_from=repo_name,
+                use_auth_token=use_auth_token,
+            )
+        else:
+            raise
+
+    repo.git_pull()
+
+    # By default, ignore the checkpoint folders
+    if not os.path.exists(os.path.join(args.output_dir, ".gitignore")):
+        with open(os.path.join(args.output_dir, ".gitignore"), "w", encoding="utf-8") as writer:
+            writer.writelines(["checkpoint-*/"])
+
+    return repo
+
+
+def push_to_hub(
+    args,
+    pipeline: DiffusionPipeline,
+    repo: Repository,
+    commit_message: Optional[str] = "End of training",
+    blocking: bool = True,
+    **kwargs,
+) -> str:
+    """
+    Parameters:
+    Upload *self.model* and *self.tokenizer* to the 🤗 model hub on the repo *self.args.hub_model_id*.
+        commit_message (`str`, *optional*, defaults to `"End of training"`):
+            Message to commit while pushing.
+        blocking (`bool`, *optional*, defaults to `True`):
+            Whether the function should return only when the `git push` has finished.
+        kwargs:
+            Additional keyword arguments passed along to [`create_model_card`].
+    Returns:
+        The url of the commit of your model in the given repository if `blocking=False`, a tuple with the url of the
+        commit and an object to track the progress of the commit if `blocking=True`
+    """
+
+    if not hasattr(args, "hub_model_id") or args.hub_model_id is None:
+        model_name = Path(args.output_dir).name
+    else:
+        model_name = args.hub_model_id.split("/")[-1]
+
+    output_dir = args.output_dir
+    os.makedirs(output_dir, exist_ok=True)
+    logger.info(f"Saving pipeline checkpoint to {output_dir}")
+    pipeline.save_pretrained(output_dir)
+
+    # Only push from one node.
+    if hasattr(args, "local_rank") and args.local_rank not in [-1, 0]:
+        return
+
+    # Cancel any async push in progress if blocking=True. The commits will all be pushed together.
+    if (
+        blocking
+        and len(repo.command_queue) > 0
+        and repo.command_queue[-1] is not None
+        and not repo.command_queue[-1].is_done
+    ):
+        repo.command_queue[-1]._process.kill()
+
+    git_head_commit_url = repo.push_to_hub(commit_message=commit_message, blocking=blocking, auto_lfs_prune=True)
+    # push separately the model card to be independent from the rest of the model
+    create_model_card(args, model_name=model_name)
+    try:
+        repo.push_to_hub(commit_message="update model card README.md", blocking=blocking, auto_lfs_prune=True)
+    except EnvironmentError as exc:
+        logger.error(f"Error pushing update to the model card. Please read logs and retry.\n${exc}")
+
+    return git_head_commit_url
+
+
+def create_model_card(args, model_name):
+    if not is_modelcards_available:
+        raise ValueError(
+            "Please make sure to have `modelcards` installed when using the `create_model_card` function. You can"
+            " install the package with `pip install modelcards`."
+        )
+
+    if hasattr(args, "local_rank") and args.local_rank not in [-1, 0]:
+        return
+
+    hub_token = args.hub_token if hasattr(args, "hub_token") else None
+    repo_name = get_full_repo_name(model_name, token=hub_token)
+
+    model_card = ModelCard.from_template(
+        card_data=CardData(  # Card metadata object that will be converted to YAML block
+            language="en",
+            license="apache-2.0",
+            library_name="diffusers",
+            tags=[],
+            datasets=args.dataset_name,
+            metrics=[],
+        ),
+        template_path=MODEL_CARD_TEMPLATE_PATH,
+        model_name=model_name,
+        repo_name=repo_name,
+        dataset_name=args.dataset_name if hasattr(args, "dataset_name") else None,
+        learning_rate=args.learning_rate,
+        train_batch_size=args.train_batch_size,
+        eval_batch_size=args.eval_batch_size,
+        gradient_accumulation_steps=args.gradient_accumulation_steps
+        if hasattr(args, "gradient_accumulation_steps")
+        else None,
+        adam_beta1=args.adam_beta1 if hasattr(args, "adam_beta1") else None,
+        adam_beta2=args.adam_beta2 if hasattr(args, "adam_beta2") else None,
+        adam_weight_decay=args.adam_weight_decay if hasattr(args, "adam_weight_decay") else None,
+        adam_epsilon=args.adam_epsilon if hasattr(args, "adam_epsilon") else None,
+        lr_scheduler=args.lr_scheduler if hasattr(args, "lr_scheduler") else None,
+        lr_warmup_steps=args.lr_warmup_steps if hasattr(args, "lr_warmup_steps") else None,
+        ema_inv_gamma=args.ema_inv_gamma if hasattr(args, "ema_inv_gamma") else None,
+        ema_power=args.ema_power if hasattr(args, "ema_power") else None,
+        ema_max_decay=args.ema_max_decay if hasattr(args, "ema_max_decay") else None,
+        mixed_precision=args.mixed_precision,
+    )
+
+    card_path = os.path.join(args.output_dir, "README.md")
+    model_card.save(card_path)

diffusers/modeling_utils.py

@@ -0,0 +1,542 @@
+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+# Copyright (c) 2022, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+from typing import Callable, List, Optional, Tuple, Union
+
+import torch
+from torch import Tensor, device
+
+from huggingface_hub import hf_hub_download
+from huggingface_hub.utils import EntryNotFoundError, RepositoryNotFoundError, RevisionNotFoundError
+from requests import HTTPError
+
+from .utils import CONFIG_NAME, DIFFUSERS_CACHE, HUGGINGFACE_CO_RESOLVE_ENDPOINT, logging
+
+
+WEIGHTS_NAME = "diffusion_pytorch_model.bin"
+
+
+logger = logging.get_logger(__name__)
+
+
+def get_parameter_device(parameter: torch.nn.Module):
+    try:
+        return next(parameter.parameters()).device
+    except StopIteration:
+        # For torch.nn.DataParallel compatibility in PyTorch 1.5
+
+        def find_tensor_attributes(module: torch.nn.Module) -> List[Tuple[str, Tensor]]:
+            tuples = [(k, v) for k, v in module.__dict__.items() if torch.is_tensor(v)]
+            return tuples
+
+        gen = parameter._named_members(get_members_fn=find_tensor_attributes)
+        first_tuple = next(gen)
+        return first_tuple[1].device
+
+
+def get_parameter_dtype(parameter: torch.nn.Module):
+    try:
+        return next(parameter.parameters()).dtype
+    except StopIteration:
+        # For torch.nn.DataParallel compatibility in PyTorch 1.5
+
+        def find_tensor_attributes(module: torch.nn.Module) -> List[Tuple[str, Tensor]]:
+            tuples = [(k, v) for k, v in module.__dict__.items() if torch.is_tensor(v)]
+            return tuples
+
+        gen = parameter._named_members(get_members_fn=find_tensor_attributes)
+        first_tuple = next(gen)
+        return first_tuple[1].dtype
+
+
+def load_state_dict(checkpoint_file: Union[str, os.PathLike]):
+    """
+    Reads a PyTorch checkpoint file, returning properly formatted errors if they arise.
+    """
+    try:
+        return torch.load(checkpoint_file, map_location="cpu")
+    except Exception as e:
+        try:
+            with open(checkpoint_file) as f:
+                if f.read().startswith("version"):
+                    raise OSError(
+                        "You seem to have cloned a repository without having git-lfs installed. Please install "
+                        "git-lfs and run `git lfs install` followed by `git lfs pull` in the folder "
+                        "you cloned."
+                    )
+                else:
+                    raise ValueError(
+                        f"Unable to locate the file {checkpoint_file} which is necessary to load this pretrained "
+                        "model. Make sure you have saved the model properly."
+                    ) from e
+        except (UnicodeDecodeError, ValueError):
+            raise OSError(
+                f"Unable to load weights from pytorch checkpoint file for '{checkpoint_file}' "
+                f"at '{checkpoint_file}'. "
+                "If you tried to load a PyTorch model from a TF 2.0 checkpoint, please set from_tf=True."
+            )
+
+
+def _load_state_dict_into_model(model_to_load, state_dict):
+    # Convert old format to new format if needed from a PyTorch state_dict
+    # copy state_dict so _load_from_state_dict can modify it
+    state_dict = state_dict.copy()
+    error_msgs = []
+
+    # PyTorch's `_load_from_state_dict` does not copy parameters in a module's descendants
+    # so we need to apply the function recursively.
+    def load(module: torch.nn.Module, prefix=""):
+        args = (state_dict, prefix, {}, True, [], [], error_msgs)
+        module._load_from_state_dict(*args)
+
+        for name, child in module._modules.items():
+            if child is not None:
+                load(child, prefix + name + ".")
+
+    load(model_to_load)
+
+    return error_msgs
+
+
+class ModelMixin(torch.nn.Module):
+    r"""
+    Base class for all models.
+
+    [`ModelMixin`] takes care of storing the configuration of the models and handles methods for loading, downloading
+    and saving models.
+
+        - **config_name** ([`str`]) -- A filename under which the model should be stored when calling
+          [`~modeling_utils.ModelMixin.save_pretrained`].
+    """
+    config_name = CONFIG_NAME
+    _automatically_saved_args = ["_diffusers_version", "_class_name", "_name_or_path"]
+
+    def __init__(self):
+        super().__init__()
+
+    def save_pretrained(
+        self,
+        save_directory: Union[str, os.PathLike],
+        is_main_process: bool = True,
+        save_function: Callable = torch.save,
+    ):
+        """
+        Save a model and its configuration file to a directory, so that it can be re-loaded using the
+        `[`~modeling_utils.ModelMixin.from_pretrained`]` class method.
+
+        Arguments:
+            save_directory (`str` or `os.PathLike`):
+                Directory to which to save. Will be created if it doesn't exist.
+            is_main_process (`bool`, *optional*, defaults to `True`):
+                Whether the process calling this is the main process or not. Useful when in distributed training like
+                TPUs and need to call this function on all processes. In this case, set `is_main_process=True` only on
+                the main process to avoid race conditions.
+            save_function (`Callable`):
+                The function to use to save the state dictionary. Useful on distributed training like TPUs when one
+                need to replace `torch.save` by another method.
+        """
+        if os.path.isfile(save_directory):
+            logger.error(f"Provided path ({save_directory}) should be a directory, not a file")
+            return
+
+        os.makedirs(save_directory, exist_ok=True)
+
+        model_to_save = self
+
+        # Attach architecture to the config
+        # Save the config
+        if is_main_process:
+            model_to_save.save_config(save_directory)
+
+        # Save the model
+        state_dict = model_to_save.state_dict()
+
+        # Clean the folder from a previous save
+        for filename in os.listdir(save_directory):
+            full_filename = os.path.join(save_directory, filename)
+            # If we have a shard file that is not going to be replaced, we delete it, but only from the main process
+            # in distributed settings to avoid race conditions.
+            if filename.startswith(WEIGHTS_NAME[:-4]) and os.path.isfile(full_filename) and is_main_process:
+                os.remove(full_filename)
+
+        # Save the model
+        save_function(state_dict, os.path.join(save_directory, WEIGHTS_NAME))
+
+        logger.info(f"Model weights saved in {os.path.join(save_directory, WEIGHTS_NAME)}")
+
+    @classmethod
+    def from_pretrained(cls, pretrained_model_name_or_path: Optional[Union[str, os.PathLike]], **kwargs):
+        r"""
+        Instantiate a pretrained pytorch model from a pre-trained model configuration.
+
+        The model is set in evaluation mode by default using `model.eval()` (Dropout modules are deactivated). To train
+        the model, you should first set it back in training mode with `model.train()`.
+
+        The warning *Weights from XXX not initialized from pretrained model* means that the weights of XXX do not come
+        pretrained with the rest of the model. It is up to you to train those weights with a downstream fine-tuning
+        task.
+
+        The warning *Weights from XXX not used in YYY* means that the layer XXX is not used by YYY, therefore those
+        weights are discarded.
+
+        Parameters:
+            pretrained_model_name_or_path (`str` or `os.PathLike`, *optional*):
+                Can be either:
+
+                    - A string, the *model id* of a pretrained model hosted inside a model repo on huggingface.co.
+                      Valid model ids should have an organization name, like `google/ddpm-celebahq-256`.
+                    - A path to a *directory* containing model weights saved using [`~ModelMixin.save_config`], e.g.,
+                      `./my_model_directory/`.
+
+            cache_dir (`Union[str, os.PathLike]`, *optional*):
+                Path to a directory in which a downloaded pretrained model configuration should be cached if the
+                standard cache should not be used.
+            torch_dtype (`str` or `torch.dtype`, *optional*):
+                Override the default `torch.dtype` and load the model under this dtype. If `"auto"` is passed the dtype
+                will be automatically derived from the model's weights.
+            force_download (`bool`, *optional*, defaults to `False`):
+                Whether or not to force the (re-)download of the model weights and configuration files, overriding the
+                cached versions if they exist.
+            resume_download (`bool`, *optional*, defaults to `False`):
+                Whether or not to delete incompletely received files. Will attempt to resume the download if such a
+                file exists.
+            proxies (`Dict[str, str]`, *optional*):
+                A dictionary of proxy servers to use by protocol or endpoint, e.g., `{'http': 'foo.bar:3128',
+                'http://hostname': 'foo.bar:4012'}`. The proxies are used on each request.
+            output_loading_info(`bool`, *optional*, defaults to `False`):
+                Whether ot not to also return a dictionary containing missing keys, unexpected keys and error messages.
+            local_files_only(`bool`, *optional*, defaults to `False`):
+                Whether or not to only look at local files (i.e., do not try to download the model).
+            use_auth_token (`str` or *bool*, *optional*):
+                The token to use as HTTP bearer authorization for remote files. If `True`, will use the token generated
+                when running `diffusers-cli login` (stored in `~/.huggingface`).
+            revision (`str`, *optional*, defaults to `"main"`):
+                The specific model version to use. It can be a branch name, a tag name, or a commit id, since we use a
+                git-based system for storing models and other artifacts on huggingface.co, so `revision` can be any
+                identifier allowed by git.
+            mirror (`str`, *optional*):
+                Mirror source to accelerate downloads in China. If you are from China and have an accessibility
+                problem, you can set this option to resolve it. Note that we do not guarantee the timeliness or safety.
+                Please refer to the mirror site for more information.
+
+        <Tip>
+
+        Passing `use_auth_token=True`` is required when you want to use a private model.
+
+        </Tip>
+
+        <Tip>
+
+        Activate the special ["offline-mode"](https://huggingface.co/diffusers/installation.html#offline-mode) to use
+        this method in a firewalled environment.
+
+        </Tip>
+
+        """
+        cache_dir = kwargs.pop("cache_dir", DIFFUSERS_CACHE)
+        ignore_mismatched_sizes = kwargs.pop("ignore_mismatched_sizes", False)
+        force_download = kwargs.pop("force_download", False)
+        resume_download = kwargs.pop("resume_download", False)
+        proxies = kwargs.pop("proxies", None)
+        output_loading_info = kwargs.pop("output_loading_info", False)
+        local_files_only = kwargs.pop("local_files_only", False)
+        use_auth_token = kwargs.pop("use_auth_token", None)
+        revision = kwargs.pop("revision", None)
+        from_auto_class = kwargs.pop("_from_auto", False)
+        torch_dtype = kwargs.pop("torch_dtype", None)
+        subfolder = kwargs.pop("subfolder", None)
+
+        user_agent = {"file_type": "model", "framework": "pytorch", "from_auto_class": from_auto_class}
+
+        # Load config if we don't provide a configuration
+        config_path = pretrained_model_name_or_path
+        model, unused_kwargs = cls.from_config(
+            config_path,
+            cache_dir=cache_dir,
+            return_unused_kwargs=True,
+            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,
+            **kwargs,
+        )
+
+        if torch_dtype is not None and not isinstance(torch_dtype, torch.dtype):
+            raise ValueError(
+                f"{torch_dtype} needs to be of type `torch.dtype`, e.g. `torch.float16`, but is {type(torch_dtype)}."
+            )
+        elif torch_dtype is not None:
+            model = model.to(torch_dtype)
+
+        model.register_to_config(_name_or_path=pretrained_model_name_or_path)
+        # This variable will flag if we're loading a sharded checkpoint. In this case the archive file is just the
+        # Load model
+        pretrained_model_name_or_path = str(pretrained_model_name_or_path)
+        if os.path.isdir(pretrained_model_name_or_path):
+            if os.path.isfile(os.path.join(pretrained_model_name_or_path, WEIGHTS_NAME)):
+                # Load from a PyTorch checkpoint
+                model_file = os.path.join(pretrained_model_name_or_path, WEIGHTS_NAME)
+            elif subfolder is not None and os.path.isfile(
+                os.path.join(pretrained_model_name_or_path, subfolder, WEIGHTS_NAME)
+            ):
+                model_file = os.path.join(pretrained_model_name_or_path, subfolder, WEIGHTS_NAME)
+            else:
+                raise EnvironmentError(
+                    f"Error no file named {WEIGHTS_NAME} found in directory {pretrained_model_name_or_path}."
+                )
+        else:
+            try:
+                # Load from URL or cache if already cached
+                model_file = hf_hub_download(
+                    pretrained_model_name_or_path,
+                    filename=WEIGHTS_NAME,
+                    cache_dir=cache_dir,
+                    force_download=force_download,
+                    proxies=proxies,
+                    resume_download=resume_download,
+                    local_files_only=local_files_only,
+                    use_auth_token=use_auth_token,
+                    user_agent=user_agent,
+                    subfolder=subfolder,
+                    revision=revision,
+                )
+
+            except RepositoryNotFoundError:
+                raise EnvironmentError(
+                    f"{pretrained_model_name_or_path} is not a local folder and is not a valid model identifier "
+                    "listed on 'https://huggingface.co/models'\nIf this is a private repository, make sure to pass a "
+                    "token having permission to this repo with `use_auth_token` or log in with `huggingface-cli "
+                    "login` and pass `use_auth_token=True`."
+                )
+            except RevisionNotFoundError:
+                raise EnvironmentError(
+                    f"{revision} is not a valid git identifier (branch name, tag name or commit id) that exists for "
+                    "this model name. Check the model page at "
+                    f"'https://huggingface.co/{pretrained_model_name_or_path}' for available revisions."
+                )
+            except EntryNotFoundError:
+                raise EnvironmentError(
+                    f"{pretrained_model_name_or_path} does not appear to have a file named {WEIGHTS_NAME}."
+                )
+            except HTTPError as err:
+                raise EnvironmentError(
+                    "There was a specific connection error when trying to load"
+                    f" {pretrained_model_name_or_path}:\n{err}"
+                )
+            except ValueError:
+                raise EnvironmentError(
+                    f"We couldn't connect to '{HUGGINGFACE_CO_RESOLVE_ENDPOINT}' to load this model, couldn't find it"
+                    f" in the cached files and it looks like {pretrained_model_name_or_path} is not the path to a"
+                    f" directory containing a file named {WEIGHTS_NAME} or"
+                    " \nCheckout your internet connection or see how to run the library in"
+                    " offline mode at 'https://huggingface.co/docs/diffusers/installation#offline-mode'."
+                )
+            except EnvironmentError:
+                raise EnvironmentError(
+                    f"Can't load the model for '{pretrained_model_name_or_path}'. If you were trying to load it from "
+                    "'https://huggingface.co/models', make sure you don't have a local directory with the same name. "
+                    f"Otherwise, make sure '{pretrained_model_name_or_path}' is the correct path to a directory "
+                    f"containing a file named {WEIGHTS_NAME}"
+                )
+
+            # restore default dtype
+        state_dict = load_state_dict(model_file)
+        model, missing_keys, unexpected_keys, mismatched_keys, error_msgs = cls._load_pretrained_model(
+            model,
+            state_dict,
+            model_file,
+            pretrained_model_name_or_path,
+            ignore_mismatched_sizes=ignore_mismatched_sizes,
+        )
+
+        # Set model in evaluation mode to deactivate DropOut modules by default
+        model.eval()
+
+        if output_loading_info:
+            loading_info = {
+                "missing_keys": missing_keys,
+                "unexpected_keys": unexpected_keys,
+                "mismatched_keys": mismatched_keys,
+                "error_msgs": error_msgs,
+            }
+            return model, loading_info
+
+        return model
+
+    @classmethod
+    def _load_pretrained_model(
+        cls,
+        model,
+        state_dict,
+        resolved_archive_file,
+        pretrained_model_name_or_path,
+        ignore_mismatched_sizes=False,
+    ):
+        # Retrieve missing & unexpected_keys
+        model_state_dict = model.state_dict()
+        loaded_keys = [k for k in state_dict.keys()]
+
+        expected_keys = list(model_state_dict.keys())
+
+        original_loaded_keys = loaded_keys
+
+        missing_keys = list(set(expected_keys) - set(loaded_keys))
+        unexpected_keys = list(set(loaded_keys) - set(expected_keys))
+
+        # Make sure we are able to load base models as well as derived models (with heads)
+        model_to_load = model
+
+        def _find_mismatched_keys(
+            state_dict,
+            model_state_dict,
+            loaded_keys,
+            ignore_mismatched_sizes,
+        ):
+            mismatched_keys = []
+            if ignore_mismatched_sizes:
+                for checkpoint_key in loaded_keys:
+                    model_key = checkpoint_key
+
+                    if (
+                        model_key in model_state_dict
+                        and state_dict[checkpoint_key].shape != model_state_dict[model_key].shape
+                    ):
+                        mismatched_keys.append(
+                            (checkpoint_key, state_dict[checkpoint_key].shape, model_state_dict[model_key].shape)
+                        )
+                        del state_dict[checkpoint_key]
+            return mismatched_keys
+
+        if state_dict is not None:
+            # Whole checkpoint
+            mismatched_keys = _find_mismatched_keys(
+                state_dict,
+                model_state_dict,
+                original_loaded_keys,
+                ignore_mismatched_sizes,
+            )
+            error_msgs = _load_state_dict_into_model(model_to_load, state_dict)
+
+        if len(error_msgs) > 0:
+            error_msg = "\n\t".join(error_msgs)
+            if "size mismatch" in error_msg:
+                error_msg += (
+                    "\n\tYou may consider adding `ignore_mismatched_sizes=True` in the model `from_pretrained` method."
+                )
+            raise RuntimeError(f"Error(s) in loading state_dict for {model.__class__.__name__}:\n\t{error_msg}")
+
+        if len(unexpected_keys) > 0:
+            logger.warning(
+                f"Some weights of the model checkpoint at {pretrained_model_name_or_path} were not used when"
+                f" initializing {model.__class__.__name__}: {unexpected_keys}\n- This IS expected if you are"
+                f" initializing {model.__class__.__name__} from the checkpoint of a model trained on another task"
+                " or with another architecture (e.g. initializing a BertForSequenceClassification model from a"
+                " BertForPreTraining model).\n- This IS NOT expected if you are initializing"
+                f" {model.__class__.__name__} from the checkpoint of a model that you expect to be exactly"
+                " identical (initializing a BertForSequenceClassification model from a"
+                " BertForSequenceClassification model)."
+            )
+        else:
+            logger.info(f"All model checkpoint weights were used when initializing {model.__class__.__name__}.\n")
+        if len(missing_keys) > 0:
+            logger.warning(
+                f"Some weights of {model.__class__.__name__} were not initialized from the model checkpoint at"
+                f" {pretrained_model_name_or_path} and are newly initialized: {missing_keys}\nYou should probably"
+                " TRAIN this model on a down-stream task to be able to use it for predictions and inference."
+            )
+        elif len(mismatched_keys) == 0:
+            logger.info(
+                f"All the weights of {model.__class__.__name__} were initialized from the model checkpoint at"
+                f" {pretrained_model_name_or_path}.\nIf your task is similar to the task the model of the"
+                f" checkpoint was trained on, you can already use {model.__class__.__name__} for predictions"
+                " without further training."
+            )
+        if len(mismatched_keys) > 0:
+            mismatched_warning = "\n".join(
+                [
+                    f"- {key}: found shape {shape1} in the checkpoint and {shape2} in the model instantiated"
+                    for key, shape1, shape2 in mismatched_keys
+                ]
+            )
+            logger.warning(
+                f"Some weights of {model.__class__.__name__} were not initialized from the model checkpoint at"
+                f" {pretrained_model_name_or_path} and are newly initialized because the shapes did not"
+                f" match:\n{mismatched_warning}\nYou should probably TRAIN this model on a down-stream task to be"
+                " able to use it for predictions and inference."
+            )
+
+        return model, missing_keys, unexpected_keys, mismatched_keys, error_msgs
+
+    @property
+    def device(self) -> device:
+        """
+        `torch.device`: The device on which the module is (assuming that all the module parameters are on the same
+        device).
+        """
+        return get_parameter_device(self)
+
+    @property
+    def dtype(self) -> torch.dtype:
+        """
+        `torch.dtype`: The dtype of the module (assuming that all the module parameters have the same dtype).
+        """
+        return get_parameter_dtype(self)
+
+    def num_parameters(self, only_trainable: bool = False, exclude_embeddings: bool = False) -> int:
+        """
+        Get number of (optionally, trainable or non-embeddings) parameters in the module.
+
+        Args:
+            only_trainable (`bool`, *optional*, defaults to `False`):
+                Whether or not to return only the number of trainable parameters
+
+            exclude_embeddings (`bool`, *optional*, defaults to `False`):
+                Whether or not to return only the number of non-embeddings parameters
+
+        Returns:
+            `int`: The number of parameters.
+        """
+
+        if exclude_embeddings:
+            embedding_param_names = [
+                f"{name}.weight"
+                for name, module_type in self.named_modules()
+                if isinstance(module_type, torch.nn.Embedding)
+            ]
+            non_embedding_parameters = [
+                parameter for name, parameter in self.named_parameters() if name not in embedding_param_names
+            ]
+            return sum(p.numel() for p in non_embedding_parameters if p.requires_grad or not only_trainable)
+        else:
+            return sum(p.numel() for p in self.parameters() if p.requires_grad or not only_trainable)
+
+
+def unwrap_model(model: torch.nn.Module) -> torch.nn.Module:
+    """
+    Recursively unwraps a model from potential containers (as used in distributed training).
+
+    Args:
+        model (`torch.nn.Module`): The model to unwrap.
+    """
+    # since there could be multiple levels of wrapping, unwrap recursively
+    if hasattr(model, "module"):
+        return unwrap_model(model.module)
+    else:
+        return model

