[Docs] DiffusionPipeline (#418)

* Start

* up

* up

* finish

docs/source/api/diffusion_pipeline.mdx

@@ -10,19 +10,24 @@ an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express o
 specific language governing permissions and limitations under the License.
 -->
 
-# Models
+# Diffusion Pipeline
 
-Diffusers contains pretrained models for popular algorithms and modules for creating the next set of diffusion models.
-The primary function of these models is to denoise an input sample, by modeling the distribution $p_\theta(\mathbf{x}_{t-1}|\mathbf{x}_t)$.
-The models are built on the base class ['ModelMixin'] that is a `torch.nn.module` with basic functionality for saving and loading models both locally and from the HuggingFace hub.
+The [`DiffusionPipeline`] is the easiest way to load any pretrained diffusion pipeline from the [Hub](https://huggingface.co/models?library=diffusers) and to use it in inference.
 
-## API
+<Tip>
+	
+	One should not use the Diffusion Pipeline class for training or fine-tuning a diffusion model. Individual 
+	components of diffusion pipelines are usually trained individually, so we suggest to directly work 
+	with [`UNetModel`] and [`UNetConditionModel`].
 
-Models should provide the `def forward` function and initialization of the model.
-All saving, loading, and utilities should be in the base ['ModelMixin'] class.
+</Tip>
 
-## Examples
+Any diffusion pipeline that is loaded with [`~DiffusionPipeline.from_pretrained`] will automatically 
+detect the pipeline type, *e.g.* [`StableDiffusionPipeline`] and consequently load each component of the 
+pipeline and pass them into the `__init__` function of the pipeline, *e.g.* [`~StableDiffusionPipeline.__init__`].
 
-- The ['UNetModel'] was proposed in [TODO](https://arxiv.org/) and has been used in paper1, paper2, paper3.
-- Extensions of the ['UNetModel'] include the ['UNetGlideModel'] that uses attention and timestep embeddings for the [GLIDE](https://arxiv.org/abs/2112.10741) paper, the ['UNetGradTTS'] model from this [paper](https://arxiv.org/abs/2105.06337) for text-to-speech, ['UNetLDMModel'] for latent-diffusion models in this [paper](https://arxiv.org/abs/2112.10752), and the ['TemporalUNet'] used for time-series prediciton in this reinforcement learning [paper](https://arxiv.org/abs/2205.09991).
-- TODO: mention VAE / SDE score estimation
\ No newline at end of file
+Any pipeline object can be saved locally with [`~DiffusionPipeline.save_pretrained`].
+
+[[autodoc]] DiffusionPipeline
+	- from_pretrained
+	- save_pretrained

docs/source/api/pipelines/stable_diffusion.mdx

 # Stable diffusion pipelines
 
-## Overview
-
 Stable Diffusion is a text-to-image _latent diffusion_ model created by the researchers and engineers from [CompVis](https://github.com/CompVis), [Stability AI](https://stability.ai/) and [LAION](https://laion.ai/). It's trained on 512x512 images from a subset of the [LAION-5B](https://laion.ai/blog/laion-5b/) dataset. This model uses a frozen CLIP ViT-L/14 text encoder to condition the model on text prompts. With its 860M UNet and 123M text encoder, the model is relatively lightweight and can run on consumer GPUs.
 
 Latent diffusion is the research on top of which Stable Diffusion was built. It was proposed in [High-Resolution Image Synthesis with Latent Diffusion Models](https://arxiv.org/abs/2112.10752) by Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, Björn Ommer. You can learn more details about it in the [specific pipeline for latent diffusion](pipelines/latent_diffusion) that is part of 🤗 Diffusers.
 
 For more details about how Stable Diffusion works and how it differs from the base latent diffusion model, please refer to the official [launch announcement post](https://stability.ai/blog/stable-diffusion-announcement) and [this section of our own blog post](https://huggingface.co/blog/stable_diffusion#how-does-stable-diffusion-work).
 
-## Tips
-
+*Tips*:
 - To tweak your prompts on a specific result you liked, you can generate your own latents, as demonstrated in the following notebook: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/pcuenca/diffusers-examples/blob/main/notebooks/stable-diffusion-seeds.ipynb)
 - TODO: some interesting Tips
 
-## Available pipelines
-
 | Pipeline | Tasks | Colab | Demo
  |---|---|:---:|:---:|
  | [pipeline_stable_diffusion.py](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion.py) | *Text-to-Image Generation* | [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/huggingface/notebooks/blob/main/diffusers/stable_diffusion.ipynb) | [🤗 Stable Diffusion](https://huggingface.co/spaces/stabilityai/stable-diffusion)
  | [pipeline_stable_diffusion_img2img.py](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_img2img.py) | *Image-to-Image Text-Guided Generation* | [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/patil-suraj/Notebooks/blob/master/image_2_image_using_diffusers.ipynb) | [🤗 Diffuse the Rest](https://huggingface.co/spaces/huggingface/diffuse-the-rest)
  | [pipeline_stable_diffusion_inpaint.py](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_inpaint.py) | **Experimental** – *Text-Guided Image Inpainting* | [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/patil-suraj/Notebooks/blob/master/in_painting_with_stable_diffusion_using_diffusers.ipynb) | Coming soon
 
-## API
-
 [[autodoc]] StableDiffusionPipeline
+	 - __init__
      - __call__
      - enable_attention_slicing
      - disable_attention_slicing
 
 [[autodoc]] StableDiffusionImg2ImgPipeline
+	 - __init__
      - __call__
      - enable_attention_slicing
      - disable_attention_slicing
 
 [[autodoc]] StableDiffusionInpaintPipeline
+	 - __init__
      - __call__
      - enable_attention_slicing
      - disable_attention_slicing

docs/source/installation.mdx

@@ -14,7 +14,7 @@ specific language governing permissions and limitations under the License.
 
 Install Diffusers for with PyTorch. Support for other libraries will come in the future
 
-🤗 Diffusers is tested on Python 3.6+, and PyTorch 1.4.0+.
+🤗 Diffusers is tested on Python 3.7+, and PyTorch 1.7.0+.
 
 ## Install with pip
 

src/diffusers/pipeline_utils.py

@@ -72,6 +72,20 @@ class ImagePipelineOutput(BaseOutput):
 
 
 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):
@@ -105,6 +119,15 @@ class DiffusionPipeline(ConfigMixin):
             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)
@@ -145,6 +168,10 @@ class DiffusionPipeline(ConfigMixin):
 
     @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)
@@ -155,7 +182,94 @@ class DiffusionPipeline(ConfigMixin):
     @classmethod
     def from_pretrained(cls, pretrained_model_name_or_path: Optional[Union[str, os.PathLike]], **kwargs):
         r"""
-        Add docstrings
+        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)