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from typing import Callable, List, Optional, Union |
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import numpy as np |
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import torch |
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from diffusers.pipelines.stable_diffusion import StableDiffusionPipelineOutput |
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from diffusers.models.cross_attention import CrossAttention |
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from diffusers.pipelines.stable_diffusion import StableDiffusionPipeline |
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import matplotlib.pyplot as plt |
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from prompt2prompt.ptp_utils import AttentionStore |
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import prompt2prompt.ptp_utils as ptp_utils |
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from PIL import Image |
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class Prompt2PromptPipeline(StableDiffusionPipeline): |
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r""" |
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Pipeline for text-to-image generation using Stable Diffusion. |
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This model inherits from [`DiffusionPipeline`]. Check the superclass documentation for the generic methods the |
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library implements for all the pipelines (such as downloading or saving, running on a particular device, etc.) |
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Args: |
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vae ([`AutoencoderKL`]): |
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Variational Auto-Encoder (VAE) Model to encode and decode images to and from latent representations. |
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text_encoder ([`CLIPTextModel`]): |
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Frozen text-encoder. Stable Diffusion uses the text portion of |
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[CLIP](https://huggingface.co/docs/transformers/model_doc/clip#transformers.CLIPTextModel), specifically |
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the [clip-vit-large-patch14](https://huggingface.co/openai/clip-vit-large-patch14) variant. |
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tokenizer (`CLIPTokenizer`): |
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Tokenizer of class |
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[CLIPTokenizer](https://huggingface.co/docs/transformers/v4.21.0/en/model_doc/clip#transformers.CLIPTokenizer). |
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unet ([`UNet2DConditionModel`]): Conditional U-Net architecture to denoise the encoded image latents. |
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scheduler ([`SchedulerMixin`]): |
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A scheduler to be used in combination with `unet` to denoise the encoded image latents. Can be one of |
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[`DDIMScheduler`], [`LMSDiscreteScheduler`], or [`PNDMScheduler`]. |
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safety_checker ([`StableDiffusionSafetyChecker`]): |
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Classification module that estimates whether generated images could be considered offensive or harmful. |
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Please, refer to the [model card](https://huggingface.co/runwayml/stable-diffusion-v1-5) for details. |
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feature_extractor ([`CLIPFeatureExtractor`]): |
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Model that extracts features from generated images to be used as inputs for the `safety_checker`. |
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""" |
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_optional_components = ["safety_checker", "feature_extractor"] |
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@torch.no_grad() |
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def __call__( |
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self, |
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prompt: Union[str, List[str]], |
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height: Optional[int] = None, |
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width: Optional[int] = None, |
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controller: AttentionStore = None, |
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num_inference_steps: int = 50, |
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guidance_scale: float = 7.5, |
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negative_prompt: Optional[Union[str, List[str]]] = None, |
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num_images_per_prompt: Optional[int] = 1, |
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eta: float = 0.0, |
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generator: Optional[Union[torch.Generator, List[torch.Generator]]] = None, |
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latents: Optional[torch.FloatTensor] = None, |
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output_type: Optional[str] = "pil", |
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return_dict: bool = True, |
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callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None, |
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callback_steps: Optional[int] = 1, |
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): |
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r""" |
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Function invoked when calling the pipeline for generation. |
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Args: |
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prompt (`str` or `List[str]`): |
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The prompt or prompts to guide the image generation. |
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height (`int`, *optional*, defaults to self.unet.config.sample_size * self.vae_scale_factor): |
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The height in pixels of the generated image. |
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width (`int`, *optional*, defaults to self.unet.config.sample_size * self.vae_scale_factor): |
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The width in pixels of the generated image. |
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num_inference_steps (`int`, *optional*, defaults to 50): |
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The number of denoising steps. More denoising steps usually lead to a higher quality image at the |
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expense of slower inference. |
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guidance_scale (`float`, *optional*, defaults to 7.5): |
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Guidance scale as defined in [Classifier-Free Diffusion Guidance](https://arxiv.org/abs/2207.12598). |
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`guidance_scale` is defined as `w` of equation 2. of [Imagen |
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Paper](https://arxiv.org/pdf/2205.11487.pdf). Guidance scale is enabled by setting `guidance_scale > |
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1`. Higher guidance scale encourages to generate images that are closely linked to the text `prompt`, |
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usually at the expense of lower image quality. |
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negative_prompt (`str` or `List[str]`, *optional*): |
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The prompt or prompts not to guide the image generation. Ignored when not using guidance (i.e., ignored |
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if `guidance_scale` is less than `1`). |
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num_images_per_prompt (`int`, *optional*, defaults to 1): |
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The number of images to generate per prompt. |
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eta (`float`, *optional*, defaults to 0.0): |
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Corresponds to parameter eta (η) in the DDIM paper: https://arxiv.org/abs/2010.02502. Only applies to |