diffusers/models/__init__.py

@@ -0,0 +1,17 @@
+# Copyright 2022 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .unet_2d import UNet2DModel
+from .unet_2d_condition import UNet2DConditionModel
+from .vae import AutoencoderKL, VQModel

diffusers/models/attention.py

@@ -0,0 +1,409 @@
+import math
+from collections import defaultdict
+from typing import Optional
+
+import torch
+import torch.nn.functional as F
+from torch import nn
+
+
+class AttentionBlock(nn.Module):
+    """
+    An attention block that allows spatial positions to attend to each other. Originally ported from here, but adapted
+    to the N-d case.
+    https://github.com/hojonathanho/diffusion/blob/1e0dceb3b3495bbe19116a5e1b3596cd0706c543/diffusion_tf/models/unet.py#L66.
+    Uses three q, k, v linear layers to compute attention.
+
+    Parameters:
+        channels (:obj:`int`): The number of channels in the input and output.
+        num_head_channels (:obj:`int`, *optional*):
+            The number of channels in each head. If None, then `num_heads` = 1.
+        num_groups (:obj:`int`, *optional*, defaults to 32): The number of groups to use for group norm.
+        rescale_output_factor (:obj:`float`, *optional*, defaults to 1.0): The factor to rescale the output by.
+        eps (:obj:`float`, *optional*, defaults to 1e-5): The epsilon value to use for group norm.
+    """
+
+    def __init__(
+        self,
+        channels: int,
+        num_head_channels: Optional[int] = None,
+        num_groups: int = 32,
+        rescale_output_factor: float = 1.0,
+        eps: float = 1e-5,
+    ):
+        super().__init__()
+        self.channels = channels
+
+        self.num_heads = channels // num_head_channels if num_head_channels is not None else 1
+        self.num_head_size = num_head_channels
+        self.group_norm = nn.GroupNorm(num_channels=channels, num_groups=num_groups, eps=eps, affine=True)
+
+        # define q,k,v as linear layers
+        self.query = nn.Linear(channels, channels)
+        self.key = nn.Linear(channels, channels)
+        self.value = nn.Linear(channels, channels)
+
+        self.rescale_output_factor = rescale_output_factor
+        self.proj_attn = nn.Linear(channels, channels, 1)
+
+    def transpose_for_scores(self, projection: torch.Tensor) -> torch.Tensor:
+        new_projection_shape = projection.size()[:-1] + (self.num_heads, -1)
+        # move heads to 2nd position (B, T, H * D) -> (B, T, H, D) -> (B, H, T, D)
+        new_projection = projection.view(new_projection_shape).permute(0, 2, 1, 3)
+        return new_projection
+
+    def forward(self, hidden_states):
+        residual = hidden_states
+        batch, channel, height, width = hidden_states.shape
+
+        # norm
+        hidden_states = self.group_norm(hidden_states)
+
+        hidden_states = hidden_states.view(batch, channel, height * width).transpose(1, 2)
+
+        # proj to q, k, v
+        query_proj = self.query(hidden_states)
+        key_proj = self.key(hidden_states)
+        value_proj = self.value(hidden_states)
+
+        # transpose
+        query_states = self.transpose_for_scores(query_proj)
+        key_states = self.transpose_for_scores(key_proj)
+        value_states = self.transpose_for_scores(value_proj)
+
+        # get scores
+        scale = 1 / math.sqrt(math.sqrt(self.channels / self.num_heads))
+
+        attention_scores = torch.matmul(query_states * scale, key_states.transpose(-1, -2) * scale)
+        attention_probs = torch.softmax(attention_scores.float(), dim=-1).type(attention_scores.dtype)
+
+        # compute attention output
+        hidden_states = torch.matmul(attention_probs, value_states)
+
+        hidden_states = hidden_states.permute(0, 2, 1, 3).contiguous()
+        new_hidden_states_shape = hidden_states.size()[:-2] + (self.channels,)
+        hidden_states = hidden_states.view(new_hidden_states_shape)
+
+        # compute next hidden_states
+        hidden_states = self.proj_attn(hidden_states)
+        hidden_states = hidden_states.transpose(-1, -2).reshape(batch, channel, height, width)
+
+        # res connect and rescale
+        hidden_states = (hidden_states + residual) / self.rescale_output_factor
+        return hidden_states
+
+
+class SpatialTransformer(nn.Module):
+    """
+    Transformer block for image-like data. First, project the input (aka embedding) and reshape to b, t, d. Then apply
+    standard transformer action. Finally, reshape to image.
+
+    Parameters:
+        in_channels (:obj:`int`): The number of channels in the input and output.
+        n_heads (:obj:`int`): The number of heads to use for multi-head attention.
+        d_head (:obj:`int`): The number of channels in each head.
+        depth (:obj:`int`, *optional*, defaults to 1): The number of layers of Transformer blocks to use.
+        dropout (:obj:`float`, *optional*, defaults to 0.1): The dropout probability to use.
+        context_dim (:obj:`int`, *optional*): The number of context dimensions to use.
+    """
+
+    def __init__(
+        self,
+        in_channels: int,
+        n_heads: int,
+        d_head: int,
+        depth: int = 1,
+        dropout: float = 0.0,
+        context_dim: Optional[int] = None,
+    ):
+        super().__init__()
+        self.n_heads = n_heads
+        self.d_head = d_head
+        self.in_channels = in_channels
+        inner_dim = n_heads * d_head
+        self.norm = torch.nn.GroupNorm(num_groups=32, num_channels=in_channels, eps=1e-6, affine=True)
+
+        self.proj_in = nn.Conv2d(in_channels, inner_dim, kernel_size=1, stride=1, padding=0)
+
+        self.transformer_blocks = nn.ModuleList(
+            [
+                BasicTransformerBlock(inner_dim, n_heads, d_head, dropout=dropout, context_dim=context_dim)
+                for d in range(depth)
+            ]
+        )
+
+        self.proj_out = nn.Conv2d(inner_dim, in_channels, kernel_size=1, stride=1, padding=0)
+
+    def _set_attention_slice(self, slice_size):
+        for block in self.transformer_blocks:
+            block._set_attention_slice(slice_size)
+
+    def forward(self, x, context=None):
+        # note: if no context is given, cross-attention defaults to self-attention
+        b, c, h, w = x.shape
+        x_in = x
+        x = self.norm(x)
+        x = self.proj_in(x)
+        x = x.permute(0, 2, 3, 1).reshape(b, h * w, c)
+        for block in self.transformer_blocks:
+            x = block(x, context=context)
+        x = x.reshape(b, h, w, c).permute(0, 3, 1, 2)
+        x = self.proj_out(x)
+        return x + x_in
+
+
+class BasicTransformerBlock(nn.Module):
+    r"""
+    A basic Transformer block.
+
+    Parameters:
+        dim (:obj:`int`): The number of channels in the input and output.
+        n_heads (:obj:`int`): The number of heads to use for multi-head attention.
+        d_head (:obj:`int`): The number of channels in each head.
+        dropout (:obj:`float`, *optional*, defaults to 0.0): The dropout probability to use.
+        context_dim (:obj:`int`, *optional*): The size of the context vector for cross attention.
+        gated_ff (:obj:`bool`, *optional*, defaults to :obj:`False`): Whether to use a gated feed-forward network.
+        checkpoint (:obj:`bool`, *optional*, defaults to :obj:`False`): Whether to use checkpointing.
+    """
+
+    def __init__(
+        self,
+        dim: int,
+        n_heads: int,
+        d_head: int,
+        dropout=0.0,
+        context_dim: Optional[int] = None,
+        gated_ff: bool = True,
+        checkpoint: bool = True,
+    ):
+        super().__init__()
+        self.attn1 = CrossAttention(
+            query_dim=dim, heads=n_heads, dim_head=d_head, dropout=dropout
+        )  # is a self-attention
+        self.ff = FeedForward(dim, dropout=dropout, glu=gated_ff)
+        self.attn2 = CrossAttention(
+            query_dim=dim, context_dim=context_dim, heads=n_heads, dim_head=d_head, dropout=dropout
+        )  # is self-attn if context is none
+        self.norm1 = nn.LayerNorm(dim)
+        self.norm2 = nn.LayerNorm(dim)
+        self.norm3 = nn.LayerNorm(dim)
+        self.checkpoint = checkpoint
+
+    def _set_attention_slice(self, slice_size):
+        self.attn1._slice_size = slice_size
+        self.attn2._slice_size = slice_size
+
+    def forward(self, x, context=None):
+        x = x.contiguous() if x.device.type == "mps" else x
+        x = self.attn1(self.norm1(x)) + x
+        x = self.attn2(self.norm2(x), context=context) + x
+        x = self.ff(self.norm3(x)) + x
+        return x
+
+
+heat_maps = defaultdict(list)
+all_heat_maps = []
+
+
+def clear_heat_maps():
+    global heat_maps, all_heat_maps
+    heat_maps = defaultdict(list)
+    all_heat_maps = []
+
+
+def next_heat_map():
+    global heat_maps, all_heat_maps
+    all_heat_maps.append(heat_maps)
+    heat_maps = defaultdict(list)
+
+
+def get_global_heat_map(last_n: int = None, idx: int = None, factors=None):
+    global heat_maps, all_heat_maps
+
+    if idx is not None:
+        heat_maps2 = [all_heat_maps[idx]]
+    else:
+        heat_maps2 = all_heat_maps[-last_n:] if last_n is not None else all_heat_maps
+
+    if factors is None:
+        factors = {1, 2, 4, 8, 16, 32}
+
+    all_merges = []
+
+    for heat_map_map in heat_maps2:
+        merge_list = []
+
+        for k, v in heat_map_map.items():
+            if k in factors:
+                merge_list.append(torch.stack(v, 0).mean(0))
+
+        all_merges.append(merge_list)
+
+    maps = torch.stack([torch.stack(x, 0) for x in all_merges], dim=0)
+    return maps.sum(0).cuda().sum(2).sum(0)
+
+
+class CrossAttention(nn.Module):
+    r"""
+    A cross attention layer.
+
+    Parameters:
+        query_dim (:obj:`int`): The number of channels in the query.
+        context_dim (:obj:`int`, *optional*):
+            The number of channels in the context. If not given, defaults to `query_dim`.
+        heads (:obj:`int`,  *optional*, defaults to 8): The number of heads to use for multi-head attention.
+        dim_head (:obj:`int`,  *optional*, defaults to 64): The number of channels in each head.
+        dropout (:obj:`float`, *optional*, defaults to 0.0): The dropout probability to use.
+    """
+
+    def __init__(
+        self, query_dim: int, context_dim: Optional[int] = None, heads: int = 8, dim_head: int = 64, dropout: int = 0.0
+    ):
+        super().__init__()
+        inner_dim = dim_head * heads
+        context_dim = context_dim if context_dim is not None else query_dim
+
+        self.scale = dim_head**-0.5
+        self.heads = heads
+        # for slice_size > 0 the attention score computation
+        # is split across the batch axis to save memory
+        # You can set slice_size with `set_attention_slice`
+        self._slice_size = None
+
+        self.to_q = nn.Linear(query_dim, inner_dim, bias=False)
+        self.to_k = nn.Linear(context_dim, inner_dim, bias=False)
+        self.to_v = nn.Linear(context_dim, inner_dim, bias=False)
+
+        self.to_out = nn.Sequential(nn.Linear(inner_dim, query_dim), nn.Dropout(dropout))
+
+    def reshape_heads_to_batch_dim(self, tensor):
+        batch_size, seq_len, dim = tensor.shape
+        head_size = self.heads
+        tensor = tensor.reshape(batch_size, seq_len, head_size, dim // head_size)
+        tensor = tensor.permute(0, 2, 1, 3).reshape(batch_size * head_size, seq_len, dim // head_size)
+        return tensor
+
+    def reshape_batch_dim_to_heads(self, tensor):
+        batch_size, seq_len, dim = tensor.shape
+        head_size = self.heads
+        tensor = tensor.reshape(batch_size // head_size, head_size, seq_len, dim)
+        tensor = tensor.permute(0, 2, 1, 3).reshape(batch_size // head_size, seq_len, dim * head_size)
+        return tensor
+
+    def forward(self, x, context=None, mask=None):
+        batch_size, sequence_length, dim = x.shape
+
+        use_context = context is not None
+
+        q = self.to_q(x)
+        context = context if context is not None else x
+        k = self.to_k(context)
+        v = self.to_v(context)
+
+        q = self.reshape_heads_to_batch_dim(q)
+        k = self.reshape_heads_to_batch_dim(k)
+        v = self.reshape_heads_to_batch_dim(v)
+
+        # TODO(PVP) - mask is currently never used. Remember to re-implement when used
+
+        # attention, what we cannot get enough of
+        hidden_states = self._attention(q, k, v, sequence_length, dim, use_context=use_context)
+
+        return self.to_out(hidden_states)
+
+    @torch.no_grad()
+    def _up_sample_attn(self, x, factor, method: str = 'bicubic'):
+        weight = torch.full((factor, factor), 1 / factor**2, device=x.device)
+        weight = weight.view(1, 1, factor, factor)
+
+        h = w = int(math.sqrt(x.size(1)))
+        maps = []
+        x = x.permute(2, 0, 1)
+
+        with torch.cuda.amp.autocast(dtype=torch.float32):
+            for map_ in x:
+                map_ = map_.unsqueeze(1).view(map_.size(0), 1, h, w)
+                if method == 'bicubic':
+                    map_ = F.interpolate(map_, size=(55, 55), mode="bicubic", align_corners=False)
+                    maps.append(map_.squeeze(1))
+                else:
+                    maps.append(F.conv_transpose2d(map_, weight, stride=factor).squeeze(1).cpu())
+
+        maps = torch.stack(maps, 0).cpu()
+        return maps
+
+    def _attention(self, query, key, value, sequence_length, dim, use_context: bool = True):
+        batch_size_attention = query.shape[0]
+        hidden_states = torch.zeros(
+            (batch_size_attention, sequence_length, dim // self.heads), device=query.device, dtype=query.dtype
+        )
+        slice_size = self._slice_size if self._slice_size is not None else hidden_states.shape[0]
+        for i in range(hidden_states.shape[0] // slice_size):
+            start_idx = i * slice_size
+            end_idx = (i + 1) * slice_size
+            attn_slice = (
+                torch.einsum("b i d, b j d -> b i j", query[start_idx:end_idx], key[start_idx:end_idx]) * self.scale
+            )
+            factor = int(math.sqrt(4096 // attn_slice.shape[1]))
+            attn_slice = attn_slice.softmax(-1)
+
+            if use_context:
+                if factor >= 1:
+                    factor //= 1
+                    maps = self._up_sample_attn(attn_slice, factor)
+                    global heat_maps
+                    heat_maps[factor].append(maps)
+                # print(attn_slice.size(), query.size(), key.size(), value.size())
+
+            attn_slice = torch.einsum("b i j, b j d -> b i d", attn_slice, value[start_idx:end_idx])
+
+            hidden_states[start_idx:end_idx] = attn_slice
+
+        # reshape hidden_states
+        hidden_states = self.reshape_batch_dim_to_heads(hidden_states)
+        return hidden_states
+
+
+class FeedForward(nn.Module):
+    r"""
+    A feed-forward layer.
+
+    Parameters:
+        dim (:obj:`int`): The number of channels in the input.
+        dim_out (:obj:`int`, *optional*): The number of channels in the output. If not given, defaults to `dim`.
+        mult (:obj:`int`, *optional*, defaults to 4): The multiplier to use for the hidden dimension.
+        glu (:obj:`bool`, *optional*, defaults to :obj:`False`): Whether to use GLU activation.
+        dropout (:obj:`float`, *optional*, defaults to 0.0): The dropout probability to use.
+    """
+
+    def __init__(
+        self, dim: int, dim_out: Optional[int] = None, mult: int = 4, glu: bool = False, dropout: float = 0.0
+    ):
+        super().__init__()
+        inner_dim = int(dim * mult)
+        dim_out = dim_out if dim_out is not None else dim
+        project_in = GEGLU(dim, inner_dim)
+
+        self.net = nn.Sequential(project_in, nn.Dropout(dropout), nn.Linear(inner_dim, dim_out))
+
+    def forward(self, x):
+        return self.net(x)
+
+
+# feedforward
+class GEGLU(nn.Module):
+    r"""
+    A variant of the gated linear unit activation function from https://arxiv.org/abs/2002.05202.
+
+    Parameters:
+        dim_in (:obj:`int`): The number of channels in the input.
+        dim_out (:obj:`int`): The number of channels in the output.
+    """
+
+    def __init__(self, dim_in: int, dim_out: int):
+        super().__init__()
+        self.proj = nn.Linear(dim_in, dim_out * 2)
+
+    def forward(self, x):
+        x, gate = self.proj(x).chunk(2, dim=-1)
+        return x * F.gelu(gate)

