[Community Pipelines] EDICT pipeline implementation (#3153)

* EDICT pipeline initial commit

- Starting point taking from https://github.com/Joqsan/edict-diffusion



* refactor __init__() method

* minor refactoring

* refactor scheduler code

- remove scheduler and move its methods to the EDICTPipeline class

* make CFG optional
- refactor encode_prompt().
- include optional generator for sampling with vae.
- minor variable renaming

* add EDICT pipeline description to README.md

* replace preprocess() with VaeImageProcessor

* run make style and make quality commands

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

examples/community/README.md

@@ -32,6 +32,8 @@ MagicMix | Diffusion Pipeline for semantic mixing of an image and a text prompt
 | DDIM Noise Comparative Analysis Pipeline | Investigating how the diffusion models learn visual concepts from each noise level (which is a contribution of [P2 weighting (CVPR 2022)](https://arxiv.org/abs/2204.00227)) | [DDIM Noise Comparative Analysis Pipeline](#ddim-noise-comparative-analysis-pipeline) | - |[Aengus (Duc-Anh)](https://github.com/aengusng8) |
 | CLIP Guided Img2Img Stable Diffusion Pipeline | Doing CLIP guidance for image to image generation with Stable Diffusion | [CLIP Guided Img2Img Stable Diffusion](#clip-guided-img2img-stable-diffusion) | - | [Nipun Jindal](https://github.com/nipunjindal/) | 
 | TensorRT Stable Diffusion Pipeline | Accelerates the Stable Diffusion Text2Image Pipeline using TensorRT | [TensorRT Stable Diffusion Pipeline](#tensorrt-text2image-stable-diffusion-pipeline) | - |[Asfiya Baig](https://github.com/asfiyab-nvidia) |
+| EDICT Image Editing Pipeline | Diffusion pipeline for text-guided image editing | [EDICT Image Editing Pipeline](#edict-image-editing-pipeline) | - | [Joqsan Azocar](https://github.com/Joqsan) | 
+
 
