import types from typing import List, Optional, Tuple, Union import torch from transformers import CLIPTextModelWithProjection, CLIPTokenizer from transformers.models.clip.modeling_clip import CLIPTextModelOutput from diffusers.models import PriorTransformer from diffusers.pipelines import DiffusionPipeline, StableDiffusionImageVariationPipeline from diffusers.schedulers import UnCLIPScheduler from diffusers.utils import logging, randn_tensor logger = logging.get_logger(__name__) # pylint: disable=invalid-name def _encode_image(self, image, device, num_images_per_prompt, do_classifier_free_guidance): image = image.to(device=device) image_embeddings = image # take image as image_embeddings image_embeddings = image_embeddings.unsqueeze(1) # duplicate image embeddings for each generation per prompt, using mps friendly method bs_embed, seq_len, _ = image_embeddings.shape image_embeddings = image_embeddings.repeat(1, num_images_per_prompt, 1) image_embeddings = image_embeddings.view(bs_embed * num_images_per_prompt, seq_len, -1) if do_classifier_free_guidance: uncond_embeddings = torch.zeros_like(image_embeddings) # For classifier free guidance, we need to do two forward passes. # Here we concatenate the unconditional and text embeddings into a single batch # to avoid doing two forward passes image_embeddings = torch.cat([uncond_embeddings, image_embeddings]) return image_embeddings class StableUnCLIPPipeline(DiffusionPipeline): def __init__( self, prior: PriorTransformer, tokenizer: CLIPTokenizer, text_encoder: CLIPTextModelWithProjection, prior_scheduler: UnCLIPScheduler, decoder_pipe_kwargs: Optional[dict] = None, ): super().__init__() decoder_pipe_kwargs = {"image_encoder": None} if decoder_pipe_kwargs is None else decoder_pipe_kwargs decoder_pipe_kwargs["torch_dtype"] = decoder_pipe_kwargs.get("torch_dtype", None) or prior.dtype self.decoder_pipe = StableDiffusionImageVariationPipeline.from_pretrained( "lambdalabs/sd-image-variations-diffusers", **decoder_pipe_kwargs ) # replace `_encode_image` method self.decoder_pipe._encode_image = types.MethodType(_encode_image, self.decoder_pipe) self.register_modules( prior=prior, tokenizer=tokenizer, text_encoder=text_encoder, prior_scheduler=prior_scheduler, ) def _encode_prompt( self, prompt, device, num_images_per_prompt, do_classifier_free_guidance, text_model_output: Optional[Union[CLIPTextModelOutput, Tuple]] = None, text_attention_mask: Optional[torch.Tensor] = None, ): if text_model_output is None: batch_size = len(prompt) if isinstance(prompt, list) else 1 # get prompt text embeddings text_inputs = self.tokenizer( prompt, padding="max_length", max_length=self.tokenizer.model_max_length, return_tensors="pt", ) text_input_ids = text_inputs.input_ids text_mask = text_inputs.attention_mask.bool().to(device) if text_input_ids.shape[-1] > self.tokenizer.model_max_length: removed_text = self.tokenizer.batch_decode(text_input_ids[:, self.tokenizer.model_max_length :]) logger.warning( "The following part of your input was truncated because CLIP can only handle sequences up to" f" {self.tokenizer.model_max_length} tokens: {removed_text}" ) text_input_ids = text_input_ids[:, : self.tokenizer.model_max_length] text_encoder_output = self.text_encoder(text_input_ids.to(device)) text_embeddings = text_encoder_output.text_embeds text_encoder_hidden_states = text_encoder_output.last_hidden_state else: batch_size = text_model_output[0].shape[0] text_embeddings, text_encoder_hidden_states = text_model_output[0], text_model_output[1] text_mask = text_attention_mask text_embeddings = text_embeddings.repeat_interleave(num_images_per_prompt, dim=0) text_encoder_hidden_states = text_encoder_hidden_states.repeat_interleave(num_images_per_prompt, dim=0) text_mask = text_mask.repeat_interleave(num_images_per_prompt, dim=0) if do_classifier_free_guidance: uncond_tokens = [""] * batch_size uncond_input = self.tokenizer( uncond_tokens, padding="max_length", max_length=self.tokenizer.model_max_length, truncation=True, return_tensors="pt", ) uncond_text_mask = uncond_input.attention_mask.bool().to(device) uncond_embeddings_text_encoder_output = self.text_encoder(uncond_input.input_ids.to(device)) uncond_embeddings = uncond_embeddings_text_encoder_output.text_embeds uncond_text_encoder_hidden_states = uncond_embeddings_text_encoder_output.last_hidden_state # duplicate unconditional embeddings for each generation per prompt, using mps friendly method seq_len = uncond_embeddings.shape[1] uncond_embeddings = uncond_embeddings.repeat(1, num_images_per_prompt) uncond_embeddings = uncond_embeddings.view(batch_size * num_images_per_prompt, seq_len) seq_len = uncond_text_encoder_hidden_states.shape[1] uncond_text_encoder_hidden_states = uncond_text_encoder_hidden_states.repeat(1, num_images_per_prompt, 1) uncond_text_encoder_hidden_states = uncond_text_encoder_hidden_states.view( batch_size * num_images_per_prompt, seq_len, -1 ) uncond_text_mask = uncond_text_mask.repeat_interleave(num_images_per_prompt, dim=0) # done duplicates # For classifier free guidance, we need to do two forward passes. # Here we concatenate the unconditional and text embeddings into a single batch # to avoid doing two forward passes text_embeddings = torch.cat([uncond_embeddings, text_embeddings]) text_encoder_hidden_states = torch.cat([uncond_text_encoder_hidden_states, text_encoder_hidden_states]) text_mask = torch.cat([uncond_text_mask, text_mask]) return text_embeddings, text_encoder_hidden_states, text_mask @property def _execution_device(self): r""" Returns the device on which the pipeline's models will be executed. After calling `pipeline.enable_sequential_cpu_offload()` the execution device can only be inferred from Accelerate's module hooks. """ if self.device != torch.device("meta") or not hasattr(self.prior, "_hf_hook"): return self.device for module in self.prior.modules(): if ( hasattr(module, "_hf_hook") and hasattr(module._hf_hook, "execution_device") and module._hf_hook.execution_device is not None ): return torch.device(module._hf_hook.execution_device) return self.device def prepare_latents(self, shape, dtype, device, generator, latents, scheduler): if latents is None: latents = randn_tensor(shape, generator=generator, device=device, dtype=dtype) else: if latents.shape != shape: raise ValueError(f"Unexpected latents shape, got {latents.shape}, expected {shape}") latents = latents.to(device) latents = latents * scheduler.init_noise_sigma return latents def to(self, torch_device: Optional[Union[str, torch.device]] = None): self.decoder_pipe.to(torch_device) super().to(torch_device) @torch.no_grad() def __call__( self, prompt: Optional[Union[str, List[str]]] = None, height: Optional[int] = None, width: Optional[int] = None, num_images_per_prompt: int = 1, prior_num_inference_steps: int = 25, generator: Optional[torch.Generator] = None, prior_latents: Optional[torch.FloatTensor] = None, text_model_output: Optional[Union[CLIPTextModelOutput, Tuple]] = None, text_attention_mask: Optional[torch.Tensor] = None, prior_guidance_scale: float = 4.0, decoder_guidance_scale: float = 8.0, decoder_num_inference_steps: int = 50, decoder_num_images_per_prompt: Optional[int] = 1, decoder_eta: float = 0.0, output_type: Optional[str] = "pil", return_dict: bool = True, ): if prompt is not None: if isinstance(prompt, str): batch_size = 1 elif isinstance(prompt, list): batch_size = len(prompt) else: raise ValueError(f"`prompt` has to be of type `str` or `list` but is {type(prompt)}") else: batch_size = text_model_output[0].shape[0] device = self._execution_device batch_size = batch_size * num_images_per_prompt do_classifier_free_guidance = prior_guidance_scale > 1.0 or decoder_guidance_scale > 1.0 text_embeddings, text_encoder_hidden_states, text_mask = self._encode_prompt( prompt, device, num_images_per_prompt, do_classifier_free_guidance, text_model_output, text_attention_mask ) # prior self.prior_scheduler.set_timesteps(prior_num_inference_steps, device=device) prior_timesteps_tensor = self.prior_scheduler.timesteps embedding_dim = self.prior.config.embedding_dim prior_latents = self.prepare_latents( (batch_size, embedding_dim), text_embeddings.dtype, device, generator, prior_latents, self.prior_scheduler, ) for i, t in enumerate(self.progress_bar(prior_timesteps_tensor)): # expand the latents if we are doing classifier free guidance latent_model_input = torch.cat([prior_latents] * 2) if do_classifier_free_guidance else prior_latents predicted_image_embedding = self.prior( latent_model_input, timestep=t, proj_embedding=text_embeddings, encoder_hidden_states=text_encoder_hidden_states, attention_mask=text_mask, ).predicted_image_embedding if do_classifier_free_guidance: predicted_image_embedding_uncond, predicted_image_embedding_text = predicted_image_embedding.chunk(2) predicted_image_embedding = predicted_image_embedding_uncond + prior_guidance_scale * ( predicted_image_embedding_text - predicted_image_embedding_uncond ) if i + 1 == prior_timesteps_tensor.shape[0]: prev_timestep = None else: prev_timestep = prior_timesteps_tensor[i + 1] prior_latents = self.prior_scheduler.step( predicted_image_embedding, timestep=t, sample=prior_latents, generator=generator, prev_timestep=prev_timestep, ).prev_sample prior_latents = self.prior.post_process_latents(prior_latents) image_embeddings = prior_latents output = self.decoder_pipe( image=image_embeddings, height=height, width=width, num_inference_steps=decoder_num_inference_steps, guidance_scale=decoder_guidance_scale, generator=generator, output_type=output_type, return_dict=return_dict, num_images_per_prompt=decoder_num_images_per_prompt, eta=decoder_eta, ) return output