diffusers/models/embeddings.py

@@ -0,0 +1,115 @@
+# Copyright 2022 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import math
+
+import numpy as np
+import torch
+from torch import nn
+
+
+def get_timestep_embedding(
+    timesteps: torch.Tensor,
+    embedding_dim: int,
+    flip_sin_to_cos: bool = False,
+    downscale_freq_shift: float = 1,
+    scale: float = 1,
+    max_period: int = 10000,
+):
+    """
+    This matches the implementation in Denoising Diffusion Probabilistic Models: Create sinusoidal timestep embeddings.
+
+    :param timesteps: a 1-D Tensor of N indices, one per batch element.
+                      These may be fractional.
+    :param embedding_dim: the dimension of the output. :param max_period: controls the minimum frequency of the
+    embeddings. :return: an [N x dim] Tensor of positional embeddings.
+    """
+    assert len(timesteps.shape) == 1, "Timesteps should be a 1d-array"
+
+    half_dim = embedding_dim // 2
+    exponent = -math.log(max_period) * torch.arange(start=0, end=half_dim, dtype=torch.float32)
+    exponent = exponent / (half_dim - downscale_freq_shift)
+
+    emb = torch.exp(exponent).to(device=timesteps.device)
+    emb = timesteps[:, None].float() * emb[None, :]
+
+    # scale embeddings
+    emb = scale * emb
+
+    # concat sine and cosine embeddings
+    emb = torch.cat([torch.sin(emb), torch.cos(emb)], dim=-1)
+
+    # flip sine and cosine embeddings
+    if flip_sin_to_cos:
+        emb = torch.cat([emb[:, half_dim:], emb[:, :half_dim]], dim=-1)
+
+    # zero pad
+    if embedding_dim % 2 == 1:
+        emb = torch.nn.functional.pad(emb, (0, 1, 0, 0))
+    return emb
+
+
+class TimestepEmbedding(nn.Module):
+    def __init__(self, channel: int, time_embed_dim: int, act_fn: str = "silu"):
+        super().__init__()
+
+        self.linear_1 = nn.Linear(channel, time_embed_dim)
+        self.act = None
+        if act_fn == "silu":
+            self.act = nn.SiLU()
+        self.linear_2 = nn.Linear(time_embed_dim, time_embed_dim)
+
+    def forward(self, sample):
+        sample = self.linear_1(sample)
+
+        if self.act is not None:
+            sample = self.act(sample)
+
+        sample = self.linear_2(sample)
+        return sample
+
+
+class Timesteps(nn.Module):
+    def __init__(self, num_channels: int, flip_sin_to_cos: bool, downscale_freq_shift: float):
+        super().__init__()
+        self.num_channels = num_channels
+        self.flip_sin_to_cos = flip_sin_to_cos
+        self.downscale_freq_shift = downscale_freq_shift
+
+    def forward(self, timesteps):
+        t_emb = get_timestep_embedding(
+            timesteps,
+            self.num_channels,
+            flip_sin_to_cos=self.flip_sin_to_cos,
+            downscale_freq_shift=self.downscale_freq_shift,
+        )
+        return t_emb
+
+
+class GaussianFourierProjection(nn.Module):
+    """Gaussian Fourier embeddings for noise levels."""
+
+    def __init__(self, embedding_size: int = 256, scale: float = 1.0):
+        super().__init__()
+        self.weight = nn.Parameter(torch.randn(embedding_size) * scale, requires_grad=False)
+
+        # to delete later
+        self.W = nn.Parameter(torch.randn(embedding_size) * scale, requires_grad=False)
+
+        self.weight = self.W
+
+    def forward(self, x):
+        x = torch.log(x)
+        x_proj = x[:, None] * self.weight[None, :] * 2 * np.pi
+        out = torch.cat([torch.sin(x_proj), torch.cos(x_proj)], dim=-1)
+        return out

diffusers/models/resnet.py

@@ -0,0 +1,483 @@
+from functools import partial
+
+import numpy as np
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+
+class Upsample2D(nn.Module):
+    """
+    An upsampling layer with an optional convolution.
+
+    :param channels: channels in the inputs and outputs. :param use_conv: a bool determining if a convolution is
+    applied. :param dims: determines if the signal is 1D, 2D, or 3D. If 3D, then
+                 upsampling occurs in the inner-two dimensions.
+    """
+
+    def __init__(self, channels, use_conv=False, use_conv_transpose=False, out_channels=None, name="conv"):
+        super().__init__()
+        self.channels = channels
+        self.out_channels = out_channels or channels
+        self.use_conv = use_conv
+        self.use_conv_transpose = use_conv_transpose
+        self.name = name
+
+        conv = None
+        if use_conv_transpose:
+            conv = nn.ConvTranspose2d(channels, self.out_channels, 4, 2, 1)
+        elif use_conv:
+            conv = nn.Conv2d(self.channels, self.out_channels, 3, padding=1)
+
+        # TODO(Suraj, Patrick) - clean up after weight dicts are correctly renamed
+        if name == "conv":
+            self.conv = conv
+        else:
+            self.Conv2d_0 = conv
+
+    def forward(self, x):
+        assert x.shape[1] == self.channels
+        if self.use_conv_transpose:
+            return self.conv(x)
+
+        x = F.interpolate(x, scale_factor=2.0, mode="nearest")
+
+        # TODO(Suraj, Patrick) - clean up after weight dicts are correctly renamed
+        if self.use_conv:
+            if self.name == "conv":
+                x = self.conv(x)
+            else:
+                x = self.Conv2d_0(x)
+
+        return x
+
+
+class Downsample2D(nn.Module):
+    """
+    A downsampling layer with an optional convolution.
+
+    :param channels: channels in the inputs and outputs. :param use_conv: a bool determining if a convolution is
+    applied. :param dims: determines if the signal is 1D, 2D, or 3D. If 3D, then
+                 downsampling occurs in the inner-two dimensions.
+    """
+
+    def __init__(self, channels, use_conv=False, out_channels=None, padding=1, name="conv"):
+        super().__init__()
+        self.channels = channels
+        self.out_channels = out_channels or channels
+        self.use_conv = use_conv
+        self.padding = padding
+        stride = 2
+        self.name = name
+
+        if use_conv:
+            conv = nn.Conv2d(self.channels, self.out_channels, 3, stride=stride, padding=padding)
+        else:
+            assert self.channels == self.out_channels
+            conv = nn.AvgPool2d(kernel_size=stride, stride=stride)
+
+        # TODO(Suraj, Patrick) - clean up after weight dicts are correctly renamed
+        if name == "conv":
+            self.Conv2d_0 = conv
+            self.conv = conv
+        elif name == "Conv2d_0":
+            self.conv = conv
+        else:
+            self.conv = conv
+
+    def forward(self, x):
+        assert x.shape[1] == self.channels
+        if self.use_conv and self.padding == 0:
+            pad = (0, 1, 0, 1)
+            x = F.pad(x, pad, mode="constant", value=0)
+
+        assert x.shape[1] == self.channels
+        x = self.conv(x)
+
+        return x
+
+
+class FirUpsample2D(nn.Module):
+    def __init__(self, channels=None, out_channels=None, use_conv=False, fir_kernel=(1, 3, 3, 1)):
+        super().__init__()
+        out_channels = out_channels if out_channels else channels
+        if use_conv:
+            self.Conv2d_0 = nn.Conv2d(channels, out_channels, kernel_size=3, stride=1, padding=1)
+        self.use_conv = use_conv
+        self.fir_kernel = fir_kernel
+        self.out_channels = out_channels
+
+    def _upsample_2d(self, x, weight=None, kernel=None, factor=2, gain=1):
+        """Fused `upsample_2d()` followed by `Conv2d()`.
+
+        Args:
+        Padding is performed only once at the beginning, not between the operations. The fused op is considerably more
+        efficient than performing the same calculation using standard TensorFlow ops. It supports gradients of arbitrary:
+        order.
+        x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W,
+            C]`.
+        weight: Weight tensor of the shape `[filterH, filterW, inChannels,
+            outChannels]`. Grouped convolution can be performed by `inChannels = x.shape[0] // numGroups`.
+        kernel: FIR filter of the shape `[firH, firW]` or `[firN]`
+            (separable). The default is `[1] * factor`, which corresponds to nearest-neighbor upsampling.
+        factor: Integer upsampling factor (default: 2). gain: Scaling factor for signal magnitude (default: 1.0).
+
+        Returns:
+        Tensor of the shape `[N, C, H * factor, W * factor]` or `[N, H * factor, W * factor, C]`, and same datatype as
+        `x`.
+        """
+
+        assert isinstance(factor, int) and factor >= 1
+
+        # Setup filter kernel.
+        if kernel is None:
+            kernel = [1] * factor
+
+        # setup kernel
+        kernel = np.asarray(kernel, dtype=np.float32)
+        if kernel.ndim == 1:
+            kernel = np.outer(kernel, kernel)
+        kernel /= np.sum(kernel)
+
+        kernel = kernel * (gain * (factor**2))
+
+        if self.use_conv:
+            convH = weight.shape[2]
+            convW = weight.shape[3]
+            inC = weight.shape[1]
+
+            p = (kernel.shape[0] - factor) - (convW - 1)
+
+            stride = (factor, factor)
+            # Determine data dimensions.
+            stride = [1, 1, factor, factor]
+            output_shape = ((x.shape[2] - 1) * factor + convH, (x.shape[3] - 1) * factor + convW)
+            output_padding = (
+                output_shape[0] - (x.shape[2] - 1) * stride[0] - convH,
+                output_shape[1] - (x.shape[3] - 1) * stride[1] - convW,
+            )
+            assert output_padding[0] >= 0 and output_padding[1] >= 0
+            inC = weight.shape[1]
+            num_groups = x.shape[1] // inC
+
+            # Transpose weights.
+            weight = torch.reshape(weight, (num_groups, -1, inC, convH, convW))
+            weight = weight[..., ::-1, ::-1].permute(0, 2, 1, 3, 4)
+            weight = torch.reshape(weight, (num_groups * inC, -1, convH, convW))
+
+            x = F.conv_transpose2d(x, weight, stride=stride, output_padding=output_padding, padding=0)
+
+            x = upfirdn2d_native(x, torch.tensor(kernel, device=x.device), pad=((p + 1) // 2 + factor - 1, p // 2 + 1))
+        else:
+            p = kernel.shape[0] - factor
+            x = upfirdn2d_native(
+                x, torch.tensor(kernel, device=x.device), up=factor, pad=((p + 1) // 2 + factor - 1, p // 2)
+            )
+
+        return x
+
+    def forward(self, x):
+        if self.use_conv:
+            height = self._upsample_2d(x, self.Conv2d_0.weight, kernel=self.fir_kernel)
+            height = height + self.Conv2d_0.bias.reshape(1, -1, 1, 1)
+        else:
+            height = self._upsample_2d(x, kernel=self.fir_kernel, factor=2)
+
+        return height
+
+
+class FirDownsample2D(nn.Module):
+    def __init__(self, channels=None, out_channels=None, use_conv=False, fir_kernel=(1, 3, 3, 1)):
+        super().__init__()
+        out_channels = out_channels if out_channels else channels
+        if use_conv:
+            self.Conv2d_0 = nn.Conv2d(channels, out_channels, kernel_size=3, stride=1, padding=1)
+        self.fir_kernel = fir_kernel
+        self.use_conv = use_conv
+        self.out_channels = out_channels
+
+    def _downsample_2d(self, x, weight=None, kernel=None, factor=2, gain=1):
+        """Fused `Conv2d()` followed by `downsample_2d()`.
+
+        Args:
+        Padding is performed only once at the beginning, not between the operations. The fused op is considerably more
+        efficient than performing the same calculation using standard TensorFlow ops. It supports gradients of arbitrary:
+        order.
+            x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W, C]`. w: Weight tensor of the shape `[filterH,
+            filterW, inChannels, outChannels]`. Grouped convolution can be performed by `inChannels = x.shape[0] //
+            numGroups`. k: FIR filter of the shape `[firH, firW]` or `[firN]` (separable). The default is `[1] *
+            factor`, which corresponds to average pooling. factor: Integer downsampling factor (default: 2). gain:
+            Scaling factor for signal magnitude (default: 1.0).
+
+        Returns:
+            Tensor of the shape `[N, C, H // factor, W // factor]` or `[N, H // factor, W // factor, C]`, and same
+            datatype as `x`.
+        """
+
+        assert isinstance(factor, int) and factor >= 1
+        if kernel is None:
+            kernel = [1] * factor
+
+        # setup kernel
+        kernel = np.asarray(kernel, dtype=np.float32)
+        if kernel.ndim == 1:
+            kernel = np.outer(kernel, kernel)
+        kernel /= np.sum(kernel)
+
+        kernel = kernel * gain
+
+        if self.use_conv:
+            _, _, convH, convW = weight.shape
+            p = (kernel.shape[0] - factor) + (convW - 1)
+            s = [factor, factor]
+            x = upfirdn2d_native(x, torch.tensor(kernel, device=x.device), pad=((p + 1) // 2, p // 2))
+            x = F.conv2d(x, weight, stride=s, padding=0)
+        else:
+            p = kernel.shape[0] - factor
+            x = upfirdn2d_native(x, torch.tensor(kernel, device=x.device), down=factor, pad=((p + 1) // 2, p // 2))
+
+        return x
+
+    def forward(self, x):
+        if self.use_conv:
+            x = self._downsample_2d(x, weight=self.Conv2d_0.weight, kernel=self.fir_kernel)
+            x = x + self.Conv2d_0.bias.reshape(1, -1, 1, 1)
+        else:
+            x = self._downsample_2d(x, kernel=self.fir_kernel, factor=2)
+
+        return x
+
+
+class ResnetBlock2D(nn.Module):
+    def __init__(
+        self,
+        *,
+        in_channels,
+        out_channels=None,
+        conv_shortcut=False,
+        dropout=0.0,
+        temb_channels=512,
+        groups=32,
+        groups_out=None,
+        pre_norm=True,
+        eps=1e-6,
+        non_linearity="swish",
+        time_embedding_norm="default",
+        kernel=None,
+        output_scale_factor=1.0,
+        use_nin_shortcut=None,
+        up=False,
+        down=False,
+    ):
+        super().__init__()
+        self.pre_norm = pre_norm
+        self.pre_norm = True
+        self.in_channels = in_channels
+        out_channels = in_channels if out_channels is None else out_channels
+        self.out_channels = out_channels
+        self.use_conv_shortcut = conv_shortcut
+        self.time_embedding_norm = time_embedding_norm
+        self.up = up
+        self.down = down
+        self.output_scale_factor = output_scale_factor
+
+        if groups_out is None:
+            groups_out = groups
+
+        self.norm1 = torch.nn.GroupNorm(num_groups=groups, num_channels=in_channels, eps=eps, affine=True)
+
+        self.conv1 = torch.nn.Conv2d(in_channels, out_channels, kernel_size=3, stride=1, padding=1)
+
+        if temb_channels is not None:
+            self.time_emb_proj = torch.nn.Linear(temb_channels, out_channels)
+        else:
+            self.time_emb_proj = None
+
+        self.norm2 = torch.nn.GroupNorm(num_groups=groups_out, num_channels=out_channels, eps=eps, affine=True)
+        self.dropout = torch.nn.Dropout(dropout)
+        self.conv2 = torch.nn.Conv2d(out_channels, out_channels, kernel_size=3, stride=1, padding=1)
+
+        if non_linearity == "swish":
+            self.nonlinearity = lambda x: F.silu(x)
+        elif non_linearity == "mish":
+            self.nonlinearity = Mish()
+        elif non_linearity == "silu":
+            self.nonlinearity = nn.SiLU()
+
+        self.upsample = self.downsample = None
+        if self.up:
+            if kernel == "fir":
+                fir_kernel = (1, 3, 3, 1)
+                self.upsample = lambda x: upsample_2d(x, kernel=fir_kernel)
+            elif kernel == "sde_vp":
+                self.upsample = partial(F.interpolate, scale_factor=2.0, mode="nearest")
+            else:
+                self.upsample = Upsample2D(in_channels, use_conv=False)
+        elif self.down:
+            if kernel == "fir":
+                fir_kernel = (1, 3, 3, 1)
+                self.downsample = lambda x: downsample_2d(x, kernel=fir_kernel)
+            elif kernel == "sde_vp":
+                self.downsample = partial(F.avg_pool2d, kernel_size=2, stride=2)
+            else:
+                self.downsample = Downsample2D(in_channels, use_conv=False, padding=1, name="op")
+
+        self.use_nin_shortcut = self.in_channels != self.out_channels if use_nin_shortcut is None else use_nin_shortcut
+
+        self.conv_shortcut = None
+        if self.use_nin_shortcut:
+            self.conv_shortcut = torch.nn.Conv2d(in_channels, out_channels, kernel_size=1, stride=1, padding=0)
+
+    def forward(self, x, temb):
+        hidden_states = x
+
+        # make sure hidden states is in float32
+        # when running in half-precision
+        hidden_states = self.norm1(hidden_states.float()).type(hidden_states.dtype)
+        hidden_states = self.nonlinearity(hidden_states)
+
+        if self.upsample is not None:
+            x = self.upsample(x)
+            hidden_states = self.upsample(hidden_states)
+        elif self.downsample is not None:
+            x = self.downsample(x)
+            hidden_states = self.downsample(hidden_states)
+
+        hidden_states = self.conv1(hidden_states)
+
+        if temb is not None:
+            temb = self.time_emb_proj(self.nonlinearity(temb))[:, :, None, None]
+            hidden_states = hidden_states + temb
+
+        # make sure hidden states is in float32
+        # when running in half-precision
+        hidden_states = self.norm2(hidden_states.float()).type(hidden_states.dtype)
+        hidden_states = self.nonlinearity(hidden_states)
+
+        hidden_states = self.dropout(hidden_states)
+        hidden_states = self.conv2(hidden_states)
+
+        if self.conv_shortcut is not None:
+            x = self.conv_shortcut(x)
+
+        out = (x + hidden_states) / self.output_scale_factor
+
+        return out
+
+
+class Mish(torch.nn.Module):
+    def forward(self, x):
+        return x * torch.tanh(torch.nn.functional.softplus(x))
+
+
+def upsample_2d(x, kernel=None, factor=2, gain=1):
+    r"""Upsample2D a batch of 2D images with the given filter.
+
+    Args:
+    Accepts a batch of 2D images of the shape `[N, C, H, W]` or `[N, H, W, C]` and upsamples each image with the given
+    filter. The filter is normalized so that if the input pixels are constant, they will be scaled by the specified
+    `gain`. Pixels outside the image are assumed to be zero, and the filter is padded with zeros so that its shape is a:
+    multiple of the upsampling factor.
+        x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W,
+          C]`.
+        k: FIR filter of the shape `[firH, firW]` or `[firN]`
+          (separable). The default is `[1] * factor`, which corresponds to nearest-neighbor upsampling.
+        factor: Integer upsampling factor (default: 2). gain: Scaling factor for signal magnitude (default: 1.0).
+
+    Returns:
+        Tensor of the shape `[N, C, H * factor, W * factor]`
+    """
+    assert isinstance(factor, int) and factor >= 1
+    if kernel is None:
+        kernel = [1] * factor
+
+    kernel = np.asarray(kernel, dtype=np.float32)
+    if kernel.ndim == 1:
+        kernel = np.outer(kernel, kernel)
+    kernel /= np.sum(kernel)
+
+    kernel = kernel * (gain * (factor**2))
+    p = kernel.shape[0] - factor
+    return upfirdn2d_native(
+        x, torch.tensor(kernel, device=x.device), up=factor, pad=((p + 1) // 2 + factor - 1, p // 2)
+    )
+
+
+def downsample_2d(x, kernel=None, factor=2, gain=1):
+    r"""Downsample2D a batch of 2D images with the given filter.
+
+    Args:
+    Accepts a batch of 2D images of the shape `[N, C, H, W]` or `[N, H, W, C]` and downsamples each image with the
+    given filter. The filter is normalized so that if the input pixels are constant, they will be scaled by the
+    specified `gain`. Pixels outside the image are assumed to be zero, and the filter is padded with zeros so that its
+    shape is a multiple of the downsampling factor.
+        x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W,
+          C]`.
+        kernel: FIR filter of the shape `[firH, firW]` or `[firN]`
+          (separable). The default is `[1] * factor`, which corresponds to average pooling.
+        factor: Integer downsampling factor (default: 2). gain: Scaling factor for signal magnitude (default: 1.0).
+
+    Returns:
+        Tensor of the shape `[N, C, H // factor, W // factor]`
+    """
+
+    assert isinstance(factor, int) and factor >= 1
+    if kernel is None:
+        kernel = [1] * factor
+
+    kernel = np.asarray(kernel, dtype=np.float32)
+    if kernel.ndim == 1:
+        kernel = np.outer(kernel, kernel)
+    kernel /= np.sum(kernel)
+
+    kernel = kernel * gain
+    p = kernel.shape[0] - factor
+    return upfirdn2d_native(x, torch.tensor(kernel, device=x.device), down=factor, pad=((p + 1) // 2, p // 2))
+
+
+def upfirdn2d_native(input, kernel, up=1, down=1, pad=(0, 0)):
+    up_x = up_y = up
+    down_x = down_y = down
+    pad_x0 = pad_y0 = pad[0]
+    pad_x1 = pad_y1 = pad[1]
+
+    _, channel, in_h, in_w = input.shape
+    input = input.reshape(-1, in_h, in_w, 1)
+
+    _, in_h, in_w, minor = input.shape
+    kernel_h, kernel_w = kernel.shape
+
+    out = input.view(-1, in_h, 1, in_w, 1, minor)
+
+    # Temporary workaround for mps specific issue: https://github.com/pytorch/pytorch/issues/84535
+    if input.device.type == "mps":
+        out = out.to("cpu")
+    out = F.pad(out, [0, 0, 0, up_x - 1, 0, 0, 0, up_y - 1])
+    out = out.view(-1, in_h * up_y, in_w * up_x, minor)
+
+    out = F.pad(out, [0, 0, max(pad_x0, 0), max(pad_x1, 0), max(pad_y0, 0), max(pad_y1, 0)])
+    out = out.to(input.device)  # Move back to mps if necessary
+    out = out[
+        :,
+        max(-pad_y0, 0) : out.shape[1] - max(-pad_y1, 0),
+        max(-pad_x0, 0) : out.shape[2] - max(-pad_x1, 0),
+        :,
+    ]
+
+    out = out.permute(0, 3, 1, 2)
+    out = out.reshape([-1, 1, in_h * up_y + pad_y0 + pad_y1, in_w * up_x + pad_x0 + pad_x1])
+    w = torch.flip(kernel, [0, 1]).view(1, 1, kernel_h, kernel_w)
+    out = F.conv2d(out, w)
+    out = out.reshape(
+        -1,
+        minor,
+        in_h * up_y + pad_y0 + pad_y1 - kernel_h + 1,
+        in_w * up_x + pad_x0 + pad_x1 - kernel_w + 1,
+    )
+    out = out.permute(0, 2, 3, 1)
+    out = out[:, ::down_y, ::down_x, :]
+
+    out_h = (in_h * up_y + pad_y0 + pad_y1 - kernel_h) // down_y + 1
+    out_w = (in_w * up_x + pad_x0 + pad_x1 - kernel_w) // down_x + 1
+
+    return out.view(-1, channel, out_h, out_w)