 
 To load a custom pipeline you just need to pass the `custom_pipeline` argument to `DiffusionPipeline`, as one of the files in `diffusers/examples/community`. Feel free to send a PR with your own pipelines, we will merge them quickly.
@@ -1161,3 +1163,87 @@ prompt = "a beautiful photograph of Mt. Fuji during cherry blossom"
 image = pipe(prompt).images[0]
 image.save('tensorrt_mt_fuji.png')
 ```
+
+### EDICT Image Editing Pipeline
+
+This pipeline implements the text-guided image editing approach from the paper [EDICT: Exact Diffusion Inversion via Coupled Transformations](https://arxiv.org/abs/2211.12446). You have to pass:
+- (`PIL`) `image` you want to edit.
+- `base_prompt`: the text prompt describing the current image (before editing).
+- `target_prompt`: the text prompt describing with the edits.
+
+```python
+from diffusers import DiffusionPipeline, DDIMScheduler
+from transformers import CLIPTextModel
+import torch, PIL, requests
+from io import BytesIO
+from IPython.display import display
+
+def center_crop_and_resize(im):
+
+    width, height = im.size
+    d = min(width, height)
+    left = (width - d) / 2
+    upper = (height - d) / 2
+    right = (width + d) / 2
+    lower = (height + d) / 2
+
+    return im.crop((left, upper, right, lower)).resize((512, 512))
+
+torch_dtype = torch.float16
+device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
+
+# scheduler and text_encoder param values as in the paper
+scheduler = DDIMScheduler(
+        num_train_timesteps=1000,
+        beta_start=0.00085,
+        beta_end=0.012,
+        beta_schedule="scaled_linear",
+        set_alpha_to_one=False,
+        clip_sample=False,
+)
+
+text_encoder = CLIPTextModel.from_pretrained(
+    pretrained_model_name_or_path="openai/clip-vit-large-patch14",
+    torch_dtype=torch_dtype,
+)
+
+# initialize pipeline
+pipeline = DiffusionPipeline.from_pretrained(
+    pretrained_model_name_or_path="CompVis/stable-diffusion-v1-4",
+    custom_pipeline="edict_pipeline",
+    revision="fp16",
+    scheduler=scheduler,
+    text_encoder=text_encoder,
+    leapfrog_steps=True,
+    torch_dtype=torch_dtype,
+).to(device)
+
+# download image
+image_url = "https://huggingface.co/datasets/Joqsan/images/resolve/main/imagenet_dog_1.jpeg"
+response = requests.get(image_url)
+image = PIL.Image.open(BytesIO(response.content))
+
+# preprocess it
+cropped_image = center_crop_and_resize(image)
+
+# define the prompts
+base_prompt = "A dog"
+target_prompt = "A golden retriever"
+
+# run the pipeline
+result_image = pipeline(
+      base_prompt=base_prompt, 
+      target_prompt=target_prompt, 
+      image=cropped_image,
+)
+
+display(result_image)
+```
+
+Init Image
+
+![img2img_init_edict_text_editing](https://huggingface.co/datasets/Joqsan/images/resolve/main/imagenet_dog_1.jpeg)
+
+Output Image
+
+![img2img_edict_text_editing](https://huggingface.co/datasets/Joqsan/images/resolve/main/imagenet_dog_1_cropped_generated.png)

examples/community/edict_pipeline.py

+from typing import Optional
+
+import torch
+from PIL import Image
+from tqdm.auto import tqdm
+from transformers import CLIPTextModel, CLIPTokenizer
+
+from diffusers import AutoencoderKL, DDIMScheduler, DiffusionPipeline, UNet2DConditionModel
+from diffusers.image_processor import VaeImageProcessor
+from diffusers.utils import (
+    deprecate,
+)
+
+
+class EDICTPipeline(DiffusionPipeline):
+    def __init__(
+        self,
+        vae: AutoencoderKL,
+        text_encoder: CLIPTextModel,
+        tokenizer: CLIPTokenizer,
+        unet: UNet2DConditionModel,
+        scheduler: DDIMScheduler,
+        mixing_coeff: float = 0.93,
+        leapfrog_steps: bool = True,
+    ):
+        self.mixing_coeff = mixing_coeff
+        self.leapfrog_steps = leapfrog_steps
+
+        super().__init__()
+        self.register_modules(
+            vae=vae,
+            text_encoder=text_encoder,
+            tokenizer=tokenizer,
+            unet=unet,
+            scheduler=scheduler,
+        )
+
+        self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1)
+        self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor)
+
+    def _encode_prompt(
+        self, prompt: str, negative_prompt: Optional[str] = None, do_classifier_free_guidance: bool = False
+    ):
+        text_inputs = self.tokenizer(
+            prompt,
+            padding="max_length",
+            max_length=self.tokenizer.model_max_length,
+            truncation=True,
+            return_tensors="pt",
+        )
+
+        prompt_embeds = self.text_encoder(text_inputs.input_ids.to(self.device)).last_hidden_state
+
+        prompt_embeds = prompt_embeds.to(dtype=self.text_encoder.dtype, device=self.device)
+
+        if do_classifier_free_guidance:
+            uncond_tokens = "" if negative_prompt is None else negative_prompt
+
+            uncond_input = self.tokenizer(
+                uncond_tokens,
+                padding="max_length",
+                max_length=self.tokenizer.model_max_length,
+                truncation=True,
+                return_tensors="pt",
+            )
+
+            negative_prompt_embeds = self.text_encoder(uncond_input.input_ids.to(self.device)).last_hidden_state
+
+            prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds])
+
+        return prompt_embeds
+
+    def denoise_mixing_layer(self, x: torch.Tensor, y: torch.Tensor):
+        x = self.mixing_coeff * x + (1 - self.mixing_coeff) * y
+        y = self.mixing_coeff * y + (1 - self.mixing_coeff) * x
+
+        return [x, y]
+
+    def noise_mixing_layer(self, x: torch.Tensor, y: torch.Tensor):
+        y = (y - (1 - self.mixing_coeff) * x) / self.mixing_coeff
+        x = (x - (1 - self.mixing_coeff) * y) / self.mixing_coeff
+
+        return [x, y]
+
+    def _get_alpha_and_beta(self, t: torch.Tensor):
+        # as self.alphas_cumprod is always in cpu
+        t = int(t)
+
+        alpha_prod = self.scheduler.alphas_cumprod[t] if t >= 0 else self.scheduler.final_alpha_cumprod
+
+        return alpha_prod, 1 - alpha_prod
+
+    def noise_step(
+        self,
+        base: torch.Tensor,
+        model_input: torch.Tensor,
+        model_output: torch.Tensor,
+        timestep: torch.Tensor,
+    ):
+        prev_timestep = timestep - self.scheduler.config.num_train_timesteps / self.scheduler.num_inference_steps
