116 lines
4.2 KiB
Python
116 lines
4.2 KiB
Python
from logging import getLogger
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from math import ceil
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from typing import List, Optional
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import numpy as np
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from diffusers import OnnxStableDiffusionPipeline
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logger = getLogger(__name__)
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MAX_TOKENS_PER_GROUP = 77
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def expand_prompt(
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self: OnnxStableDiffusionPipeline,
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prompt: str,
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num_images_per_prompt: int,
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do_classifier_free_guidance: bool,
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negative_prompt: Optional[str] = None,
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) -> "np.NDArray":
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# self provides:
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# tokenizer: CLIPTokenizer
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# encoder: OnnxRuntimeModel
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batch_size = len(prompt) if isinstance(prompt, list) else 1
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# split prompt into 75 token chunks
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tokens = self.tokenizer(
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prompt,
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padding="max_length",
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return_tensors="np",
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max_length=self.tokenizer.model_max_length,
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truncation=False,
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)
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groups_count = ceil(tokens.input_ids.shape[1] / MAX_TOKENS_PER_GROUP)
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logger.info("splitting %s into %s groups", tokens.input_ids.shape, groups_count)
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groups = []
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# np.array_split(tokens.input_ids, groups_count, axis=1)
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for i in range(groups_count):
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group_start = i * MAX_TOKENS_PER_GROUP
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group_end = min(
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group_start + MAX_TOKENS_PER_GROUP, tokens.input_ids.shape[1]
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) # or should this be 1?
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logger.info("building group for token slice [%s : %s]", group_start, group_end)
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groups.append(tokens.input_ids[:, group_start:group_end])
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# encode each chunk
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logger.info("group token shapes: %s", [t.shape for t in groups])
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group_embeds = []
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for group in groups:
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logger.info("encoding group: %s", group.shape)
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embeds = self.text_encoder(input_ids=group.astype(np.int32))[0]
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group_embeds.append(embeds)
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# concat those embeds
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logger.info("group embeds shape: %s", [t.shape for t in group_embeds])
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prompt_embeds = np.concatenate(group_embeds, axis=1)
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prompt_embeds = np.repeat(prompt_embeds, num_images_per_prompt, axis=0)
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# get unconditional embeddings for classifier free guidance
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if do_classifier_free_guidance:
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uncond_tokens: List[str]
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if negative_prompt is None:
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uncond_tokens = [""] * batch_size
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elif type(prompt) is not type(negative_prompt):
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raise TypeError(
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f"`negative_prompt` should be the same type to `prompt`, but got {type(negative_prompt)} !="
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f" {type(prompt)}."
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)
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elif isinstance(negative_prompt, str):
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uncond_tokens = [negative_prompt] * batch_size
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elif batch_size != len(negative_prompt):
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raise ValueError(
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f"`negative_prompt`: {negative_prompt} has batch size {len(negative_prompt)}, but `prompt`:"
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f" {prompt} has batch size {batch_size}. Please make sure that passed `negative_prompt` matches"
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" the batch size of `prompt`."
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)
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else:
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uncond_tokens = negative_prompt
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uncond_input = self.tokenizer(
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uncond_tokens,
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padding="max_length",
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max_length=self.tokenizer.model_max_length,
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truncation=True,
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return_tensors="np",
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)
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negative_prompt_embeds = self.text_encoder(
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input_ids=uncond_input.input_ids.astype(np.int32)
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)[0]
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negative_padding = tokens.input_ids.shape[1] - negative_prompt_embeds.shape[1]
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logger.info(
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"padding negative prompt to match input: %s, %s, %s extra tokens",
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tokens.input_ids.shape,
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negative_prompt_embeds.shape,
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negative_padding,
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)
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negative_prompt_embeds = np.pad(
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negative_prompt_embeds,
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[(0, 0), (0, negative_padding), (0, 0)],
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mode="constant",
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constant_values=0,
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)
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negative_prompt_embeds = np.repeat(
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negative_prompt_embeds, num_images_per_prompt, axis=0
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)
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# For classifier free guidance, we need to do two forward passes.
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# Here we concatenate the unconditional and text embeddings into a single batch
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# to avoid doing two forward passes
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prompt_embeds = np.concatenate([negative_prompt_embeds, prompt_embeds])
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logger.info("expanded prompt shape: %s", prompt_embeds.shape)
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return prompt_embeds
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