diffusers/models/unet_2d.py

@@ -0,0 +1,246 @@
+from dataclasses import dataclass
+from typing import Optional, Tuple, Union
+
+import torch
+import torch.nn as nn
+
+from ..configuration_utils import ConfigMixin, register_to_config
+from ..modeling_utils import ModelMixin
+from ..utils import BaseOutput
+from .embeddings import GaussianFourierProjection, TimestepEmbedding, Timesteps
+from .unet_blocks import UNetMidBlock2D, get_down_block, get_up_block
+
+
+@dataclass
+class UNet2DOutput(BaseOutput):
+    """
+    Args:
+        sample (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
+            Hidden states output. Output of last layer of model.
+    """
+
+    sample: torch.FloatTensor
+
+
+class UNet2DModel(ModelMixin, ConfigMixin):
+    r"""
+    UNet2DModel is a 2D UNet model that takes in a noisy sample and a timestep and returns sample shaped output.
+
+    This model inherits from [`ModelMixin`]. Check the superclass documentation for the generic methods the library
+    implements for all the model (such as downloading or saving, etc.)
+
+    Parameters:
+        sample_size (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`, *optional*):
+            Input sample size.
+        in_channels (`int`, *optional*, defaults to 3): Number of channels in the input image.
+        out_channels (`int`, *optional*, defaults to 3): Number of channels in the output.
+        center_input_sample (`bool`, *optional*, defaults to `False`): Whether to center the input sample.
+        time_embedding_type (`str`, *optional*, defaults to `"positional"`): Type of time embedding to use.
+        freq_shift (`int`, *optional*, defaults to 0): Frequency shift for fourier time embedding.
+        flip_sin_to_cos (`bool`, *optional*, defaults to :
+            obj:`False`): Whether to flip sin to cos for fourier time embedding.
+        down_block_types (`Tuple[str]`, *optional*, defaults to :
+            obj:`("DownBlock2D", "AttnDownBlock2D", "AttnDownBlock2D", "AttnDownBlock2D")`): Tuple of downsample block
+            types.
+        up_block_types (`Tuple[str]`, *optional*, defaults to :
+            obj:`("AttnUpBlock2D", "AttnUpBlock2D", "AttnUpBlock2D", "UpBlock2D")`): Tuple of upsample block types.
+        block_out_channels (`Tuple[int]`, *optional*, defaults to :
+            obj:`(224, 448, 672, 896)`): Tuple of block output channels.
+        layers_per_block (`int`, *optional*, defaults to `2`): The number of layers per block.
+        mid_block_scale_factor (`float`, *optional*, defaults to `1`): The scale factor for the mid block.
+        downsample_padding (`int`, *optional*, defaults to `1`): The padding for the downsample convolution.
+        act_fn (`str`, *optional*, defaults to `"silu"`): The activation function to use.
+        attention_head_dim (`int`, *optional*, defaults to `8`): The attention head dimension.
+        norm_num_groups (`int`, *optional*, defaults to `32`): The number of groups for the normalization.
+        norm_eps (`float`, *optional*, defaults to `1e-5`): The epsilon for the normalization.
+    """
+
+    @register_to_config
+    def __init__(
+        self,
+        sample_size: Optional[int] = None,
+        in_channels: int = 3,
+        out_channels: int = 3,
+        center_input_sample: bool = False,
+        time_embedding_type: str = "positional",
+        freq_shift: int = 0,
+        flip_sin_to_cos: bool = True,
+        down_block_types: Tuple[str] = ("DownBlock2D", "AttnDownBlock2D", "AttnDownBlock2D", "AttnDownBlock2D"),
+        up_block_types: Tuple[str] = ("AttnUpBlock2D", "AttnUpBlock2D", "AttnUpBlock2D", "UpBlock2D"),
+        block_out_channels: Tuple[int] = (224, 448, 672, 896),
+        layers_per_block: int = 2,
+        mid_block_scale_factor: float = 1,
+        downsample_padding: int = 1,
+        act_fn: str = "silu",
+        attention_head_dim: int = 8,
+        norm_num_groups: int = 32,
+        norm_eps: float = 1e-5,
+    ):
+        super().__init__()
+
+        self.sample_size = sample_size
+        time_embed_dim = block_out_channels[0] * 4
+
+        # input
+        self.conv_in = nn.Conv2d(in_channels, block_out_channels[0], kernel_size=3, padding=(1, 1))
+
+        # time
+        if time_embedding_type == "fourier":
+            self.time_proj = GaussianFourierProjection(embedding_size=block_out_channels[0], scale=16)
+            timestep_input_dim = 2 * block_out_channels[0]
+        elif time_embedding_type == "positional":
+            self.time_proj = Timesteps(block_out_channels[0], flip_sin_to_cos, freq_shift)
+            timestep_input_dim = block_out_channels[0]
+
+        self.time_embedding = TimestepEmbedding(timestep_input_dim, time_embed_dim)
+
+        self.down_blocks = nn.ModuleList([])
+        self.mid_block = None
+        self.up_blocks = nn.ModuleList([])
+
+        # down
+        output_channel = block_out_channels[0]
+        for i, down_block_type in enumerate(down_block_types):
+            input_channel = output_channel
+            output_channel = block_out_channels[i]
+            is_final_block = i == len(block_out_channels) - 1
+
+            down_block = get_down_block(
+                down_block_type,
+                num_layers=layers_per_block,
+                in_channels=input_channel,
+                out_channels=output_channel,
+                temb_channels=time_embed_dim,
+                add_downsample=not is_final_block,
+                resnet_eps=norm_eps,
+                resnet_act_fn=act_fn,
+                attn_num_head_channels=attention_head_dim,
+                downsample_padding=downsample_padding,
+            )
+            self.down_blocks.append(down_block)
+
+        # mid
+        self.mid_block = UNetMidBlock2D(
+            in_channels=block_out_channels[-1],
+            temb_channels=time_embed_dim,
+            resnet_eps=norm_eps,
+            resnet_act_fn=act_fn,
+            output_scale_factor=mid_block_scale_factor,
+            resnet_time_scale_shift="default",
+            attn_num_head_channels=attention_head_dim,
+            resnet_groups=norm_num_groups,
+        )
+
+        # up
+        reversed_block_out_channels = list(reversed(block_out_channels))
+        output_channel = reversed_block_out_channels[0]
+        for i, up_block_type in enumerate(up_block_types):
+            prev_output_channel = output_channel
+            output_channel = reversed_block_out_channels[i]
+            input_channel = reversed_block_out_channels[min(i + 1, len(block_out_channels) - 1)]
+
+            is_final_block = i == len(block_out_channels) - 1
+
+            up_block = get_up_block(
+                up_block_type,
+                num_layers=layers_per_block + 1,
+                in_channels=input_channel,
+                out_channels=output_channel,
+                prev_output_channel=prev_output_channel,
+                temb_channels=time_embed_dim,
+                add_upsample=not is_final_block,
+                resnet_eps=norm_eps,
+                resnet_act_fn=act_fn,
+                attn_num_head_channels=attention_head_dim,
+            )
+            self.up_blocks.append(up_block)
+            prev_output_channel = output_channel
+
+        # out
+        num_groups_out = norm_num_groups if norm_num_groups is not None else min(block_out_channels[0] // 4, 32)
+        self.conv_norm_out = nn.GroupNorm(num_channels=block_out_channels[0], num_groups=num_groups_out, eps=norm_eps)
+        self.conv_act = nn.SiLU()
+        self.conv_out = nn.Conv2d(block_out_channels[0], out_channels, 3, padding=1)
+
+    def forward(
+        self,
+        sample: torch.FloatTensor,
+        timestep: Union[torch.Tensor, float, int],
+        return_dict: bool = True,
+    ) -> Union[UNet2DOutput, Tuple]:
+        """r
+        Args:
+            sample (`torch.FloatTensor`): (batch, channel, height, width) noisy inputs tensor
+            timestep (`torch.FloatTensor` or `float` or `int): (batch) timesteps
+            return_dict (`bool`, *optional*, defaults to `True`):
+                Whether or not to return a [`~models.unet_2d.UNet2DOutput`] instead of a plain tuple.
+
+        Returns:
+            [`~models.unet_2d.UNet2DOutput`] or `tuple`: [`~models.unet_2d.UNet2DOutput`] if `return_dict` is True,
+            otherwise a `tuple`. When returning a tuple, the first element is the sample tensor.
+        """
+        # 0. center input if necessary
+        if self.config.center_input_sample:
+            sample = 2 * sample - 1.0
+
+        # 1. time
+        timesteps = timestep
+        if not torch.is_tensor(timesteps):
+            timesteps = torch.tensor([timesteps], dtype=torch.long, device=sample.device)
+        elif torch.is_tensor(timesteps) and len(timesteps.shape) == 0:
+            timesteps = timesteps[None].to(sample.device)
+
+        # broadcast to batch dimension in a way that's compatible with ONNX/Core ML
+        timesteps = timesteps * torch.ones(sample.shape[0], dtype=timesteps.dtype, device=timesteps.device)
+
+        t_emb = self.time_proj(timesteps)
+        emb = self.time_embedding(t_emb)
+
+        # 2. pre-process
+        skip_sample = sample
+        sample = self.conv_in(sample)
+
+        # 3. down
+        down_block_res_samples = (sample,)
+        for downsample_block in self.down_blocks:
+            if hasattr(downsample_block, "skip_conv"):
+                sample, res_samples, skip_sample = downsample_block(
+                    hidden_states=sample, temb=emb, skip_sample=skip_sample
+                )
+            else:
+                sample, res_samples = downsample_block(hidden_states=sample, temb=emb)
+
+            down_block_res_samples += res_samples
+
+        # 4. mid
+        sample = self.mid_block(sample, emb)
+
+        # 5. up
+        skip_sample = None
+        for upsample_block in self.up_blocks:
+            res_samples = down_block_res_samples[-len(upsample_block.resnets) :]
+            down_block_res_samples = down_block_res_samples[: -len(upsample_block.resnets)]
+
+            if hasattr(upsample_block, "skip_conv"):
+                sample, skip_sample = upsample_block(sample, res_samples, emb, skip_sample)
+            else:
+                sample = upsample_block(sample, res_samples, emb)
+
+        # 6. post-process
+        # make sure hidden states is in float32
+        # when running in half-precision
+        sample = self.conv_norm_out(sample.float()).type(sample.dtype)
+        sample = self.conv_act(sample)
+        sample = self.conv_out(sample)
+
+        if skip_sample is not None:
+            sample += skip_sample
+
+        if self.config.time_embedding_type == "fourier":
+            timesteps = timesteps.reshape((sample.shape[0], *([1] * len(sample.shape[1:]))))
+            sample = sample / timesteps
+
+        if not return_dict:
+            return (sample,)
+
+        return UNet2DOutput(sample=sample)

diffusers/models/unet_2d_condition.py

@@ -0,0 +1,272 @@
+from dataclasses import dataclass
+from typing import Optional, Tuple, Union
+
+import torch
+import torch.nn as nn
+
+from ..configuration_utils import ConfigMixin, register_to_config
+from ..modeling_utils import ModelMixin
+from ..utils import BaseOutput
+from .embeddings import TimestepEmbedding, Timesteps
+from .unet_blocks import UNetMidBlock2DCrossAttn, get_down_block, get_up_block
+
+
+@dataclass
+class UNet2DConditionOutput(BaseOutput):
+    """
+    Args:
+        sample (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
+            Hidden states conditioned on `encoder_hidden_states` input. Output of last layer of model.
+    """
+
+    sample: torch.FloatTensor
+
+
+class UNet2DConditionModel(ModelMixin, ConfigMixin):
+    r"""
+    UNet2DConditionModel is a conditional 2D UNet model that takes in a noisy sample, conditional state, and a timestep
+    and returns sample shaped output.
+
+    This model inherits from [`ModelMixin`]. Check the superclass documentation for the generic methods the library
+    implements for all the model (such as downloading or saving, etc.)
+
+    Parameters:
+        sample_size (`int`, *optional*): The size of the input sample.
+        in_channels (`int`, *optional*, defaults to 4): The number of channels in the input sample.
+        out_channels (`int`, *optional*, defaults to 4): The number of channels in the output.
+        center_input_sample (`bool`, *optional*, defaults to `False`): Whether to center the input sample.
+        flip_sin_to_cos (`bool`, *optional*, defaults to `False`):
+            Whether to flip the sin to cos in the time embedding.
+        freq_shift (`int`, *optional*, defaults to 0): The frequency shift to apply to the time embedding.
+        down_block_types (`Tuple[str]`, *optional*, defaults to `("CrossAttnDownBlock2D", "CrossAttnDownBlock2D", "CrossAttnDownBlock2D", "DownBlock2D")`):
+            The tuple of downsample blocks to use.
+        up_block_types (`Tuple[str]`, *optional*, defaults to `("UpBlock2D", "CrossAttnUpBlock2D", "CrossAttnUpBlock2D", "CrossAttnUpBlock2D",)`):
+            The tuple of upsample blocks to use.
+        block_out_channels (`Tuple[int]`, *optional*, defaults to `(320, 640, 1280, 1280)`):
+            The tuple of output channels for each block.
+        layers_per_block (`int`, *optional*, defaults to 2): The number of layers per block.
+        downsample_padding (`int`, *optional*, defaults to 1): The padding to use for the downsampling convolution.
+        mid_block_scale_factor (`float`, *optional*, defaults to 1.0): The scale factor to use for the mid block.
+        act_fn (`str`, *optional*, defaults to `"silu"`): The activation function to use.
+        norm_num_groups (`int`, *optional*, defaults to 32): The number of groups to use for the normalization.
+        norm_eps (`float`, *optional*, defaults to 1e-5): The epsilon to use for the normalization.
+        cross_attention_dim (`int`, *optional*, defaults to 1280): The dimension of the cross attention features.
+        attention_head_dim (`int`, *optional*, defaults to 8): The dimension of the attention heads.
+    """
+
+    @register_to_config
+    def __init__(
+        self,
+        sample_size: Optional[int] = None,
+        in_channels: int = 4,
+        out_channels: int = 4,
+        center_input_sample: bool = False,
+        flip_sin_to_cos: bool = True,
+        freq_shift: int = 0,
+        down_block_types: Tuple[str] = (
+            "CrossAttnDownBlock2D",
+            "CrossAttnDownBlock2D",
+            "CrossAttnDownBlock2D",
+            "DownBlock2D",
+        ),
+        up_block_types: Tuple[str] = ("UpBlock2D", "CrossAttnUpBlock2D", "CrossAttnUpBlock2D", "CrossAttnUpBlock2D"),
+        block_out_channels: Tuple[int] = (320, 640, 1280, 1280),
+        layers_per_block: int = 2,
+        downsample_padding: int = 1,
+        mid_block_scale_factor: float = 1,
+        act_fn: str = "silu",
+        norm_num_groups: int = 32,
+        norm_eps: float = 1e-5,
+        cross_attention_dim: int = 1280,
+        attention_head_dim: int = 8,
+    ):
+        super().__init__()
+
+        self.sample_size = sample_size
+        time_embed_dim = block_out_channels[0] * 4
+
+        # input
+        self.conv_in = nn.Conv2d(in_channels, block_out_channels[0], kernel_size=3, padding=(1, 1))
+
+        # time
+        self.time_proj = Timesteps(block_out_channels[0], flip_sin_to_cos, freq_shift)
+        timestep_input_dim = block_out_channels[0]
+
+        self.time_embedding = TimestepEmbedding(timestep_input_dim, time_embed_dim)
+
+        self.down_blocks = nn.ModuleList([])
+        self.mid_block = None
+        self.up_blocks = nn.ModuleList([])
+
+        # down
+        output_channel = block_out_channels[0]
+        for i, down_block_type in enumerate(down_block_types):
+            input_channel = output_channel
+            output_channel = block_out_channels[i]
+            is_final_block = i == len(block_out_channels) - 1
+
+            down_block = get_down_block(
+                down_block_type,
+                num_layers=layers_per_block,
+                in_channels=input_channel,
+                out_channels=output_channel,
+                temb_channels=time_embed_dim,
+                add_downsample=not is_final_block,
+                resnet_eps=norm_eps,
+                resnet_act_fn=act_fn,
+                cross_attention_dim=cross_attention_dim,
+                attn_num_head_channels=attention_head_dim,
+                downsample_padding=downsample_padding,
+            )
+            self.down_blocks.append(down_block)
+
+        # mid
+        self.mid_block = UNetMidBlock2DCrossAttn(
+            in_channels=block_out_channels[-1],
+            temb_channels=time_embed_dim,
+            resnet_eps=norm_eps,
+            resnet_act_fn=act_fn,
+            output_scale_factor=mid_block_scale_factor,
+            resnet_time_scale_shift="default",
+            cross_attention_dim=cross_attention_dim,
+            attn_num_head_channels=attention_head_dim,
+            resnet_groups=norm_num_groups,
+        )
+
+        # up
+        reversed_block_out_channels = list(reversed(block_out_channels))
+        output_channel = reversed_block_out_channels[0]
+        for i, up_block_type in enumerate(up_block_types):
+            prev_output_channel = output_channel
+            output_channel = reversed_block_out_channels[i]
+            input_channel = reversed_block_out_channels[min(i + 1, len(block_out_channels) - 1)]
+
+            is_final_block = i == len(block_out_channels) - 1
+
+            up_block = get_up_block(
+                up_block_type,
+                num_layers=layers_per_block + 1,
+                in_channels=input_channel,
+                out_channels=output_channel,
+                prev_output_channel=prev_output_channel,
+                temb_channels=time_embed_dim,
+                add_upsample=not is_final_block,
+                resnet_eps=norm_eps,
+                resnet_act_fn=act_fn,
+                cross_attention_dim=cross_attention_dim,
+                attn_num_head_channels=attention_head_dim,
+            )
+            self.up_blocks.append(up_block)
+            prev_output_channel = output_channel
+
+        # out
+        self.conv_norm_out = nn.GroupNorm(num_channels=block_out_channels[0], num_groups=norm_num_groups, eps=norm_eps)
+        self.conv_act = nn.SiLU()
+        self.conv_out = nn.Conv2d(block_out_channels[0], out_channels, 3, padding=1)
+
+    def set_attention_slice(self, slice_size):
+        if slice_size is not None and self.config.attention_head_dim % slice_size != 0:
+            raise ValueError(
+                f"Make sure slice_size {slice_size} is a divisor of "
+                f"the number of heads used in cross_attention {self.config.attention_head_dim}"
+            )
+        if slice_size is not None and slice_size > self.config.attention_head_dim:
+            raise ValueError(
+                f"Chunk_size {slice_size} has to be smaller or equal to "
+                f"the number of heads used in cross_attention {self.config.attention_head_dim}"
+            )
+
+        for block in self.down_blocks:
+            if hasattr(block, "attentions") and block.attentions is not None:
+                block.set_attention_slice(slice_size)
+
+        self.mid_block.set_attention_slice(slice_size)
+
+        for block in self.up_blocks:
+            if hasattr(block, "attentions") and block.attentions is not None:
+                block.set_attention_slice(slice_size)
+
+    def forward(
+        self,
+        sample: torch.FloatTensor,
+        timestep: Union[torch.Tensor, float, int],
+        encoder_hidden_states: torch.Tensor,
+        return_dict: bool = True,
+    ) -> Union[UNet2DConditionOutput, Tuple]:
+        """r
+        Args:
+            sample (`torch.FloatTensor`): (batch, channel, height, width) noisy inputs tensor
+            timestep (`torch.FloatTensor` or `float` or `int): (batch) timesteps
+            encoder_hidden_states (`torch.FloatTensor`): (batch, channel, height, width) encoder hidden states
+            return_dict (`bool`, *optional*, defaults to `True`):
+                Whether or not to return a [`models.unet_2d_condition.UNet2DConditionOutput`] instead of a plain tuple.
+
+        Returns:
+            [`~models.unet_2d_condition.UNet2DConditionOutput`] or `tuple`:
+            [`~models.unet_2d_condition.UNet2DConditionOutput`] if `return_dict` is True, otherwise a `tuple`. When
+            returning a tuple, the first element is the sample tensor.
+        """
+        # 0. center input if necessary
+        if self.config.center_input_sample:
+            sample = 2 * sample - 1.0
+
+        # 1. time
+        timesteps = timestep
+        if not torch.is_tensor(timesteps):
+            timesteps = torch.tensor([timesteps], dtype=torch.long, device=sample.device)
+        elif torch.is_tensor(timesteps) and len(timesteps.shape) == 0:
+            timesteps = timesteps.to(dtype=torch.float32)
+            timesteps = timesteps[None].to(device=sample.device)
+
+        # broadcast to batch dimension in a way that's compatible with ONNX/Core ML
+        timesteps = timesteps.expand(sample.shape[0])
+
+        t_emb = self.time_proj(timesteps)
+        emb = self.time_embedding(t_emb)
+
+        # 2. pre-process
+        sample = self.conv_in(sample)
+
+        # 3. down
+        down_block_res_samples = (sample,)
+        for downsample_block in self.down_blocks:
+            if hasattr(downsample_block, "attentions") and downsample_block.attentions is not None:
+                sample, res_samples = downsample_block(
+                    hidden_states=sample, temb=emb, encoder_hidden_states=encoder_hidden_states
+                )
+            else:
+                sample, res_samples = downsample_block(hidden_states=sample, temb=emb)
+
+            down_block_res_samples += res_samples
+
+        # 4. mid
+        sample = self.mid_block(sample, emb, encoder_hidden_states=encoder_hidden_states)
+
+        # 5. up
+        for upsample_block in self.up_blocks:
+            res_samples = down_block_res_samples[-len(upsample_block.resnets) :]
+            down_block_res_samples = down_block_res_samples[: -len(upsample_block.resnets)]
+
+            if hasattr(upsample_block, "attentions") and upsample_block.attentions is not None:
+                sample = upsample_block(
+                    hidden_states=sample,
+                    temb=emb,
+                    res_hidden_states_tuple=res_samples,
+                    encoder_hidden_states=encoder_hidden_states,
+                )
+            else:
+                sample = upsample_block(hidden_states=sample, temb=emb, res_hidden_states_tuple=res_samples)
+
+        # 6. post-process
+        # make sure hidden states is in float32
+        # when running in half-precision
+        sample = self.conv_norm_out(sample.float()).type(sample.dtype)
+        sample = self.conv_act(sample)
+        sample = self.conv_out(sample)
+
+        return sample
+
+        if not return_dict:
+            return (sample,)
+
+        return UNet2DConditionOutput(sample=sample)