+
+        alpha_prod_t, beta_prod_t = self._get_alpha_and_beta(timestep)
+        alpha_prod_t_prev, beta_prod_t_prev = self._get_alpha_and_beta(prev_timestep)
+
+        a_t = (alpha_prod_t_prev / alpha_prod_t) ** 0.5
+        b_t = -a_t * (beta_prod_t**0.5) + beta_prod_t_prev**0.5
+
+        next_model_input = (base - b_t * model_output) / a_t
+
+        return model_input, next_model_input.to(base.dtype)
+
+    def denoise_step(
+        self,
+        base: torch.Tensor,
+        model_input: torch.Tensor,
+        model_output: torch.Tensor,
+        timestep: torch.Tensor,
+    ):
+        prev_timestep = timestep - self.scheduler.config.num_train_timesteps / self.scheduler.num_inference_steps
+
+        alpha_prod_t, beta_prod_t = self._get_alpha_and_beta(timestep)
+        alpha_prod_t_prev, beta_prod_t_prev = self._get_alpha_and_beta(prev_timestep)
+
+        a_t = (alpha_prod_t_prev / alpha_prod_t) ** 0.5
+        b_t = -a_t * (beta_prod_t**0.5) + beta_prod_t_prev**0.5
+        next_model_input = a_t * base + b_t * model_output
+
+        return model_input, next_model_input.to(base.dtype)
+
+    @torch.no_grad()
+    def decode_latents(self, latents: torch.Tensor):
+        latents = 1 / self.vae.config.scaling_factor * latents
+        image = self.vae.decode(latents).sample
+        image = (image / 2 + 0.5).clamp(0, 1)
+        return image
+
+    @torch.no_grad()
+    def prepare_latents(
+        self,
+        image: Image.Image,
+        text_embeds: torch.Tensor,
+        timesteps: torch.Tensor,
+        guidance_scale: float,
+        generator: Optional[torch.Generator] = None,
+    ):
+        do_classifier_free_guidance = guidance_scale > 1.0
+
+        image = image.to(device=self.device, dtype=text_embeds.dtype)
+        latent = self.vae.encode(image).latent_dist.sample(generator)
+
+        latent = self.vae.config.scaling_factor * latent
+
+        coupled_latents = [latent.clone(), latent.clone()]
+
+        for i, t in tqdm(enumerate(timesteps), total=len(timesteps)):
+            coupled_latents = self.noise_mixing_layer(x=coupled_latents[0], y=coupled_latents[1])
+
+            # j - model_input index, k - base index
+            for j in range(2):
+                k = j ^ 1
+
+                if self.leapfrog_steps:
+                    if i % 2 == 0:
+                        k, j = j, k
+
+                model_input = coupled_latents[j]
+                base = coupled_latents[k]
+
+                latent_model_input = torch.cat([model_input] * 2) if do_classifier_free_guidance else model_input
+
+                noise_pred = self.unet(latent_model_input, t, encoder_hidden_states=text_embeds).sample
+
+                if do_classifier_free_guidance:
+                    noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
+                    noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
+
+                base, model_input = self.noise_step(
+                    base=base,
+                    model_input=model_input,
+                    model_output=noise_pred,
+                    timestep=t,
+                )
+
+                coupled_latents[k] = model_input
+
+        return coupled_latents
+
+    @torch.no_grad()
+    def __call__(
+        self,
+        base_prompt: str,
+        target_prompt: str,
+        image: Image.Image,
+        guidance_scale: float = 3.0,
+        num_inference_steps: int = 50,
+        strength: float = 0.8,
+        negative_prompt: Optional[str] = None,
+        generator: Optional[torch.Generator] = None,
+        output_type: Optional[str] = "pil",
+    ):
+        do_classifier_free_guidance = guidance_scale > 1.0
+
+        image = self.image_processor.preprocess(image)
+
+        base_embeds = self._encode_prompt(base_prompt, negative_prompt, do_classifier_free_guidance)
+        target_embeds = self._encode_prompt(target_prompt, negative_prompt, do_classifier_free_guidance)
+
+        self.scheduler.set_timesteps(num_inference_steps, self.device)
+
+        t_limit = num_inference_steps - int(num_inference_steps * strength)
+        fwd_timesteps = self.scheduler.timesteps[t_limit:]
+        bwd_timesteps = fwd_timesteps.flip(0)
+
+        coupled_latents = self.prepare_latents(image, base_embeds, bwd_timesteps, guidance_scale, generator)
+
+        for i, t in tqdm(enumerate(fwd_timesteps), total=len(fwd_timesteps)):
+            # j - model_input index, k - base index
+            for k in range(2):
+                j = k ^ 1
+
+                if self.leapfrog_steps:
+                    if i % 2 == 1:
+                        k, j = j, k
+
+                model_input = coupled_latents[j]
+                base = coupled_latents[k]
+
+                latent_model_input = torch.cat([model_input] * 2) if do_classifier_free_guidance else model_input
+
+                noise_pred = self.unet(latent_model_input, t, encoder_hidden_states=target_embeds).sample
+
+                if do_classifier_free_guidance:
+                    noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
+                    noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
+
+                base, model_input = self.denoise_step(
+                    base=base,
+                    model_input=model_input,
+                    model_output=noise_pred,
+                    timestep=t,
+                )
+
+                coupled_latents[k] = model_input
+
+            coupled_latents = self.denoise_mixing_layer(x=coupled_latents[0], y=coupled_latents[1])
+
+        # either one is fine
+        final_latent = coupled_latents[0]
+
+        if output_type not in ["latent", "pt", "np", "pil"]:
+            deprecation_message = (
+                f"the output_type {output_type} is outdated. Please make sure to set it to one of these instead: "
+                "`pil`, `np`, `pt`, `latent`"
+            )
+            deprecate("Unsupported output_type", "1.0.0", deprecation_message, standard_warn=False)
+            output_type = "np"
+
+        if output_type == "latent":
+            image = final_latent
+        else:
+            image = self.decode_latents(final_latent)
+            image = self.image_processor.postprocess(image, output_type=output_type)
+
+        return image