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[`schedulers.DDIMScheduler`], will be ignored for others. |
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generator (`torch.Generator`, *optional*): |
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One or a list of [torch generator(s)](https://pytorch.org/docs/stable/generated/torch.Generator.html) |
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to make generation deterministic. |
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latents (`torch.FloatTensor`, *optional*): |
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Pre-generated noisy latents, sampled from a Gaussian distribution, to be used as inputs for image |
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generation. Can be used to tweak the same generation with different prompts. If not provided, a latents |
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tensor will ge generated by sampling using the supplied random `generator`. |
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output_type (`str`, *optional*, defaults to `"pil"`): |
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The output format of the generate image. Choose between |
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[PIL](https://pillow.readthedocs.io/en/stable/): `PIL.Image.Image` or `np.array`. |
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return_dict (`bool`, *optional*, defaults to `True`): |
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Whether or not to return a [`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] instead of a |
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plain tuple. |
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callback (`Callable`, *optional*): |
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A function that will be called every `callback_steps` steps during inference. The function will be |
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called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`. |
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callback_steps (`int`, *optional*, defaults to 1): |
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The frequency at which the `callback` function will be called. If not specified, the callback will be |
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called at every step. |
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Returns: |
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[`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] or `tuple`: |
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[`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] if `return_dict` is True, otherwise a `tuple. |
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When returning a tuple, the first element is a list with the generated images, and the second element is a |
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list of `bool`s denoting whether the corresponding generated image likely represents "not-safe-for-work" |
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(nsfw) content, according to the `safety_checker`. |
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""" |
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self.register_attention_control(controller) |
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height = height or self.unet.config.sample_size * self.vae_scale_factor |
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width = width or self.unet.config.sample_size * self.vae_scale_factor |
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self.check_inputs(prompt, height, width, callback_steps) |
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batch_size = 1 if isinstance(prompt, str) else len(prompt) |
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device = self._execution_device |
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do_classifier_free_guidance = guidance_scale > 1.0 |
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text_embeddings = self._encode_prompt( |
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prompt, device, num_images_per_prompt, do_classifier_free_guidance, negative_prompt |
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) |
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self.scheduler.set_timesteps(num_inference_steps, device=device) |
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timesteps = self.scheduler.timesteps |
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num_channels_latents = self.unet.in_channels |
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latents = self.prepare_latents( |
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batch_size * num_images_per_prompt, |
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num_channels_latents, |
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height, |
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width, |
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text_embeddings.dtype, |
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device, |
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generator, |
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latents, |
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) |
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extra_step_kwargs = self.prepare_extra_step_kwargs(generator, eta) |
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num_warmup_steps = len(timesteps) - num_inference_steps * self.scheduler.order |
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with self.progress_bar(total=num_inference_steps) as progress_bar: |
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for i, t in enumerate(timesteps): |
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latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents |
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latent_model_input = self.scheduler.scale_model_input(latent_model_input, t) |
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noise_pred = self.unet(latent_model_input, t, encoder_hidden_states=text_embeddings).sample |
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if do_classifier_free_guidance: |
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noise_pred_uncond, noise_pred_text = noise_pred.chunk(2) |
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noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond) |
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latents = self.scheduler.step(noise_pred, t, latents, **extra_step_kwargs).prev_sample |
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latents = controller.step_callback(latents) |
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if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0): |
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progress_bar.update() |
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if callback is not None and i % callback_steps == 0: |
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callback(i, t, latents) |
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image = self.decode_latents(latents) |
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image, has_nsfw_concept = self.run_safety_checker(image, device, text_embeddings.dtype) |
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if output_type == "pil": |
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image = self.numpy_to_pil(image) |
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if not return_dict: |
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return (image, has_nsfw_concept) |
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return StableDiffusionPipelineOutput(images=image, nsfw_content_detected=has_nsfw_concept) |
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def register_attention_control(self, controller): |
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attn_procs = {} |
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cross_att_count = 0 |
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for name in self.unet.attn_processors.keys(): |
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cross_attention_dim = None if name.endswith("attn1.processor") else self.unet.config.cross_attention_dim |
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if name.startswith("mid_block"): |
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hidden_size = self.unet.config.block_out_channels[-1] |
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place_in_unet = "mid" |