diffusers/models/unet_blocks.py

@@ -0,0 +1,1484 @@
+# Copyright 2022 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+
+import numpy as np
+
+# limitations under the License.
+import torch
+from torch import nn
+
+from .attention import AttentionBlock, SpatialTransformer
+from .resnet import Downsample2D, FirDownsample2D, FirUpsample2D, ResnetBlock2D, Upsample2D
+
+
+def get_down_block(
+    down_block_type,
+    num_layers,
+    in_channels,
+    out_channels,
+    temb_channels,
+    add_downsample,
+    resnet_eps,
+    resnet_act_fn,
+    attn_num_head_channels,
+    cross_attention_dim=None,
+    downsample_padding=None,
+):
+    down_block_type = down_block_type[7:] if down_block_type.startswith("UNetRes") else down_block_type
+    print(down_block_type)
+    if down_block_type == "DownBlock2D":
+        return DownBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            temb_channels=temb_channels,
+            add_downsample=add_downsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            downsample_padding=downsample_padding,
+        )
+    elif down_block_type == "AttnDownBlock2D":
+        return AttnDownBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            temb_channels=temb_channels,
+            add_downsample=add_downsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            downsample_padding=downsample_padding,
+            attn_num_head_channels=attn_num_head_channels,
+        )
+    elif down_block_type == "CrossAttnDownBlock2D":
+        if cross_attention_dim is None:
+            raise ValueError("cross_attention_dim must be specified for CrossAttnDownBlock2D")
+        return CrossAttnDownBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            temb_channels=temb_channels,
+            add_downsample=add_downsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            downsample_padding=downsample_padding,
+            cross_attention_dim=cross_attention_dim,
+            attn_num_head_channels=attn_num_head_channels,
+        )
+    elif down_block_type == "SkipDownBlock2D":
+        return SkipDownBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            temb_channels=temb_channels,
+            add_downsample=add_downsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            downsample_padding=downsample_padding,
+        )
+    elif down_block_type == "AttnSkipDownBlock2D":
+        return AttnSkipDownBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            temb_channels=temb_channels,
+            add_downsample=add_downsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            downsample_padding=downsample_padding,
+            attn_num_head_channels=attn_num_head_channels,
+        )
+    elif down_block_type == "DownEncoderBlock2D":
+        return DownEncoderBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            add_downsample=add_downsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            downsample_padding=downsample_padding,
+        )
+
+
+def get_up_block(
+    up_block_type,
+    num_layers,
+    in_channels,
+    out_channels,
+    prev_output_channel,
+    temb_channels,
+    add_upsample,
+    resnet_eps,
+    resnet_act_fn,
+    attn_num_head_channels,
+    cross_attention_dim=None,
+):
+    up_block_type = up_block_type[7:] if up_block_type.startswith("UNetRes") else up_block_type
+    print(up_block_type)
+    if up_block_type == "UpBlock2D":
+        return UpBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            prev_output_channel=prev_output_channel,
+            temb_channels=temb_channels,
+            add_upsample=add_upsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+        )
+    elif up_block_type == "CrossAttnUpBlock2D":
+        if cross_attention_dim is None:
+            raise ValueError("cross_attention_dim must be specified for CrossAttnUpBlock2D")
+        return CrossAttnUpBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            prev_output_channel=prev_output_channel,
+            temb_channels=temb_channels,
+            add_upsample=add_upsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            cross_attention_dim=cross_attention_dim,
+            attn_num_head_channels=attn_num_head_channels,
+        )
+    elif up_block_type == "AttnUpBlock2D":
+        return AttnUpBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            prev_output_channel=prev_output_channel,
+            temb_channels=temb_channels,
+            add_upsample=add_upsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            attn_num_head_channels=attn_num_head_channels,
+        )
+    elif up_block_type == "SkipUpBlock2D":
+        return SkipUpBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            prev_output_channel=prev_output_channel,
+            temb_channels=temb_channels,
+            add_upsample=add_upsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+        )
+    elif up_block_type == "AttnSkipUpBlock2D":
+        return AttnSkipUpBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            prev_output_channel=prev_output_channel,
+            temb_channels=temb_channels,
+            add_upsample=add_upsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+            attn_num_head_channels=attn_num_head_channels,
+        )
+    elif up_block_type == "UpDecoderBlock2D":
+        return UpDecoderBlock2D(
+            num_layers=num_layers,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            add_upsample=add_upsample,
+            resnet_eps=resnet_eps,
+            resnet_act_fn=resnet_act_fn,
+        )
+    raise ValueError(f"{up_block_type} does not exist.")
+
+
+class UNetMidBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        attention_type="default",
+        output_scale_factor=1.0,
+        **kwargs,
+    ):
+        super().__init__()
+
+        self.attention_type = attention_type
+        resnet_groups = resnet_groups if resnet_groups is not None else min(in_channels // 4, 32)
+
+        # there is always at least one resnet
+        resnets = [
+            ResnetBlock2D(
+                in_channels=in_channels,
+                out_channels=in_channels,
+                temb_channels=temb_channels,
+                eps=resnet_eps,
+                groups=resnet_groups,
+                dropout=dropout,
+                time_embedding_norm=resnet_time_scale_shift,
+                non_linearity=resnet_act_fn,
+                output_scale_factor=output_scale_factor,
+                pre_norm=resnet_pre_norm,
+            )
+        ]
+        attentions = []
+
+        for _ in range(num_layers):
+            attentions.append(
+                AttentionBlock(
+                    in_channels,
+                    num_head_channels=attn_num_head_channels,
+                    rescale_output_factor=output_scale_factor,
+                    eps=resnet_eps,
+                    num_groups=resnet_groups,
+                )
+            )
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=in_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+    def forward(self, hidden_states, temb=None, encoder_states=None):
+        hidden_states = self.resnets[0](hidden_states, temb)
+        print(self.attention_type)
+        for attn, resnet in zip(self.attentions, self.resnets[1:]):
+            if self.attention_type == "default":
+                hidden_states = attn(hidden_states)
+            else:
+                hidden_states = attn(hidden_states, encoder_states)
+            hidden_states = resnet(hidden_states, temb)
+
+        return hidden_states
+
+
+class UNetMidBlock2DCrossAttn(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        attention_type="default",
+        output_scale_factor=1.0,
+        cross_attention_dim=1280,
+        **kwargs,
+    ):
+        super().__init__()
+
+        self.attention_type = attention_type
+        self.attn_num_head_channels = attn_num_head_channels
+        resnet_groups = resnet_groups if resnet_groups is not None else min(in_channels // 4, 32)
+
+        # there is always at least one resnet
+        resnets = [
+            ResnetBlock2D(
+                in_channels=in_channels,
+                out_channels=in_channels,
+                temb_channels=temb_channels,
+                eps=resnet_eps,
+                groups=resnet_groups,
+                dropout=dropout,
+                time_embedding_norm=resnet_time_scale_shift,
+                non_linearity=resnet_act_fn,
+                output_scale_factor=output_scale_factor,
+                pre_norm=resnet_pre_norm,
+            )
+        ]
+        attentions = []
+
+        for _ in range(num_layers):
+            attentions.append(
+                SpatialTransformer(
+                    in_channels,
+                    attn_num_head_channels,
+                    in_channels // attn_num_head_channels,
+                    depth=1,
+                    context_dim=cross_attention_dim,
+                )
+            )
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=in_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+    def set_attention_slice(self, slice_size):
+        if slice_size is not None and self.attn_num_head_channels % slice_size != 0:
+            raise ValueError(
+                f"Make sure slice_size {slice_size} is a divisor of "
+                f"the number of heads used in cross_attention {self.attn_num_head_channels}"
+            )
+        if slice_size is not None and slice_size > self.attn_num_head_channels:
+            raise ValueError(
+                f"Chunk_size {slice_size} has to be smaller or equal to "
+                f"the number of heads used in cross_attention {self.attn_num_head_channels}"
+            )
+
+        for attn in self.attentions:
+            attn._set_attention_slice(slice_size)
+
+    def forward(self, hidden_states, temb=None, encoder_hidden_states=None):
+        hidden_states = self.resnets[0](hidden_states, temb)
+        for attn, resnet in zip(self.attentions, self.resnets[1:]):
+            hidden_states = attn(hidden_states, encoder_hidden_states)
+            hidden_states = resnet(hidden_states, temb)
+
+        return hidden_states
+
+
+class AttnDownBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        attention_type="default",
+        output_scale_factor=1.0,
+        downsample_padding=1,
+        add_downsample=True,
+    ):
+        super().__init__()
+        resnets = []
+        attentions = []
+
+        self.attention_type = attention_type
+
+        for i in range(num_layers):
+            in_channels = in_channels if i == 0 else out_channels
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+            attentions.append(
+                AttentionBlock(
+                    out_channels,
+                    num_head_channels=attn_num_head_channels,
+                    rescale_output_factor=output_scale_factor,
+                    eps=resnet_eps,
+                )
+            )
+
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_downsample:
+            self.downsamplers = nn.ModuleList(
+                [
+                    Downsample2D(
+                        in_channels, use_conv=True, out_channels=out_channels, padding=downsample_padding, name="op"
+                    )
+                ]
+            )
+        else:
+            self.downsamplers = None
+
+    def forward(self, hidden_states, temb=None):
+        output_states = ()
+
+        for resnet, attn in zip(self.resnets, self.attentions):
+            hidden_states = resnet(hidden_states, temb)
+            hidden_states = attn(hidden_states)
+            output_states += (hidden_states,)
+
+        if self.downsamplers is not None:
+            for downsampler in self.downsamplers:
+                hidden_states = downsampler(hidden_states)
+
+            output_states += (hidden_states,)
+
+        return hidden_states, output_states
+
+
+class CrossAttnDownBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        cross_attention_dim=1280,
+        attention_type="default",
+        output_scale_factor=1.0,
+        downsample_padding=1,
+        add_downsample=True,
+    ):
+        super().__init__()
+        resnets = []
+        attentions = []
+
+        self.attention_type = attention_type
+        self.attn_num_head_channels = attn_num_head_channels
+
+        for i in range(num_layers):
+            in_channels = in_channels if i == 0 else out_channels
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+            attentions.append(
+                SpatialTransformer(
+                    out_channels,
+                    attn_num_head_channels,
+                    out_channels // attn_num_head_channels,
+                    depth=1,
+                    context_dim=cross_attention_dim,
+                )
+            )
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_downsample:
+            self.downsamplers = nn.ModuleList(
+                [
+                    Downsample2D(
+                        in_channels, use_conv=True, out_channels=out_channels, padding=downsample_padding, name="op"
+                    )
+                ]
+            )
+        else:
+            self.downsamplers = None
+
+    def set_attention_slice(self, slice_size):
+        if slice_size is not None and self.attn_num_head_channels % slice_size != 0:
+            raise ValueError(
+                f"Make sure slice_size {slice_size} is a divisor of "
+                f"the number of heads used in cross_attention {self.attn_num_head_channels}"
+            )
+        if slice_size is not None and slice_size > self.attn_num_head_channels:
+            raise ValueError(
+                f"Chunk_size {slice_size} has to be smaller or equal to "
+                f"the number of heads used in cross_attention {self.attn_num_head_channels}"
+            )
+
+        for attn in self.attentions:
+            attn._set_attention_slice(slice_size)
+
+    def forward(self, hidden_states, temb=None, encoder_hidden_states=None):
+        output_states = ()
+
+        for resnet, attn in zip(self.resnets, self.attentions):
+            hidden_states = resnet(hidden_states, temb)
+            hidden_states = attn(hidden_states, context=encoder_hidden_states)
+            output_states += (hidden_states,)
+
+        if self.downsamplers is not None:
+            for downsampler in self.downsamplers:
+                hidden_states = downsampler(hidden_states)
+
+            output_states += (hidden_states,)
+
+        return hidden_states, output_states
+
+
+class DownBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        output_scale_factor=1.0,
+        add_downsample=True,
+        downsample_padding=1,
+    ):
+        super().__init__()
+        resnets = []
+
+        for i in range(num_layers):
+            in_channels = in_channels if i == 0 else out_channels
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_downsample:
+            self.downsamplers = nn.ModuleList(
+                [
+                    Downsample2D(
+                        in_channels, use_conv=True, out_channels=out_channels, padding=downsample_padding, name="op"
+                    )
+                ]
+            )
+        else:
+            self.downsamplers = None
+
+    def forward(self, hidden_states, temb=None):
+        output_states = ()
+
+        for resnet in self.resnets:
+            hidden_states = resnet(hidden_states, temb)
+            output_states += (hidden_states,)
+
+        if self.downsamplers is not None:
+            for downsampler in self.downsamplers:
+                hidden_states = downsampler(hidden_states)
+
+            output_states += (hidden_states,)
+
+        return hidden_states, output_states
+
+
+class DownEncoderBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        output_scale_factor=1.0,
+        add_downsample=True,
+        downsample_padding=1,
+    ):
+        super().__init__()
+        resnets = []
+
+        for i in range(num_layers):
+            in_channels = in_channels if i == 0 else out_channels
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=out_channels,
+                    temb_channels=None,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_downsample:
+            self.downsamplers = nn.ModuleList(
+                [
+                    Downsample2D(
+                        in_channels, use_conv=True, out_channels=out_channels, padding=downsample_padding, name="op"
+                    )
+                ]
+            )
+        else:
+            self.downsamplers = None
+
+    def forward(self, hidden_states):
+        for resnet in self.resnets:
+            hidden_states = resnet(hidden_states, temb=None)
+
+        if self.downsamplers is not None:
+            for downsampler in self.downsamplers:
+                hidden_states = downsampler(hidden_states)
+
+        return hidden_states
+
+
+class AttnDownEncoderBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        output_scale_factor=1.0,
+        add_downsample=True,
+        downsample_padding=1,
+    ):
+        super().__init__()
+        resnets = []
+        attentions = []
+
+        for i in range(num_layers):
+            in_channels = in_channels if i == 0 else out_channels
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=out_channels,
+                    temb_channels=None,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+            attentions.append(
+                AttentionBlock(
+                    out_channels,
+                    num_head_channels=attn_num_head_channels,
+                    rescale_output_factor=output_scale_factor,
+                    eps=resnet_eps,
+                    num_groups=resnet_groups,
+                )
+            )
+
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_downsample:
+            self.downsamplers = nn.ModuleList(
+                [
+                    Downsample2D(
+                        in_channels, use_conv=True, out_channels=out_channels, padding=downsample_padding, name="op"
+                    )
+                ]
+            )
+        else:
+            self.downsamplers = None
+
+    def forward(self, hidden_states):
+        for resnet, attn in zip(self.resnets, self.attentions):
+            hidden_states = resnet(hidden_states, temb=None)
+            hidden_states = attn(hidden_states)
+
+        if self.downsamplers is not None:
+            for downsampler in self.downsamplers:
+                hidden_states = downsampler(hidden_states)
+
+        return hidden_states
+
+
+class AttnSkipDownBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        attention_type="default",
+        output_scale_factor=np.sqrt(2.0),
+        downsample_padding=1,
+        add_downsample=True,
+    ):
+        super().__init__()
+        self.attentions = nn.ModuleList([])
+        self.resnets = nn.ModuleList([])
+
+        self.attention_type = attention_type
+
+        for i in range(num_layers):
+            in_channels = in_channels if i == 0 else out_channels
+            self.resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=min(in_channels // 4, 32),
+                    groups_out=min(out_channels // 4, 32),
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+            self.attentions.append(
+                AttentionBlock(
+                    out_channels,
+                    num_head_channels=attn_num_head_channels,
+                    rescale_output_factor=output_scale_factor,
+                    eps=resnet_eps,
+                )
+            )
+
+        if add_downsample:
+            self.resnet_down = ResnetBlock2D(
+                in_channels=out_channels,
+                out_channels=out_channels,
+                temb_channels=temb_channels,
+                eps=resnet_eps,
+                groups=min(out_channels // 4, 32),
+                dropout=dropout,
