clip_text_custom_embedder

README.md

Usage

from clip_text_custom_embedder import text_embeddings
from diffusers import StableDiffusionPipeline
import torch

pipe = StableDiffusionPipeline.from_pretrained(model_id, torch_dtype=torch.float16).to('cuda')

prompt = "((masterpiece, best quality)), white background, close-up, 1girl, litte smile"
negative_prompt = ("(low quality, worst quality:1.4), (bad anatomy), (inaccurate limb:1.2), "
                   "bad composition, inaccurate eyes, extra digit, fewer digits, (extra arms:1.2), partial face, "
                   "partial head, cropped head")
cond, uncond = text_embeddings(pipe, prompt, negative_prompt, clip_stop_at_last_layers=2)

images = pipe(prompt_embeds=cond, 
              negative_prompt_embeds=uncond, 
              generator=torch.manual_seed(seed)).images[0]        

clip_text_custom_embedder.py

import torch
import math
import re

# copied and customized from automatic1111 sd_hijack.py & prompt_parser.py
# https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/ec1924ee5789b72c31c65932b549c59ccae0cdd6/modules/sd_hijack.py#L113
# https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/ec1924ee5789b72c31c65932b549c59ccae0cdd6/modules/prompt_parser.py#L259

re_attention = re.compile(r"""
\\\(|
\\\{|
\\\)|
\\\}|
\\\[|
\\]|
\\\\|
\\|
\(|
\{|
\[|
:([+-]?[.\d]+)\)|
\)|
\}|
]|
[^\\()\\{}\[\]:]+|
:
""", re.X)


def parse_prompt_attention(text):
    """
    Parses a string with attention tokens and returns a list of pairs: text and its assoicated weight.
    Accepted tokens are:
      (abc) - increases attention to abc by a multiplier of 1.1
      (abc:3.12) - increases attention to abc by a multiplier of 3.12
      [abc] - decreases attention to abc by a multiplier of 1.1
      \( - literal character '('
      \[ - literal character '['
      \) - literal character ')'
      \] - literal character ']'
      \\ - literal character '\'
      anything else - just text

    >>> parse_prompt_attention('normal text')
    [['normal text', 1.0]]
    >>> parse_prompt_attention('an (important) word')
    [['an ', 1.0], ['important', 1.1], [' word', 1.0]]
    >>> parse_prompt_attention('(unbalanced')
    [['unbalanced', 1.1]]
    >>> parse_prompt_attention('\(literal\]')
    [['(literal]', 1.0]]
    >>> parse_prompt_attention('(unnecessary)(parens)')
    [['unnecessaryparens', 1.1]]
    >>> parse_prompt_attention('a (((house:1.3)) [on] a (hill:0.5), sun, (((sky))).')
    [['a ', 1.0],
     ['house', 1.5730000000000004],
     [' ', 1.1],
     ['on', 1.0],
     [' a ', 1.1],
     ['hill', 0.55],
     [', sun, ', 1.1],
     ['sky', 1.4641000000000006],
     ['.', 1.1]]
    """

    res = []
    round_brackets = []
    square_brackets = []

    round_bracket_multiplier = 1.1
    square_bracket_multiplier = 1 / 1.1

    def multiply_range(start_position, multiplier):
        for p in range(start_position, len(res)):
            res[p][1] *= multiplier

    for m in re_attention.finditer(text):
        text = m.group(0)
        weight = m.group(1)

        if text.startswith('\\'):
            res.append([text[1:], 1.0])
        elif text == '(' or text == '{':
            round_brackets.append(len(res))
        elif text == '[':
            square_brackets.append(len(res))
        elif weight is not None and len(round_brackets) > 0:
            multiply_range(round_brackets.pop(), float(weight))
        elif (text == ')' or text == '}') and len(round_brackets) > 0:
            multiply_range(round_brackets.pop(), round_bracket_multiplier)
        elif text == ']' and len(square_brackets) > 0:
            multiply_range(square_brackets.pop(), square_bracket_multiplier)
        else:
            res.append([text, 1.0])

    for pos in round_brackets:
        multiply_range(pos, round_bracket_multiplier)

    for pos in square_brackets:
        multiply_range(pos, square_bracket_multiplier)

    if len(res) == 0:
        res = [["", 1.0]]