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elif name.startswith("up_blocks"): |
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block_id = int(name[len("up_blocks.")]) |
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hidden_size = list(reversed(self.unet.config.block_out_channels))[block_id] |
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place_in_unet = "up" |
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elif name.startswith("down_blocks"): |
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block_id = int(name[len("down_blocks.")]) |
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hidden_size = self.unet.config.block_out_channels[block_id] |
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place_in_unet = "down" |
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else: |
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continue |
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cross_att_count += 1 |
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attn_procs[name] = P2PCrossAttnProcessor( |
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controller=controller, place_in_unet=place_in_unet |
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) |
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self.unet.set_attn_processor(attn_procs) |
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controller.num_att_layers = cross_att_count |
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def aggregate_attention(self, prompts, attention_store: AttentionStore, res: List[int], from_where: List[str], is_cross: bool, select: int): |
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out = [] |
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attention_maps = attention_store.get_average_attention() |
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num_pixels = res[0] * res[1] |
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for location in from_where: |
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for item in attention_maps[f"{location}_{'cross' if is_cross else 'self'}"]: |
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if item.shape[1] == num_pixels: |
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cross_maps = item.reshape(len(prompts), -1, res[0], res[1], item.shape[-1])[select] |
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out.append(cross_maps) |
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out = torch.cat(out, dim=0) |
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out = out.sum(0) / out.shape[0] |
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return out.cpu() |
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def show_cross_attention(self, prompts, attention_store: AttentionStore, res: List[int], from_where: List[str], select: int = 0, image_size: List[int]=[1024, 256], num_rows: int = 1, font_scale=2, thickness=4, cmap_name="plasma"): |
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tokens = self.tokenizer.encode(prompts[select]) |
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decoder = self.tokenizer.decode |
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attention_maps = self.aggregate_attention(prompts, attention_store, res, from_where, True, select) |
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images = [] |
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cmap = plt.get_cmap(cmap_name) |
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cmap_r = cmap.reversed() |
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for i in range(len(tokens)): |
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image = attention_maps[:, :, i] |
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image = 255 * image / image.max() |
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image = image.unsqueeze(-1).expand(*image.shape, 3) |
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image = image.numpy().astype(np.uint8) |
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image = cmap(np.array(image)[:,:,0])[:, :, :3] |
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image = (image - image.min()) / (image.max() - image.min()) |
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image = Image.fromarray(np.uint8(image*255)) |
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image = np.array(image.resize(image_size)) |
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image = ptp_utils.text_under_image(image, decoder(int(tokens[i])), font_scale=font_scale, thickness=thickness) |
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images.append(image) |
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return ptp_utils.view_images(np.stack(images, axis=0), num_rows=num_rows) |
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def show_self_attention_comp(self, prompts, attention_store: AttentionStore, res: int, from_where: List[str], |
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max_com=10, select: int = 0): |
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attention_maps = self.aggregate_attention(prompts, attention_store, res, from_where, False, select).numpy().reshape((res ** 2, res ** 2)) |
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u, s, vh = np.linalg.svd(attention_maps - np.mean(attention_maps, axis=1, keepdims=True)) |
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images = [] |
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for i in range(max_com): |
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image = vh[i].reshape(res, res) |
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image = image - image.min() |
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image = 255 * image / image.max() |
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image = np.repeat(np.expand_dims(image, axis=2), 3, axis=2).astype(np.uint8) |
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image = Image.fromarray(image).resize((256, 256)) |
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image = np.array(image) |
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images.append(image) |
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ptp_utils.view_images(np.concatenate(images, axis=1)) |
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class P2PCrossAttnProcessor: |
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def __init__(self, controller, place_in_unet): |
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super().__init__() |
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self.controller = controller |
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self.place_in_unet = place_in_unet |
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def __call__(self, attn: CrossAttention, hidden_states, encoder_hidden_states=None, attention_mask=None): |
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batch_size, sequence_length, _ = hidden_states.shape |
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attention_mask = attn.prepare_attention_mask(attention_mask, sequence_length, batch_size=batch_size) |
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query = attn.to_q(hidden_states) |
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is_cross = encoder_hidden_states is not None |
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encoder_hidden_states = encoder_hidden_states if encoder_hidden_states is not None else hidden_states |
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key = attn.to_k(encoder_hidden_states) |
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value = attn.to_v(encoder_hidden_states) |
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query = attn.head_to_batch_dim(query) |
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key = attn.head_to_batch_dim(key) |
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value = attn.head_to_batch_dim(value) |
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attention_probs = attn.get_attention_scores(query, key, attention_mask) |
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self.controller(attention_probs, is_cross, self.place_in_unet) |
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hidden_states = torch.bmm(attention_probs, value) |
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hidden_states = attn.batch_to_head_dim(hidden_states) |
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hidden_states = attn.to_out[0](hidden_states) |
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hidden_states = attn.to_out[1](hidden_states) |
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return hidden_states |