+                time_embedding_norm=resnet_time_scale_shift,
+                non_linearity=resnet_act_fn,
+                output_scale_factor=output_scale_factor,
+                pre_norm=resnet_pre_norm,
+                use_nin_shortcut=True,
+                down=True,
+                kernel="fir",
+            )
+            self.downsamplers = nn.ModuleList([FirDownsample2D(in_channels, out_channels=out_channels)])
+            self.skip_conv = nn.Conv2d(3, out_channels, kernel_size=(1, 1), stride=(1, 1))
+        else:
+            self.resnet_down = None
+            self.downsamplers = None
+            self.skip_conv = None
+
+    def forward(self, hidden_states, temb=None, skip_sample=None):
+        output_states = ()
+
+        for resnet, attn in zip(self.resnets, self.attentions):
+            hidden_states = resnet(hidden_states, temb)
+            hidden_states = attn(hidden_states)
+            output_states += (hidden_states,)
+
+        if self.downsamplers is not None:
+            hidden_states = self.resnet_down(hidden_states, temb)
+            for downsampler in self.downsamplers:
+                skip_sample = downsampler(skip_sample)
+
+            hidden_states = self.skip_conv(skip_sample) + hidden_states
+
+            output_states += (hidden_states,)
+
+        return hidden_states, output_states, skip_sample
+
+
+class SkipDownBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_pre_norm: bool = True,
+        output_scale_factor=np.sqrt(2.0),
+        add_downsample=True,
+        downsample_padding=1,
+    ):
+        super().__init__()
+        self.resnets = nn.ModuleList([])
+
+        for i in range(num_layers):
+            in_channels = in_channels if i == 0 else out_channels
+            self.resnets.append(
+                ResnetBlock2D(
+                    in_channels=in_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=min(in_channels // 4, 32),
+                    groups_out=min(out_channels // 4, 32),
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        if add_downsample:
+            self.resnet_down = ResnetBlock2D(
+                in_channels=out_channels,
+                out_channels=out_channels,
+                temb_channels=temb_channels,
+                eps=resnet_eps,
+                groups=min(out_channels // 4, 32),
+                dropout=dropout,
+                time_embedding_norm=resnet_time_scale_shift,
+                non_linearity=resnet_act_fn,
+                output_scale_factor=output_scale_factor,
+                pre_norm=resnet_pre_norm,
+                use_nin_shortcut=True,
+                down=True,
+                kernel="fir",
+            )
+            self.downsamplers = nn.ModuleList([FirDownsample2D(in_channels, out_channels=out_channels)])
+            self.skip_conv = nn.Conv2d(3, out_channels, kernel_size=(1, 1), stride=(1, 1))
+        else:
+            self.resnet_down = None
+            self.downsamplers = None
+            self.skip_conv = None
+
+    def forward(self, hidden_states, temb=None, skip_sample=None):
+        output_states = ()
+
+        for resnet in self.resnets:
+            hidden_states = resnet(hidden_states, temb)
+            output_states += (hidden_states,)
+
+        if self.downsamplers is not None:
+            hidden_states = self.resnet_down(hidden_states, temb)
+            for downsampler in self.downsamplers:
+                skip_sample = downsampler(skip_sample)
+
+            hidden_states = self.skip_conv(skip_sample) + hidden_states
+
+            output_states += (hidden_states,)
+
+        return hidden_states, output_states, skip_sample
+
+
+class AttnUpBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        prev_output_channel: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attention_type="default",
+        attn_num_head_channels=1,
+        output_scale_factor=1.0,
+        add_upsample=True,
+    ):
+        super().__init__()
+        resnets = []
+        attentions = []
+
+        self.attention_type = attention_type
+
+        for i in range(num_layers):
+            res_skip_channels = in_channels if (i == num_layers - 1) else out_channels
+            resnet_in_channels = prev_output_channel if i == 0 else out_channels
+
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=resnet_in_channels + res_skip_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+            attentions.append(
+                AttentionBlock(
+                    out_channels,
+                    num_head_channels=attn_num_head_channels,
+                    rescale_output_factor=output_scale_factor,
+                    eps=resnet_eps,
+                )
+            )
+
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_upsample:
+            self.upsamplers = nn.ModuleList([Upsample2D(out_channels, use_conv=True, out_channels=out_channels)])
+        else:
+            self.upsamplers = None
+
+    def forward(self, hidden_states, res_hidden_states_tuple, temb=None):
+        for resnet, attn in zip(self.resnets, self.attentions):
+
+            # pop res hidden states
+            res_hidden_states = res_hidden_states_tuple[-1]
+            res_hidden_states_tuple = res_hidden_states_tuple[:-1]
+            hidden_states = torch.cat([hidden_states, res_hidden_states], dim=1)
+
+            hidden_states = resnet(hidden_states, temb)
+            hidden_states = attn(hidden_states)
+
+        if self.upsamplers is not None:
+            for upsampler in self.upsamplers:
+                hidden_states = upsampler(hidden_states)
+
+        return hidden_states
+
+
+class CrossAttnUpBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        prev_output_channel: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        cross_attention_dim=1280,
+        attention_type="default",
+        output_scale_factor=1.0,
+        downsample_padding=1,
+        add_upsample=True,
+    ):
+        super().__init__()
+        resnets = []
+        attentions = []
+
+        self.attention_type = attention_type
+        self.attn_num_head_channels = attn_num_head_channels
+
+        for i in range(num_layers):
+            res_skip_channels = in_channels if (i == num_layers - 1) else out_channels
+            resnet_in_channels = prev_output_channel if i == 0 else out_channels
+
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=resnet_in_channels + res_skip_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+            attentions.append(
+                SpatialTransformer(
+                    out_channels,
+                    attn_num_head_channels,
+                    out_channels // attn_num_head_channels,
+                    depth=1,
+                    context_dim=cross_attention_dim,
+                )
+            )
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_upsample:
+            self.upsamplers = nn.ModuleList([Upsample2D(out_channels, use_conv=True, out_channels=out_channels)])
+        else:
+            self.upsamplers = None
+
+    def set_attention_slice(self, slice_size):
+        if slice_size is not None and self.attn_num_head_channels % slice_size != 0:
+            raise ValueError(
+                f"Make sure slice_size {slice_size} is a divisor of "
+                f"the number of heads used in cross_attention {self.attn_num_head_channels}"
+            )
+        if slice_size is not None and slice_size > self.attn_num_head_channels:
+            raise ValueError(
+                f"Chunk_size {slice_size} has to be smaller or equal to "
+                f"the number of heads used in cross_attention {self.attn_num_head_channels}"
+            )
+
+        for attn in self.attentions:
+            attn._set_attention_slice(slice_size)
+
+    def forward(self, hidden_states, res_hidden_states_tuple, temb=None, encoder_hidden_states=None):
+        for resnet, attn in zip(self.resnets, self.attentions):
+
+            # pop res hidden states
+            res_hidden_states = res_hidden_states_tuple[-1]
+            res_hidden_states_tuple = res_hidden_states_tuple[:-1]
+            hidden_states = torch.cat([hidden_states, res_hidden_states], dim=1)
+
+            hidden_states = resnet(hidden_states, temb)
+            hidden_states = attn(hidden_states, context=encoder_hidden_states)
+
+        if self.upsamplers is not None:
+            for upsampler in self.upsamplers:
+                hidden_states = upsampler(hidden_states)
+
+        return hidden_states
+
+
+class UpBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        prev_output_channel: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        output_scale_factor=1.0,
+        add_upsample=True,
+    ):
+        super().__init__()
+        resnets = []
+
+        for i in range(num_layers):
+            res_skip_channels = in_channels if (i == num_layers - 1) else out_channels
+            resnet_in_channels = prev_output_channel if i == 0 else out_channels
+
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=resnet_in_channels + res_skip_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_upsample:
+            self.upsamplers = nn.ModuleList([Upsample2D(out_channels, use_conv=True, out_channels=out_channels)])
+        else:
+            self.upsamplers = None
+
+    def forward(self, hidden_states, res_hidden_states_tuple, temb=None):
+        for resnet in self.resnets:
+
+            # pop res hidden states
+            res_hidden_states = res_hidden_states_tuple[-1]
+            res_hidden_states_tuple = res_hidden_states_tuple[:-1]
+            hidden_states = torch.cat([hidden_states, res_hidden_states], dim=1)
+
+            hidden_states = resnet(hidden_states, temb)
+
+        if self.upsamplers is not None:
+            for upsampler in self.upsamplers:
+                hidden_states = upsampler(hidden_states)
+
+        return hidden_states
+
+
+class UpDecoderBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        output_scale_factor=1.0,
+        add_upsample=True,
+    ):
+        super().__init__()
+        resnets = []
+
+        for i in range(num_layers):
+            input_channels = in_channels if i == 0 else out_channels
+
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=input_channels,
+                    out_channels=out_channels,
+                    temb_channels=None,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_upsample:
+            self.upsamplers = nn.ModuleList([Upsample2D(out_channels, use_conv=True, out_channels=out_channels)])
+        else:
+            self.upsamplers = None
+
+    def forward(self, hidden_states):
+        for resnet in self.resnets:
+            hidden_states = resnet(hidden_states, temb=None)
+
+        if self.upsamplers is not None:
+            for upsampler in self.upsamplers:
+                hidden_states = upsampler(hidden_states)
+
+        return hidden_states
+
+
+class AttnUpDecoderBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_groups: int = 32,
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        output_scale_factor=1.0,
+        add_upsample=True,
+    ):
+        super().__init__()
+        resnets = []
+        attentions = []
+
+        for i in range(num_layers):
+            input_channels = in_channels if i == 0 else out_channels
+
+            resnets.append(
+                ResnetBlock2D(
+                    in_channels=input_channels,
+                    out_channels=out_channels,
+                    temb_channels=None,
+                    eps=resnet_eps,
+                    groups=resnet_groups,
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+            attentions.append(
+                AttentionBlock(
+                    out_channels,
+                    num_head_channels=attn_num_head_channels,
+                    rescale_output_factor=output_scale_factor,
+                    eps=resnet_eps,
+                    num_groups=resnet_groups,
+                )
+            )
+
+        self.attentions = nn.ModuleList(attentions)
+        self.resnets = nn.ModuleList(resnets)
+
+        if add_upsample:
+            self.upsamplers = nn.ModuleList([Upsample2D(out_channels, use_conv=True, out_channels=out_channels)])
+        else:
+            self.upsamplers = None
+
+    def forward(self, hidden_states):
+        for resnet, attn in zip(self.resnets, self.attentions):
+            hidden_states = resnet(hidden_states, temb=None)
+            hidden_states = attn(hidden_states)
+
+        if self.upsamplers is not None:
+            for upsampler in self.upsamplers:
+                hidden_states = upsampler(hidden_states)
+
+        return hidden_states
+
+
+class AttnSkipUpBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        prev_output_channel: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_pre_norm: bool = True,
+        attn_num_head_channels=1,
+        attention_type="default",
+        output_scale_factor=np.sqrt(2.0),
+        upsample_padding=1,
+        add_upsample=True,
+    ):
+        super().__init__()
+        self.attentions = nn.ModuleList([])
+        self.resnets = nn.ModuleList([])
+
+        self.attention_type = attention_type
+
+        for i in range(num_layers):
+            res_skip_channels = in_channels if (i == num_layers - 1) else out_channels
+            resnet_in_channels = prev_output_channel if i == 0 else out_channels
+
+            self.resnets.append(
+                ResnetBlock2D(
+                    in_channels=resnet_in_channels + res_skip_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=min(resnet_in_channels + res_skip_channels // 4, 32),
+                    groups_out=min(out_channels // 4, 32),
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.attentions.append(
+            AttentionBlock(
+                out_channels,
+                num_head_channels=attn_num_head_channels,
+                rescale_output_factor=output_scale_factor,
+                eps=resnet_eps,
+            )
+        )
+
+        self.upsampler = FirUpsample2D(in_channels, out_channels=out_channels)
+        if add_upsample:
+            self.resnet_up = ResnetBlock2D(
+                in_channels=out_channels,
+                out_channels=out_channels,
+                temb_channels=temb_channels,
+                eps=resnet_eps,
+                groups=min(out_channels // 4, 32),
+                groups_out=min(out_channels // 4, 32),
+                dropout=dropout,
+                time_embedding_norm=resnet_time_scale_shift,
+                non_linearity=resnet_act_fn,
+                output_scale_factor=output_scale_factor,
+                pre_norm=resnet_pre_norm,
+                use_nin_shortcut=True,
+                up=True,
+                kernel="fir",
+            )
+            self.skip_conv = nn.Conv2d(out_channels, 3, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
+            self.skip_norm = torch.nn.GroupNorm(
+                num_groups=min(out_channels // 4, 32), num_channels=out_channels, eps=resnet_eps, affine=True
+            )
+            self.act = nn.SiLU()
+        else:
+            self.resnet_up = None
+            self.skip_conv = None
+            self.skip_norm = None
+            self.act = None
+
+    def forward(self, hidden_states, res_hidden_states_tuple, temb=None, skip_sample=None):
+        for resnet in self.resnets:
+            # pop res hidden states
+            res_hidden_states = res_hidden_states_tuple[-1]
+            res_hidden_states_tuple = res_hidden_states_tuple[:-1]
+            hidden_states = torch.cat([hidden_states, res_hidden_states], dim=1)
+
+            hidden_states = resnet(hidden_states, temb)
+
+        hidden_states = self.attentions[0](hidden_states)
+
+        if skip_sample is not None:
+            skip_sample = self.upsampler(skip_sample)
+        else:
+            skip_sample = 0
+
+        if self.resnet_up is not None:
+            skip_sample_states = self.skip_norm(hidden_states)
+            skip_sample_states = self.act(skip_sample_states)
+            skip_sample_states = self.skip_conv(skip_sample_states)
+
+            skip_sample = skip_sample + skip_sample_states
+
+            hidden_states = self.resnet_up(hidden_states, temb)
+
+        return hidden_states, skip_sample
+
+
+class SkipUpBlock2D(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        prev_output_channel: int,
+        out_channels: int,
+        temb_channels: int,
+        dropout: float = 0.0,
+        num_layers: int = 1,
+        resnet_eps: float = 1e-6,
+        resnet_time_scale_shift: str = "default",
+        resnet_act_fn: str = "swish",
+        resnet_pre_norm: bool = True,
+        output_scale_factor=np.sqrt(2.0),
+        add_upsample=True,
+        upsample_padding=1,
+    ):
+        super().__init__()
+        self.resnets = nn.ModuleList([])
+
+        for i in range(num_layers):
+            res_skip_channels = in_channels if (i == num_layers - 1) else out_channels
+            resnet_in_channels = prev_output_channel if i == 0 else out_channels
+
+            self.resnets.append(
+                ResnetBlock2D(
+                    in_channels=resnet_in_channels + res_skip_channels,
+                    out_channels=out_channels,
+                    temb_channels=temb_channels,
+                    eps=resnet_eps,
+                    groups=min((resnet_in_channels + res_skip_channels) // 4, 32),
+                    groups_out=min(out_channels // 4, 32),
+                    dropout=dropout,
+                    time_embedding_norm=resnet_time_scale_shift,
+                    non_linearity=resnet_act_fn,
+                    output_scale_factor=output_scale_factor,
+                    pre_norm=resnet_pre_norm,
+                )
+            )
+
+        self.upsampler = FirUpsample2D(in_channels, out_channels=out_channels)
+        if add_upsample:
+            self.resnet_up = ResnetBlock2D(
+                in_channels=out_channels,
+                out_channels=out_channels,
+                temb_channels=temb_channels,
+                eps=resnet_eps,
+                groups=min(out_channels // 4, 32),
+                groups_out=min(out_channels // 4, 32),
+                dropout=dropout,
+                time_embedding_norm=resnet_time_scale_shift,
+                non_linearity=resnet_act_fn,
+                output_scale_factor=output_scale_factor,
+                pre_norm=resnet_pre_norm,
+                use_nin_shortcut=True,
+                up=True,
+                kernel="fir",
+            )
+            self.skip_conv = nn.Conv2d(out_channels, 3, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
+            self.skip_norm = torch.nn.GroupNorm(
+                num_groups=min(out_channels // 4, 32), num_channels=out_channels, eps=resnet_eps, affine=True
+            )
+            self.act = nn.SiLU()
+        else:
+            self.resnet_up = None
+            self.skip_conv = None
+            self.skip_norm = None
+            self.act = None
+
+    def forward(self, hidden_states, res_hidden_states_tuple, temb=None, skip_sample=None):
+        for resnet in self.resnets:
+            # pop res hidden states
+            res_hidden_states = res_hidden_states_tuple[-1]
+            res_hidden_states_tuple = res_hidden_states_tuple[:-1]
+            hidden_states = torch.cat([hidden_states, res_hidden_states], dim=1)
+
+            hidden_states = resnet(hidden_states, temb)
+
+        if skip_sample is not None:
+            skip_sample = self.upsampler(skip_sample)
+        else:
+            skip_sample = 0
+
+        if self.resnet_up is not None:
+            skip_sample_states = self.skip_norm(hidden_states)
+            skip_sample_states = self.act(skip_sample_states)
+            skip_sample_states = self.skip_conv(skip_sample_states)
+
+            skip_sample = skip_sample + skip_sample_states
+
+            hidden_states = self.resnet_up(hidden_states, temb)
+
+        return hidden_states, skip_sample

diffusers/models/vae.py

@@ -0,0 +1,585 @@
+from dataclasses import dataclass
+from typing import Optional, Tuple, Union
+
+import numpy as np
+import torch
+import torch.nn as nn
+
+from ..configuration_utils import ConfigMixin, register_to_config
+from ..modeling_utils import ModelMixin
+from ..utils import BaseOutput
+from .unet_blocks import UNetMidBlock2D, get_down_block, get_up_block
+
+
+@dataclass
+class DecoderOutput(BaseOutput):
+    """
+    Output of decoding method.
+
+    Args:
+        sample (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
+            Decoded output sample of the model. Output of the last layer of the model.
+    """
+
+    sample: torch.FloatTensor
+
+
+@dataclass
+class VQEncoderOutput(BaseOutput):
+    """
+    Output of VQModel encoding method.
+
+    Args:
+        latents (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
+            Encoded output sample of the model. Output of the last layer of the model.
+    """
+
+    latents: torch.FloatTensor
+
+
+@dataclass
+class AutoencoderKLOutput(BaseOutput):
+    """
+    Output of AutoencoderKL encoding method.
+
+    Args:
+        latent_dist (`DiagonalGaussianDistribution`):
+            Encoded outputs of `Encoder` represented as the mean and logvar of `DiagonalGaussianDistribution`.
+            `DiagonalGaussianDistribution` allows for sampling latents from the distribution.
+    """
+
+    latent_dist: "DiagonalGaussianDistribution"
+
+
+class Encoder(nn.Module):
+    def __init__(
+        self,
+        in_channels=3,
+        out_channels=3,
+        down_block_types=("DownEncoderBlock2D",),
+        block_out_channels=(64,),
+        layers_per_block=2,
+        act_fn="silu",
+        double_z=True,
+    ):
+        super().__init__()
+        self.layers_per_block = layers_per_block
+
+        self.conv_in = torch.nn.Conv2d(in_channels, block_out_channels[0], kernel_size=3, stride=1, padding=1)
+
+        self.mid_block = None
+        self.down_blocks = nn.ModuleList([])
+
+        # down
+        output_channel = block_out_channels[0]
+        for i, down_block_type in enumerate(down_block_types):
+            input_channel = output_channel
+            output_channel = block_out_channels[i]
+            is_final_block = i == len(block_out_channels) - 1
+
+            down_block = get_down_block(
+                down_block_type,
+                num_layers=self.layers_per_block,
+                in_channels=input_channel,
+                out_channels=output_channel,
+                add_downsample=not is_final_block,
+                resnet_eps=1e-6,
+                downsample_padding=0,
+                resnet_act_fn=act_fn,
+                attn_num_head_channels=None,
+                temb_channels=None,
+            )
+            self.down_blocks.append(down_block)
+
+        # mid
+        self.mid_block = UNetMidBlock2D(
+            in_channels=block_out_channels[-1],
+            resnet_eps=1e-6,
+            resnet_act_fn=act_fn,
+            output_scale_factor=1,
+            resnet_time_scale_shift="default",
+            attn_num_head_channels=None,
+            resnet_groups=32,
+            temb_channels=None,
+        )
+
+        # out
+        num_groups_out = 32
+        self.conv_norm_out = nn.GroupNorm(num_channels=block_out_channels[-1], num_groups=num_groups_out, eps=1e-6)
+        self.conv_act = nn.SiLU()
+
+        conv_out_channels = 2 * out_channels if double_z else out_channels
+        self.conv_out = nn.Conv2d(block_out_channels[-1], conv_out_channels, 3, padding=1)
+
+    def forward(self, x):
+        sample = x
+        sample = self.conv_in(sample)
+
+        # down
+        for down_block in self.down_blocks:
+            sample = down_block(sample)
+
+        # middle
+        sample = self.mid_block(sample)
+
+        # post-process
+        sample = self.conv_norm_out(sample)
+        sample = self.conv_act(sample)
+        sample = self.conv_out(sample)
+
+        return sample
+
+
+class Decoder(nn.Module):
+    def __init__(
+        self,
+        in_channels=3,
+        out_channels=3,
+        up_block_types=("UpDecoderBlock2D",),
+        block_out_channels=(64,),
+        layers_per_block=2,
+        act_fn="silu",
+    ):
+        super().__init__()
+        self.layers_per_block = layers_per_block
+
+        self.conv_in = nn.Conv2d(in_channels, block_out_channels[-1], kernel_size=3, stride=1, padding=1)
+
+        self.mid_block = None
+        self.up_blocks = nn.ModuleList([])
+
+        # mid
+        self.mid_block = UNetMidBlock2D(
+            in_channels=block_out_channels[-1],
+            resnet_eps=1e-6,
+            resnet_act_fn=act_fn,
+            output_scale_factor=1,
+            resnet_time_scale_shift="default",
+            attn_num_head_channels=None,
+            resnet_groups=32,
+            temb_channels=None,
+        )
+
+        # up
+        reversed_block_out_channels = list(reversed(block_out_channels))
+        output_channel = reversed_block_out_channels[0]
+        for i, up_block_type in enumerate(up_block_types):
+            prev_output_channel = output_channel
+            output_channel = reversed_block_out_channels[i]
+
+            is_final_block = i == len(block_out_channels) - 1
+
+            up_block = get_up_block(
+                up_block_type,
+                num_layers=self.layers_per_block + 1,
+                in_channels=prev_output_channel,
+                out_channels=output_channel,
+                prev_output_channel=None,
+                add_upsample=not is_final_block,
+                resnet_eps=1e-6,
+                resnet_act_fn=act_fn,
+                attn_num_head_channels=None,
+                temb_channels=None,
+            )
+            self.up_blocks.append(up_block)
+            prev_output_channel = output_channel
+
+        # out
+        num_groups_out = 32
+        self.conv_norm_out = nn.GroupNorm(num_channels=block_out_channels[0], num_groups=num_groups_out, eps=1e-6)
+        self.conv_act = nn.SiLU()
+        self.conv_out = nn.Conv2d(block_out_channels[0], out_channels, 3, padding=1)
+
+    def forward(self, z):
+        sample = z
+        sample = self.conv_in(sample)
+
+        # middle
+        sample = self.mid_block(sample)
+
+        # up
+        for up_block in self.up_blocks:
+            sample = up_block(sample)
+
+        # post-process
+        sample = self.conv_norm_out(sample)
+        sample = self.conv_act(sample)
+        sample = self.conv_out(sample)
+
+        return sample
+
+
+class VectorQuantizer(nn.Module):
+    """
+    Improved version over VectorQuantizer, can be used as a drop-in replacement. Mostly avoids costly matrix
+    multiplications and allows for post-hoc remapping of indices.
+    """
+
+    # NOTE: due to a bug the beta term was applied to the wrong term. for
+    # backwards compatibility we use the buggy version by default, but you can
+    # specify legacy=False to fix it.
+    def __init__(self, n_e, e_dim, beta, remap=None, unknown_index="random", sane_index_shape=False, legacy=True):
+        super().__init__()
+        self.n_e = n_e
+        self.e_dim = e_dim
+        self.beta = beta
+        self.legacy = legacy
+
+        self.embedding = nn.Embedding(self.n_e, self.e_dim)
+        self.embedding.weight.data.uniform_(-1.0 / self.n_e, 1.0 / self.n_e)
+
+        self.remap = remap
+        if self.remap is not None:
+            self.register_buffer("used", torch.tensor(np.load(self.remap)))
+            self.re_embed = self.used.shape[0]
+            self.unknown_index = unknown_index  # "random" or "extra" or integer
+            if self.unknown_index == "extra":
+                self.unknown_index = self.re_embed
+                self.re_embed = self.re_embed + 1
+            print(
+                f"Remapping {self.n_e} indices to {self.re_embed} indices. "
+                f"Using {self.unknown_index} for unknown indices."
+            )
+        else:
+            self.re_embed = n_e
+
+        self.sane_index_shape = sane_index_shape
+
+    def remap_to_used(self, inds):
+        ishape = inds.shape
+        assert len(ishape) > 1
+        inds = inds.reshape(ishape[0], -1)
+        used = self.used.to(inds)
+        match = (inds[:, :, None] == used[None, None, ...]).long()
+        new = match.argmax(-1)
+        unknown = match.sum(2) < 1
+        if self.unknown_index == "random":
+            new[unknown] = torch.randint(0, self.re_embed, size=new[unknown].shape).to(device=new.device)
+        else:
+            new[unknown] = self.unknown_index
+        return new.reshape(ishape)
+
+    def unmap_to_all(self, inds):
+        ishape = inds.shape
+        assert len(ishape) > 1
+        inds = inds.reshape(ishape[0], -1)
+        used = self.used.to(inds)
+        if self.re_embed > self.used.shape[0]:  # extra token
+            inds[inds >= self.used.shape[0]] = 0  # simply set to zero
+        back = torch.gather(used[None, :][inds.shape[0] * [0], :], 1, inds)
+        return back.reshape(ishape)
+
+    def forward(self, z):
+        # reshape z -> (batch, height, width, channel) and flatten
+        z = z.permute(0, 2, 3, 1).contiguous()
+        z_flattened = z.view(-1, self.e_dim)
+        # distances from z to embeddings e_j (z - e)^2 = z^2 + e^2 - 2 e * z
+
+        d = (
+            torch.sum(z_flattened**2, dim=1, keepdim=True)
+            + torch.sum(self.embedding.weight**2, dim=1)
+            - 2 * torch.einsum("bd,dn->bn", z_flattened, self.embedding.weight.t())
+        )
+
+        min_encoding_indices = torch.argmin(d, dim=1)
+        z_q = self.embedding(min_encoding_indices).view(z.shape)
+        perplexity = None
+        min_encodings = None
+
+        # compute loss for embedding
+        if not self.legacy:
+            loss = self.beta * torch.mean((z_q.detach() - z) ** 2) + torch.mean((z_q - z.detach()) ** 2)
+        else:
+            loss = torch.mean((z_q.detach() - z) ** 2) + self.beta * torch.mean((z_q - z.detach()) ** 2)
+
+        # preserve gradients
+        z_q = z + (z_q - z).detach()
+
+        # reshape back to match original input shape
+        z_q = z_q.permute(0, 3, 1, 2).contiguous()
+
+        if self.remap is not None:
+            min_encoding_indices = min_encoding_indices.reshape(z.shape[0], -1)  # add batch axis
+            min_encoding_indices = self.remap_to_used(min_encoding_indices)
+            min_encoding_indices = min_encoding_indices.reshape(-1, 1)  # flatten
+
+        if self.sane_index_shape:
+            min_encoding_indices = min_encoding_indices.reshape(z_q.shape[0], z_q.shape[2], z_q.shape[3])
+
+        return z_q, loss, (perplexity, min_encodings, min_encoding_indices)
+
+    def get_codebook_entry(self, indices, shape):
+        # shape specifying (batch, height, width, channel)
+        if self.remap is not None:
+            indices = indices.reshape(shape[0], -1)  # add batch axis
+            indices = self.unmap_to_all(indices)
+            indices = indices.reshape(-1)  # flatten again
+
+        # get quantized latent vectors
+        z_q = self.embedding(indices)
+
+        if shape is not None:
+            z_q = z_q.view(shape)
+            # reshape back to match original input shape
+            z_q = z_q.permute(0, 3, 1, 2).contiguous()
+
+        return z_q
+
+
+class DiagonalGaussianDistribution(object):
+    def __init__(self, parameters, deterministic=False):
+        self.parameters = parameters
+        self.mean, self.logvar = torch.chunk(parameters, 2, dim=1)
+        self.logvar = torch.clamp(self.logvar, -30.0, 20.0)
+        self.deterministic = deterministic
+        self.std = torch.exp(0.5 * self.logvar)
+        self.var = torch.exp(self.logvar)
+        if self.deterministic:
+            self.var = self.std = torch.zeros_like(self.mean).to(device=self.parameters.device)
+
+    def sample(self, generator: Optional[torch.Generator] = None) -> torch.FloatTensor:
+        device = self.parameters.device
+        sample_device = "cpu" if device.type == "mps" else device
+        sample = torch.randn(self.mean.shape, generator=generator, device=sample_device).to(device)
+        x = self.mean + self.std * sample
+        return x
+
+    def kl(self, other=None):
+        if self.deterministic:
+            return torch.Tensor([0.0])
+        else:
+            if other is None:
+                return 0.5 * torch.sum(torch.pow(self.mean, 2) + self.var - 1.0 - self.logvar, dim=[1, 2, 3])
+            else:
+                return 0.5 * torch.sum(
+                    torch.pow(self.mean - other.mean, 2) / other.var
+                    + self.var / other.var
+                    - 1.0
+                    - self.logvar
+                    + other.logvar,
+                    dim=[1, 2, 3],
+                )
+
+    def nll(self, sample, dims=[1, 2, 3]):
+        if self.deterministic:
+            return torch.Tensor([0.0])
+        logtwopi = np.log(2.0 * np.pi)
+        return 0.5 * torch.sum(logtwopi + self.logvar + torch.pow(sample - self.mean, 2) / self.var, dim=dims)
+
+    def mode(self):
+        return self.mean
+
+
+class VQModel(ModelMixin, ConfigMixin):
+    r"""VQ-VAE model from the paper Neural Discrete Representation Learning by Aaron van den Oord, Oriol Vinyals and Koray
+    Kavukcuoglu.
+
+    This model inherits from [`ModelMixin`]. Check the superclass documentation for the generic methods the library
+    implements for all the model (such as downloading or saving, etc.)
+
+    Parameters:
+        in_channels (int, *optional*, defaults to 3): Number of channels in the input image.
+        out_channels (int,  *optional*, defaults to 3): Number of channels in the output.
+        down_block_types (`Tuple[str]`, *optional*, defaults to :
+            obj:`("DownEncoderBlock2D",)`): Tuple of downsample block types.
+        up_block_types (`Tuple[str]`, *optional*, defaults to :
+            obj:`("UpDecoderBlock2D",)`): Tuple of upsample block types.
+        block_out_channels (`Tuple[int]`, *optional*, defaults to :
+            obj:`(64,)`): Tuple of block output channels.
+        act_fn (`str`, *optional*, defaults to `"silu"`): The activation function to use.
+        latent_channels (`int`, *optional*, defaults to `3`): Number of channels in the latent space.
+        sample_size (`int`, *optional*, defaults to `32`): TODO
+        num_vq_embeddings (`int`, *optional*, defaults to `256`): Number of codebook vectors in the VQ-VAE.
+    """
+
+    @register_to_config
+    def __init__(
+        self,
+        in_channels: int = 3,
+        out_channels: int = 3,
+        down_block_types: Tuple[str] = ("DownEncoderBlock2D",),
+        up_block_types: Tuple[str] = ("UpDecoderBlock2D",),
+        block_out_channels: Tuple[int] = (64,),
+        layers_per_block: int = 1,
+        act_fn: str = "silu",
+        latent_channels: int = 3,
+        sample_size: int = 32,
+        num_vq_embeddings: int = 256,
+    ):
+        super().__init__()
+
+        # pass init params to Encoder
+        self.encoder = Encoder(
+            in_channels=in_channels,
+            out_channels=latent_channels,
+            down_block_types=down_block_types,
+            block_out_channels=block_out_channels,
+            layers_per_block=layers_per_block,
+            act_fn=act_fn,
+            double_z=False,
+        )
+
+        self.quant_conv = torch.nn.Conv2d(latent_channels, latent_channels, 1)
+        self.quantize = VectorQuantizer(
+            num_vq_embeddings, latent_channels, beta=0.25, remap=None, sane_index_shape=False
+        )
+        self.post_quant_conv = torch.nn.Conv2d(latent_channels, latent_channels, 1)
+
+        # pass init params to Decoder
+        self.decoder = Decoder(
+            in_channels=latent_channels,
+            out_channels=out_channels,
+            up_block_types=up_block_types,
+            block_out_channels=block_out_channels,
+            layers_per_block=layers_per_block,
+            act_fn=act_fn,
+        )
+
+    def encode(self, x: torch.FloatTensor, return_dict: bool = True) -> VQEncoderOutput:
+        h = self.encoder(x)
+        h = self.quant_conv(h)
+
+        if not return_dict:
+            return (h,)
+
+        return VQEncoderOutput(latents=h)
+
+    def decode(
+        self, h: torch.FloatTensor, force_not_quantize: bool = False, return_dict: bool = True
+    ) -> Union[DecoderOutput, torch.FloatTensor]:
+        # also go through quantization layer
+        if not force_not_quantize:
+            quant, emb_loss, info = self.quantize(h)
+        else:
+            quant = h
+        quant = self.post_quant_conv(quant)
+        dec = self.decoder(quant)
+
+        return dec
+
+        # if not return_dict:
+        #     return (dec,)
+        #
+        # return DecoderOutput(sample=dec)
+
+    def forward(self, sample: torch.FloatTensor, return_dict: bool = True) -> Union[DecoderOutput, torch.FloatTensor]:
+        r"""
+        Args:
+            sample (`torch.FloatTensor`): Input sample.
+            return_dict (`bool`, *optional*, defaults to `True`):
+                Whether or not to return a [`DecoderOutput`] instead of a plain tuple.
+        """
+        x = sample
+        h = self.encode(x).latents
+        dec = self.decode(h).sample
+
+        if not return_dict:
+            return (dec,)
+
+        return DecoderOutput(sample=dec)
+
+
+class AutoencoderKL(ModelMixin, ConfigMixin):
+    r"""Variational Autoencoder (VAE) model with KL loss from the paper Auto-Encoding Variational Bayes by Diederik P. Kingma
+    and Max Welling.
+
+    This model inherits from [`ModelMixin`]. Check the superclass documentation for the generic methods the library
+    implements for all the model (such as downloading or saving, etc.)
+
+    Parameters:
+        in_channels (int, *optional*, defaults to 3): Number of channels in the input image.
+        out_channels (int,  *optional*, defaults to 3): Number of channels in the output.
+        down_block_types (`Tuple[str]`, *optional*, defaults to :
+            obj:`("DownEncoderBlock2D",)`): Tuple of downsample block types.
+        up_block_types (`Tuple[str]`, *optional*, defaults to :
+            obj:`("UpDecoderBlock2D",)`): Tuple of upsample block types.
+        block_out_channels (`Tuple[int]`, *optional*, defaults to :
+            obj:`(64,)`): Tuple of block output channels.
+        act_fn (`str`, *optional*, defaults to `"silu"`): The activation function to use.
+        latent_channels (`int`, *optional*, defaults to `4`): Number of channels in the latent space.
+        sample_size (`int`, *optional*, defaults to `32`): TODO
+    """
+
+    @register_to_config
+    def __init__(
+        self,
+        in_channels: int = 3,
+        out_channels: int = 3,
+        down_block_types: Tuple[str] = ("DownEncoderBlock2D",),
+        up_block_types: Tuple[str] = ("UpDecoderBlock2D",),
+        block_out_channels: Tuple[int] = (64,),
+        layers_per_block: int = 1,
+        act_fn: str = "silu",
+        latent_channels: int = 4,
+        sample_size: int = 32,
+    ):
+        super().__init__()
+
+        # pass init params to Encoder
+        self.encoder = Encoder(
+            in_channels=in_channels,
+            out_channels=latent_channels,
+            down_block_types=down_block_types,
+            block_out_channels=block_out_channels,
+            layers_per_block=layers_per_block,
+            act_fn=act_fn,
+            double_z=True,
+        )
+
+        # pass init params to Decoder
+        self.decoder = Decoder(
+            in_channels=latent_channels,
+            out_channels=out_channels,
+            up_block_types=up_block_types,
+            block_out_channels=block_out_channels,
+            layers_per_block=layers_per_block,
+            act_fn=act_fn,
+        )
+
+        self.quant_conv = torch.nn.Conv2d(2 * latent_channels, 2 * latent_channels, 1)
+        self.post_quant_conv = torch.nn.Conv2d(latent_channels, latent_channels, 1)
+
+    def encode(self, x: torch.FloatTensor, return_dict: bool = True) -> AutoencoderKLOutput:
+        h = self.encoder(x)
+        moments = self.quant_conv(h)
+        posterior = DiagonalGaussianDistribution(moments)
+
+        if not return_dict:
+            return (posterior,)
+
+        return AutoencoderKLOutput(latent_dist=posterior)
+
+    def decode(self, z: torch.FloatTensor, return_dict: bool = True) -> Union[DecoderOutput, torch.FloatTensor]:
+        z = self.post_quant_conv(z)
+        dec = self.decoder(z)
+
+        return dec
+        #
+        # if not return_dict:
+        #     return (dec,)
+        #
+        # return DecoderOutput(sample=dec)
+
+    def forward(
+        self, sample: torch.FloatTensor, sample_posterior: bool = False, return_dict: bool = True
+    ) -> Union[DecoderOutput, torch.FloatTensor]:
+        r"""
+        Args:
+            sample (`torch.FloatTensor`): Input sample.
+            sample_posterior (`bool`, *optional*, defaults to `False`):
+                Whether to sample from the posterior.
+            return_dict (`bool`, *optional*, defaults to `True`):
+                Whether or not to return a [`DecoderOutput`] instead of a plain tuple.
+        """
+        x = sample
+        posterior = self.encode(x).latent_dist
+        if sample_posterior:
+            z = posterior.sample()
+        else:
+            z = posterior.mode()
+        dec = self.decode(z).sample
+
+        if not return_dict:
+            return (dec,)
+
+        return DecoderOutput(sample=dec)

diffusers/onnx_utils.py

@@ -0,0 +1,189 @@
+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+# Copyright (c) 2022, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import os
+import shutil
+from pathlib import Path
+from typing import Optional, Union
+
+import numpy as np
+
+from huggingface_hub import hf_hub_download
+
+from .utils import is_onnx_available, logging
+
+
+if is_onnx_available():
+    import onnxruntime as ort
+
+
+ONNX_WEIGHTS_NAME = "model.onnx"
+
+
+logger = logging.get_logger(__name__)
+
+
+class OnnxRuntimeModel:
+    base_model_prefix = "onnx_model"
+
+    def __init__(self, model=None, **kwargs):
+        logger.info("`diffusers.OnnxRuntimeModel` is experimental and might change in the future.")
+        self.model = model
+        self.model_save_dir = kwargs.get("model_save_dir", None)
+        self.latest_model_name = kwargs.get("latest_model_name", "model.onnx")
+
+    def __call__(self, **kwargs):
+        inputs = {k: np.array(v) for k, v in kwargs.items()}
+        return self.model.run(None, inputs)
+
+    @staticmethod
+    def load_model(path: Union[str, Path], provider=None):
+        """
+        Loads an ONNX Inference session with an ExecutionProvider. Default provider is `CPUExecutionProvider`
+
+        Arguments:
+            path (`str` or `Path`):
+                Directory from which to load
+            provider(`str`, *optional*):
+                Onnxruntime execution provider to use for loading the model, defaults to `CPUExecutionProvider`
+        """
+        if provider is None:
+            logger.info("No onnxruntime provider specified, using CPUExecutionProvider")
+            provider = "CPUExecutionProvider"
+
+        return ort.InferenceSession(path, providers=[provider])
+
+    def _save_pretrained(self, save_directory: Union[str, Path], file_name: Optional[str] = None, **kwargs):
+        """
+        Save a model and its configuration file to a directory, so that it can be re-loaded using the
+        [`~optimum.onnxruntime.modeling_ort.ORTModel.from_pretrained`] class method. It will always save the
+        latest_model_name.
+
+        Arguments:
+            save_directory (`str` or `Path`):
+                Directory where to save the model file.
+            file_name(`str`, *optional*):
+                Overwrites the default model file name from `"model.onnx"` to `file_name`. This allows you to save the
+                model with a different name.
+        """
+        model_file_name = file_name if file_name is not None else ONNX_WEIGHTS_NAME
+
+        src_path = self.model_save_dir.joinpath(self.latest_model_name)
+        dst_path = Path(save_directory).joinpath(model_file_name)
+        if not src_path.samefile(dst_path):
+            shutil.copyfile(src_path, dst_path)
+
+    def save_pretrained(
+        self,
+        save_directory: Union[str, os.PathLike],
+        **kwargs,
+    ):
+        """
+        Save a model to a directory, so that it can be re-loaded using the [`~OnnxModel.from_pretrained`] class
+        method.:
+
+        Arguments:
+            save_directory (`str` or `os.PathLike`):
+                Directory to which to save. Will be created if it doesn't exist.
+        """
+        if os.path.isfile(save_directory):
+            logger.error(f"Provided path ({save_directory}) should be a directory, not a file")
+            return
+
+        os.makedirs(save_directory, exist_ok=True)
+
+        # saving model weights/files
+        self._save_pretrained(save_directory, **kwargs)
+
+    @classmethod
+    def _from_pretrained(
+        cls,
+        model_id: Union[str, Path],
+        use_auth_token: Optional[Union[bool, str, None]] = None,
+        revision: Optional[Union[str, None]] = None,
+        force_download: bool = False,
+        cache_dir: Optional[str] = None,
+        file_name: Optional[str] = None,
+        provider: Optional[str] = None,
+        **kwargs,
+    ):
+        """
+        Load a model from a directory or the HF Hub.
+
+        Arguments:
+            model_id (`str` or `Path`):
+                Directory from which to load
+            use_auth_token (`str` or `bool`):
+                Is needed to load models from a private or gated repository
+            revision (`str`):
+                Revision is the specific model version to use. It can be a branch name, a tag name, or a commit id
+            cache_dir (`Union[str, Path]`, *optional*):
+                Path to a directory in which a downloaded pretrained model configuration should be cached if the
+                standard cache should not be used.
+            force_download (`bool`, *optional*, defaults to `False`):
+                Whether or not to force the (re-)download of the model weights and configuration files, overriding the
+                cached versions if they exist.
+            file_name(`str`):
+                Overwrites the default model file name from `"model.onnx"` to `file_name`. This allows you to load
+                different model files from the same repository or directory.
+            provider(`str`):
+                The ONNX runtime provider, e.g. `CPUExecutionProvider` or `CUDAExecutionProvider`.
+            kwargs (`Dict`, *optional*):
+                kwargs will be passed to the model during initialization
+        """
+        model_file_name = file_name if file_name is not None else ONNX_WEIGHTS_NAME
+        # load model from local directory
+        if os.path.isdir(model_id):
+            model = OnnxRuntimeModel.load_model(os.path.join(model_id, model_file_name), provider=provider)
+            kwargs["model_save_dir"] = Path(model_id)
+        # load model from hub
+        else:
+            # download model
+            model_cache_path = hf_hub_download(
+                repo_id=model_id,
+                filename=model_file_name,
+                use_auth_token=use_auth_token,
+                revision=revision,
+                cache_dir=cache_dir,
+                force_download=force_download,
+            )
+            kwargs["model_save_dir"] = Path(model_cache_path).parent
+            kwargs["latest_model_name"] = Path(model_cache_path).name
+            model = OnnxRuntimeModel.load_model(model_cache_path, provider=provider)
+        return cls(model=model, **kwargs)
+
+    @classmethod
+    def from_pretrained(
+        cls,
+        model_id: Union[str, Path],
+        force_download: bool = True,
+        use_auth_token: Optional[str] = None,
+        cache_dir: Optional[str] = None,
+        **model_kwargs,
+    ):
+        revision = None
+        if len(str(model_id).split("@")) == 2:
+            model_id, revision = model_id.split("@")
+
+        return cls._from_pretrained(
+            model_id=model_id,
+            revision=revision,
+            cache_dir=cache_dir,
+            force_download=force_download,
+            use_auth_token=use_auth_token,
+            **model_kwargs,
+        )

diffusers/optimization.py

@@ -0,0 +1,275 @@
+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""PyTorch optimization for diffusion models."""
+
+import math
+from enum import Enum
+from typing import Optional, Union
+
+from torch.optim import Optimizer
+from torch.optim.lr_scheduler import LambdaLR
+
+from .utils import logging
+
+
+logger = logging.get_logger(__name__)
+
+
+class SchedulerType(Enum):
+    LINEAR = "linear"
+    COSINE = "cosine"
+    COSINE_WITH_RESTARTS = "cosine_with_restarts"
+    POLYNOMIAL = "polynomial"
+    CONSTANT = "constant"
+    CONSTANT_WITH_WARMUP = "constant_with_warmup"
+
+
+def get_constant_schedule(optimizer: Optimizer, last_epoch: int = -1):
+    """
+    Create a schedule with a constant learning rate, using the learning rate set in optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+    return LambdaLR(optimizer, lambda _: 1, last_epoch=last_epoch)
+
+
+def get_constant_schedule_with_warmup(optimizer: Optimizer, num_warmup_steps: int, last_epoch: int = -1):
+    """
+    Create a schedule with a constant learning rate preceded by a warmup period during which the learning rate
+    increases linearly between 0 and the initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step: int):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1.0, num_warmup_steps))
+        return 1.0
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch=last_epoch)
+
+
+def get_linear_schedule_with_warmup(optimizer, num_warmup_steps, num_training_steps, last_epoch=-1):
+    """
+    Create a schedule with a learning rate that decreases linearly from the initial lr set in the optimizer to 0, after
+    a warmup period during which it increases linearly from 0 to the initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step: int):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        return max(
+            0.0, float(num_training_steps - current_step) / float(max(1, num_training_steps - num_warmup_steps))
+        )
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+def get_cosine_schedule_with_warmup(
+    optimizer: Optimizer, num_warmup_steps: int, num_training_steps: int, num_cycles: float = 0.5, last_epoch: int = -1
+):
+    """
+    Create a schedule with a learning rate that decreases following the values of the cosine function between the
+    initial lr set in the optimizer to 0, after a warmup period during which it increases linearly between 0 and the
+    initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        num_cycles (`float`, *optional*, defaults to 0.5):
+            The number of waves in the cosine schedule (the defaults is to just decrease from the max value to 0
+            following a half-cosine).
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        progress = float(current_step - num_warmup_steps) / float(max(1, num_training_steps - num_warmup_steps))
+        return max(0.0, 0.5 * (1.0 + math.cos(math.pi * float(num_cycles) * 2.0 * progress)))
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+def get_cosine_with_hard_restarts_schedule_with_warmup(
+    optimizer: Optimizer, num_warmup_steps: int, num_training_steps: int, num_cycles: int = 1, last_epoch: int = -1
+):
+    """
+    Create a schedule with a learning rate that decreases following the values of the cosine function between the
+    initial lr set in the optimizer to 0, with several hard restarts, after a warmup period during which it increases
+    linearly between 0 and the initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        num_cycles (`int`, *optional*, defaults to 1):
+            The number of hard restarts to use.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        progress = float(current_step - num_warmup_steps) / float(max(1, num_training_steps - num_warmup_steps))
+        if progress >= 1.0:
+            return 0.0
+        return max(0.0, 0.5 * (1.0 + math.cos(math.pi * ((float(num_cycles) * progress) % 1.0))))
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+def get_polynomial_decay_schedule_with_warmup(
+    optimizer, num_warmup_steps, num_training_steps, lr_end=1e-7, power=1.0, last_epoch=-1
+):
+    """
+    Create a schedule with a learning rate that decreases as a polynomial decay from the initial lr set in the
+    optimizer to end lr defined by *lr_end*, after a warmup period during which it increases linearly from 0 to the
+    initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        lr_end (`float`, *optional*, defaults to 1e-7):
+            The end LR.
+        power (`float`, *optional*, defaults to 1.0):
+            Power factor.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Note: *power* defaults to 1.0 as in the fairseq implementation, which in turn is based on the original BERT
+    implementation at
+    https://github.com/google-research/bert/blob/f39e881b169b9d53bea03d2d341b31707a6c052b/optimization.py#L37
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+
+    """
+
+    lr_init = optimizer.defaults["lr"]
+    if not (lr_init > lr_end):
+        raise ValueError(f"lr_end ({lr_end}) must be be smaller than initial lr ({lr_init})")
+
+    def lr_lambda(current_step: int):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        elif current_step > num_training_steps:
+            return lr_end / lr_init  # as LambdaLR multiplies by lr_init
+        else:
+            lr_range = lr_init - lr_end
+            decay_steps = num_training_steps - num_warmup_steps
+            pct_remaining = 1 - (current_step - num_warmup_steps) / decay_steps
+            decay = lr_range * pct_remaining**power + lr_end
+            return decay / lr_init  # as LambdaLR multiplies by lr_init
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+TYPE_TO_SCHEDULER_FUNCTION = {
+    SchedulerType.LINEAR: get_linear_schedule_with_warmup,
+    SchedulerType.COSINE: get_cosine_schedule_with_warmup,
+    SchedulerType.COSINE_WITH_RESTARTS: get_cosine_with_hard_restarts_schedule_with_warmup,
+    SchedulerType.POLYNOMIAL: get_polynomial_decay_schedule_with_warmup,
+    SchedulerType.CONSTANT: get_constant_schedule,
+    SchedulerType.CONSTANT_WITH_WARMUP: get_constant_schedule_with_warmup,
+}
+
+
+def get_scheduler(
+    name: Union[str, SchedulerType],
+    optimizer: Optimizer,
+    num_warmup_steps: Optional[int] = None,
+    num_training_steps: Optional[int] = None,
+):
+    """
+    Unified API to get any scheduler from its name.
+
+    Args:
+        name (`str` or `SchedulerType`):
+            The name of the scheduler to use.
+        optimizer (`torch.optim.Optimizer`):
+            The optimizer that will be used during training.
+        num_warmup_steps (`int`, *optional*):
+            The number of warmup steps to do. This is not required by all schedulers (hence the argument being
+            optional), the function will raise an error if it's unset and the scheduler type requires it.
+        num_training_steps (`int``, *optional*):
+            The number of training steps to do. This is not required by all schedulers (hence the argument being
+            optional), the function will raise an error if it's unset and the scheduler type requires it.
+    """
+    name = SchedulerType(name)
+    schedule_func = TYPE_TO_SCHEDULER_FUNCTION[name]
+    if name == SchedulerType.CONSTANT:
+        return schedule_func(optimizer)
+
+    # All other schedulers require `num_warmup_steps`
+    if num_warmup_steps is None:
+        raise ValueError(f"{name} requires `num_warmup_steps`, please provide that argument.")
+
+    if name == SchedulerType.CONSTANT_WITH_WARMUP:
+        return schedule_func(optimizer, num_warmup_steps=num_warmup_steps)
+
+    # All other schedulers require `num_training_steps`
+    if num_training_steps is None:
+        raise ValueError(f"{name} requires `num_training_steps`, please provide that argument.")
+
+    return schedule_func(optimizer, num_warmup_steps=num_warmup_steps, num_training_steps=num_training_steps)

diffusers/pipeline_utils.py

@@ -0,0 +1,417 @@
+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+# Copyright (c) 2022, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import importlib
+import inspect
+import os
+from dataclasses import dataclass
+from typing import List, Optional, Union
+
+import numpy as np
+import torch
+
+import diffusers
+import PIL
+from huggingface_hub import snapshot_download
+from PIL import Image
+from tqdm.auto import tqdm
+
+from .configuration_utils import ConfigMixin
+from .utils import DIFFUSERS_CACHE, BaseOutput, logging
+
+
+INDEX_FILE = "diffusion_pytorch_model.bin"
+
+
+logger = logging.get_logger(__name__)
+
+
+LOADABLE_CLASSES = {
+    "diffusers": {
+        "ModelMixin": ["save_pretrained", "from_pretrained"],
+        "SchedulerMixin": ["save_config", "from_config"],
+        "DiffusionPipeline": ["save_pretrained", "from_pretrained"],
+        "OnnxRuntimeModel": ["save_pretrained", "from_pretrained"],
+    },
+    "transformers": {
+        "PreTrainedTokenizer": ["save_pretrained", "from_pretrained"],
+        "PreTrainedTokenizerFast": ["save_pretrained", "from_pretrained"],
+        "PreTrainedModel": ["save_pretrained", "from_pretrained"],
+        "FeatureExtractionMixin": ["save_pretrained", "from_pretrained"],
+    },
+}
+
+ALL_IMPORTABLE_CLASSES = {}
+for library in LOADABLE_CLASSES:
+    ALL_IMPORTABLE_CLASSES.update(LOADABLE_CLASSES[library])
+
+
+@dataclass
+class ImagePipelineOutput(BaseOutput):
+    """
+    Output class for image pipelines.
+
+    Args:
+        images (`List[PIL.Image.Image]` or `np.ndarray`)
+            List of denoised PIL images of length `batch_size` or numpy array of shape `(batch_size, height, width,
+            num_channels)`. PIL images or numpy array present the denoised images of the diffusion pipeline.
+    """
+
+    images: Union[List[PIL.Image.Image], np.ndarray]
+
+
+class DiffusionPipeline(ConfigMixin):
+    r"""
+    Base class for all models.
+
+    [`DiffusionPipeline`] takes care of storing all components (models, schedulers, processors) for diffusion pipelines
+    and handles methods for loading, downloading and saving models as well as a few methods common to all pipelines to:
+
+        - move all PyTorch modules to the device of your choice
+        - enabling/disabling the progress bar for the denoising iteration
+
+    Class attributes:
+
+        - **config_name** ([`str`]) -- name of the config file that will store the class and module names of all
+          compenents of the diffusion pipeline.
+    """
+    config_name = "model_index.json"
+
+    def register_modules(self, **kwargs):
+        # import it here to avoid circular import
+        from diffusers import pipelines
+
+        for name, module in kwargs.items():
+            # retrive library
+            library = module.__module__.split(".")[0]
+
+            # check if the module is a pipeline module
+            pipeline_dir = module.__module__.split(".")[-2]
+            path = module.__module__.split(".")
+            is_pipeline_module = pipeline_dir in path and hasattr(pipelines, pipeline_dir)
+
+            # if library is not in LOADABLE_CLASSES, then it is a custom module.
+            # Or if it's a pipeline module, then the module is inside the pipeline
+            # folder so we set the library to module name.
+            if library not in LOADABLE_CLASSES or is_pipeline_module:
+                library = pipeline_dir
+
+            # retrive class_name
+            class_name = module.__class__.__name__
+
+            register_dict = {name: (library, class_name)}
+
+            # save model index config
+            self.register_to_config(**register_dict)
+
+            # set models
+            setattr(self, name, module)
+
+    def save_pretrained(self, save_directory: Union[str, os.PathLike]):
+        """
+        Save all variables of the pipeline that can be saved and loaded as well as the pipelines configuration file to
+        a directory. A pipeline variable can be saved and loaded if its class implements both a save and loading
+        method. The pipeline can easily be re-loaded using the `[`~DiffusionPipeline.from_pretrained`]` class method.
+
+        Arguments:
+            save_directory (`str` or `os.PathLike`):
+                Directory to which to save. Will be created if it doesn't exist.
+        """
+        self.save_config(save_directory)
+
+        model_index_dict = dict(self.config)
+        model_index_dict.pop("_class_name")
+        model_index_dict.pop("_diffusers_version")
+        model_index_dict.pop("_module", None)
+
+        for pipeline_component_name in model_index_dict.keys():
+            sub_model = getattr(self, pipeline_component_name)
+            model_cls = sub_model.__class__
+
+            save_method_name = None
+            # search for the model's base class in LOADABLE_CLASSES
+            for library_name, library_classes in LOADABLE_CLASSES.items():
+                library = importlib.import_module(library_name)
+                for base_class, save_load_methods in library_classes.items():
+                    class_candidate = getattr(library, base_class)
+                    if issubclass(model_cls, class_candidate):
+                        # if we found a suitable base class in LOADABLE_CLASSES then grab its save method
+                        save_method_name = save_load_methods[0]
+                        break
+                if save_method_name is not None:
+                    break
+
+            save_method = getattr(sub_model, save_method_name)
+            save_method(os.path.join(save_directory, pipeline_component_name))
+
+    def to(self, torch_device: Optional[Union[str, torch.device]] = None):
+        if torch_device is None:
+            return self
+
+        module_names, _ = self.extract_init_dict(dict(self.config))
+        for name in module_names.keys():
+            module = getattr(self, name)
+            if isinstance(module, torch.nn.Module):
+                module.to(torch_device)
+        return self
+
+    @property
+    def device(self) -> torch.device:
+        r"""
+        Returns:
+            `torch.device`: The torch device on which the pipeline is located.
+        """
+        module_names, _ = self.extract_init_dict(dict(self.config))
+        for name in module_names.keys():
+            module = getattr(self, name)
+            if isinstance(module, torch.nn.Module):
+                return module.device
+        return torch.device("cpu")
+
+    @classmethod
+    def from_pretrained(cls, pretrained_model_name_or_path: Optional[Union[str, os.PathLike]], **kwargs):
+        r"""
+        Instantiate a PyTorch diffusion pipeline from pre-trained pipeline weights.
+
+        The pipeline is set in evaluation mode by default using `model.eval()` (Dropout modules are deactivated).
+
+        The warning *Weights from XXX not initialized from pretrained model* means that the weights of XXX do not come
+        pretrained with the rest of the model. It is up to you to train those weights with a downstream fine-tuning
+        task.
+
+        The warning *Weights from XXX not used in YYY* means that the layer XXX is not used by YYY, therefore those
+        weights are discarded.
+
+        Parameters:
+            pretrained_model_name_or_path (`str` or `os.PathLike`, *optional*):
+                Can be either:
+
+                    - A string, the *repo id* of a pretrained pipeline hosted inside a model repo on
+                      https://huggingface.co/ Valid repo ids have to be located under a user or organization name, like
+                      `CompVis/ldm-text2im-large-256`.
+                    - A path to a *directory* containing pipeline weights saved using
+                      [`~DiffusionPipeline.save_pretrained`], e.g., `./my_pipeline_directory/`.
+            torch_dtype (`str` or `torch.dtype`, *optional*):
+                Override the default `torch.dtype` and load the model under this dtype. If `"auto"` is passed the dtype
+                will be automatically derived from the model's weights.
+            force_download (`bool`, *optional*, defaults to `False`):
+                Whether or not to force the (re-)download of the model weights and configuration files, overriding the
+                cached versions if they exist.
+            resume_download (`bool`, *optional*, defaults to `False`):
+                Whether or not to delete incompletely received files. Will attempt to resume the download if such a
+                file exists.
+            proxies (`Dict[str, str]`, *optional*):
+                A dictionary of proxy servers to use by protocol or endpoint, e.g., `{'http': 'foo.bar:3128',
+                'http://hostname': 'foo.bar:4012'}`. The proxies are used on each request.
+            output_loading_info(`bool`, *optional*, defaults to `False`):
+                Whether ot not to also return a dictionary containing missing keys, unexpected keys and error messages.
+            local_files_only(`bool`, *optional*, defaults to `False`):
+                Whether or not to only look at local files (i.e., do not try to download the model).
+            use_auth_token (`str` or *bool*, *optional*):
+                The token to use as HTTP bearer authorization for remote files. If `True`, will use the token generated
+                when running `huggingface-cli login` (stored in `~/.huggingface`).
+            revision (`str`, *optional*, defaults to `"main"`):
+                The specific model version to use. It can be a branch name, a tag name, or a commit id, since we use a
+                git-based system for storing models and other artifacts on huggingface.co, so `revision` can be any
+                identifier allowed by git.
+            mirror (`str`, *optional*):
+                Mirror source to accelerate downloads in China. If you are from China and have an accessibility
+                problem, you can set this option to resolve it. Note that we do not guarantee the timeliness or safety.
+                Please refer to the mirror site for more information. specify the folder name here.
+
+            kwargs (remaining dictionary of keyword arguments, *optional*):
+                Can be used to overwrite load - and saveable variables - *i.e.* the pipeline components - of the
+                speficic pipeline class. The overritten components are then directly passed to the pipelines `__init__`
+                method. See example below for more information.
+
+        <Tip>
+
+        Passing `use_auth_token=True`` is required when you want to use a private model, *e.g.*
+        `"CompVis/stable-diffusion-v1-4"`
+
+        </Tip>
+
+        <Tip>
+
+        Activate the special ["offline-mode"](https://huggingface.co/diffusers/installation.html#offline-mode) to use
+        this method in a firewalled environment.
+
+        </Tip>
+
+        Examples:
+
+        ```py
+        >>> from diffusers import DiffusionPipeline
+
+        >>> # Download pipeline from huggingface.co and cache.
+        >>> pipeline = DiffusionPipeline.from_pretrained("CompVis/ldm-text2im-large-256")
+
+        >>> # Download pipeline that requires an authorization token
+        >>> # For more information on access tokens, please refer to this section
+        >>> # of the documentation](https://huggingface.co/docs/hub/security-tokens)
+        >>> pipeline = DiffusionPipeline.from_pretrained("CompVis/stable-diffusion-v1-4", use_auth_token=True)
+
+        >>> # Download pipeline, but overwrite scheduler
+        >>> from diffusers import LMSDiscreteScheduler
+
+        >>> scheduler = LMSDiscreteScheduler(beta_start=0.00085, beta_end=0.012, beta_schedule="scaled_linear")
+        >>> pipeline = DiffusionPipeline.from_pretrained(
+        ...     "CompVis/stable-diffusion-v1-4", scheduler=scheduler, use_auth_token=True
+        ... )
+        ```
+        """
+        cache_dir = kwargs.pop("cache_dir", DIFFUSERS_CACHE)
+        resume_download = kwargs.pop("resume_download", False)
+        proxies = kwargs.pop("proxies", None)
+        local_files_only = kwargs.pop("local_files_only", False)
+        use_auth_token = kwargs.pop("use_auth_token", None)
+        revision = kwargs.pop("revision", None)
+        torch_dtype = kwargs.pop("torch_dtype", None)
+        provider = kwargs.pop("provider", None)
+
+        # 1. Download the checkpoints and configs
+        # use snapshot download here to get it working from from_pretrained
+        if not os.path.isdir(pretrained_model_name_or_path):
+            cached_folder = snapshot_download(
+                pretrained_model_name_or_path,
+                cache_dir=cache_dir,
+                resume_download=resume_download,
+                proxies=proxies,
+                local_files_only=local_files_only,
+                use_auth_token=use_auth_token,
+                revision=revision,
+            )
+        else:
+            cached_folder = pretrained_model_name_or_path
+
+        config_dict = cls.get_config_dict(cached_folder)
+
+        # 2. Load the pipeline class, if using custom module then load it from the hub
+        # if we load from explicit class, let's use it
+        if cls != DiffusionPipeline:
+            pipeline_class = cls
+        else:
+            diffusers_module = importlib.import_module(cls.__module__.split(".")[0])
+            pipeline_class = getattr(diffusers_module, config_dict["_class_name"])
+
+        # some modules can be passed directly to the init
+        # in this case they are already instantiated in `kwargs`
+        # extract them here
+        expected_modules = set(inspect.signature(pipeline_class.__init__).parameters.keys())
+        passed_class_obj = {k: kwargs.pop(k) for k in expected_modules if k in kwargs}
+
+        init_dict, _ = pipeline_class.extract_init_dict(config_dict, **kwargs)
+
+        init_kwargs = {}
+
+        # import it here to avoid circular import
+        from diffusers import pipelines
+
+        # 3. Load each module in the pipeline
+        for name, (library_name, class_name) in init_dict.items():
+            is_pipeline_module = hasattr(pipelines, library_name)
+            loaded_sub_model = None
+
+            # if the model is in a pipeline module, then we load it from the pipeline
+            if name in passed_class_obj:
+                # 1. check that passed_class_obj has correct parent class
+                if not is_pipeline_module:
+                    library = importlib.import_module(library_name)
+                    class_obj = getattr(library, class_name)
+                    importable_classes = LOADABLE_CLASSES[library_name]
+                    class_candidates = {c: getattr(library, c) for c in importable_classes.keys()}
+
+                    expected_class_obj = None
+                    for class_name, class_candidate in class_candidates.items():
+                        if issubclass(class_obj, class_candidate):
+                            expected_class_obj = class_candidate
+
+                    if not issubclass(passed_class_obj[name].__class__, expected_class_obj):
+                        raise ValueError(
+                            f"{passed_class_obj[name]} is of type: {type(passed_class_obj[name])}, but should be"
+                            f" {expected_class_obj}"
+                        )
+                else:
+                    logger.warn(
+                        f"You have passed a non-standard module {passed_class_obj[name]}. We cannot verify whether it"
+                        " has the correct type"
+                    )
+
+                # set passed class object
+                loaded_sub_model = passed_class_obj[name]
+            elif is_pipeline_module:
+                pipeline_module = getattr(pipelines, library_name)
+                class_obj = getattr(pipeline_module, class_name)
+                importable_classes = ALL_IMPORTABLE_CLASSES
+                class_candidates = {c: class_obj for c in importable_classes.keys()}
+            else:
+                # else we just import it from the library.
+                library = importlib.import_module(library_name)
+                class_obj = getattr(library, class_name)
+                importable_classes = LOADABLE_CLASSES[library_name]
+                class_candidates = {c: getattr(library, c) for c in importable_classes.keys()}
+
+            if loaded_sub_model is None:
+                load_method_name = None
+                for class_name, class_candidate in class_candidates.items():
+                    if issubclass(class_obj, class_candidate):
+                        load_method_name = importable_classes[class_name][1]
+
+                load_method = getattr(class_obj, load_method_name)
+
+                loading_kwargs = {}
+                if issubclass(class_obj, torch.nn.Module):
+                    loading_kwargs["torch_dtype"] = torch_dtype
+                if issubclass(class_obj, diffusers.OnnxRuntimeModel):
+                    loading_kwargs["provider"] = provider
+
+                # check if the module is in a subdirectory
+                if os.path.isdir(os.path.join(cached_folder, name)):
+                    loaded_sub_model = load_method(os.path.join(cached_folder, name), **loading_kwargs)
+                else:
+                    # else load from the root directory
+                    loaded_sub_model = load_method(cached_folder, **loading_kwargs)
+
+            init_kwargs[name] = loaded_sub_model  # UNet(...), # DiffusionSchedule(...)
+
+        # 4. Instantiate the pipeline
+        model = pipeline_class(**init_kwargs)
+        return model
+
+    @staticmethod
+    def numpy_to_pil(images):
+        """
+        Convert a numpy image or a batch of images to a PIL image.
+        """
+        if images.ndim == 3:
+            images = images[None, ...]
+        images = (images * 255).round().astype("uint8")
+        pil_images = [Image.fromarray(image) for image in images]
+
+        return pil_images
+
+    def progress_bar(self, iterable):
+        if not hasattr(self, "_progress_bar_config"):
+            self._progress_bar_config = {}
+        elif not isinstance(self._progress_bar_config, dict):
+            raise ValueError(
+                f"`self._progress_bar_config` should be of type `dict`, but is {type(self._progress_bar_config)}."
+            )
+
+        return tqdm(iterable, **self._progress_bar_config)
+
+    def set_progress_bar_config(self, **kwargs):
+        self._progress_bar_config = kwargs

diffusers/pipelines/__init__.py

@@ -0,0 +1,19 @@
+from ..utils import is_onnx_available, is_transformers_available
+from .ddim import DDIMPipeline
+from .ddpm import DDPMPipeline
+from .latent_diffusion_uncond import LDMPipeline
+from .pndm import PNDMPipeline
+from .score_sde_ve import ScoreSdeVePipeline
+from .stochastic_karras_ve import KarrasVePipeline
+
+
+if is_transformers_available():
+    from .latent_diffusion import LDMTextToImagePipeline
+    from .stable_diffusion import (
+        StableDiffusionImg2ImgPipeline,
+        StableDiffusionInpaintPipeline,
+        StableDiffusionPipeline,
+    )
+
+if is_transformers_available() and is_onnx_available():
+    from .stable_diffusion import StableDiffusionOnnxPipeline

diffusers/pipelines/ddim/__init__.py

@@ -0,0 +1,2 @@
+# flake8: noqa
+from .pipeline_ddim import DDIMPipeline