    # merge runs of identical weights
    i = 0
    while i + 1 < len(res):
        if res[i][1] == res[i + 1][1]:
            res[i][0] += res[i + 1][0]
            res.pop(i + 1)
        else:
            i += 1

    return res


class CLIPTextCustomEmbedder(object):
    def __init__(self, tokenizer, text_encoder, device,
                 clip_stop_at_last_layers=1):
        self.tokenizer = tokenizer
        self.text_encoder = text_encoder
        self.token_mults = {}
        self.device = device
        self.clip_stop_at_last_layers = clip_stop_at_last_layers

    def tokenize_line(self, line):
        def get_target_prompt_token_count(token_count):
            return math.ceil(max(token_count, 1) / 75) * 75

        id_end = self.tokenizer.eos_token_id
        parsed = parse_prompt_attention(line)
        tokenized = self.tokenizer(
            [text for text, _ in parsed], truncation=False,
            add_special_tokens=False)["input_ids"]

        fixes = []
        remade_tokens = []
        multipliers = []

        for tokens, (text, weight) in zip(tokenized, parsed):
            i = 0
            while i < len(tokens):
                token = tokens[i]
                remade_tokens.append(token)
                multipliers.append(weight)
                i += 1

        token_count = len(remade_tokens)
        prompt_target_length = get_target_prompt_token_count(token_count)
        tokens_to_add = prompt_target_length - len(remade_tokens)
        remade_tokens = remade_tokens + [id_end] * tokens_to_add
        multipliers = multipliers + [1.0] * tokens_to_add
        return remade_tokens, fixes, multipliers, token_count

    def process_text(self, texts):
        if isinstance(texts, str):
            texts = [texts]

        remade_batch_tokens = []
        cache = {}
        batch_multipliers = []
        for line in texts:
            if line in cache:
                remade_tokens, fixes, multipliers = cache[line]
            else:
                remade_tokens, fixes, multipliers, _ = self.tokenize_line(line)
                cache[line] = (remade_tokens, fixes, multipliers)

            remade_batch_tokens.append(remade_tokens)
            batch_multipliers.append(multipliers)

        return batch_multipliers, remade_batch_tokens

    def __call__(self, text):
        batch_multipliers, remade_batch_tokens = self.process_text(text)

        z = None
        i = 0
        while max(map(len, remade_batch_tokens)) != 0:
            rem_tokens = [x[75:] for x in remade_batch_tokens]
            rem_multipliers = [x[75:] for x in batch_multipliers]

            tokens = []
            multipliers = []
            for j in range(len(remade_batch_tokens)):
                if len(remade_batch_tokens[j]) > 0:
                    tokens.append(remade_batch_tokens[j][:75])
                    multipliers.append(batch_multipliers[j][:75])
                else:
                    tokens.append([self.tokenizer.eos_token_id] * 75)
                    multipliers.append([1.0] * 75)

            z1 = self.process_tokens(tokens, multipliers)
            z = z1 if z is None else torch.cat((z, z1), axis=-2)

            remade_batch_tokens = rem_tokens
            batch_multipliers = rem_multipliers
            i += 1

        return z

    def process_tokens(self, remade_batch_tokens, batch_multipliers):
        remade_batch_tokens = [[self.tokenizer.bos_token_id] + x[:75] +
                               [self.tokenizer.eos_token_id] for x in remade_batch_tokens]
        batch_multipliers = [[1.0] + x[:75] + [1.0] for x in batch_multipliers]

        tokens = torch.asarray(remade_batch_tokens).to(self.device)
        # print(tokens.shape)
        # print(tokens)
        outputs = self.text_encoder(
            input_ids=tokens, output_hidden_states=True)

        if self.clip_stop_at_last_layers > 1:
            z = self.text_encoder.text_model.final_layer_norm(
                outputs.hidden_states[-self.clip_stop_at_last_layers])
        else:
            z = outputs.last_hidden_state

        # restoring original mean is likely not correct, but it seems to work well
        # to prevent artifacts that happen otherwise
        batch_multipliers_of_same_length = [
            x + [1.0] * (75 - len(x)) for x in batch_multipliers]
        batch_multipliers = torch.asarray(
            batch_multipliers_of_same_length).to(self.device)
        # print(batch_multipliers.shape)
        # print(batch_multipliers)

        original_mean = z.mean()
        z *= batch_multipliers.reshape(batch_multipliers.shape +
                                       (1,)).expand(z.shape)
        new_mean = z.mean()
        z *= original_mean / new_mean

        return z

    def get_text_tokens(self, text):
        batch_multipliers, remade_batch_tokens = self.process_text(text)
        return [[self.tokenizer.bos_token_id] + remade_batch_tokens[0]], \
            [[1.0] + batch_multipliers[0]]


def text_embeddings_equal_len(text_embedder, prompt, negative_prompt):
    cond_embeddings = text_embedder(prompt)
    uncond_embeddings = text_embedder(negative_prompt)

    cond_len = cond_embeddings.shape[1]
    uncond_len = uncond_embeddings.shape[1]
    if cond_len == uncond_len:
        return cond_embeddings, uncond_embeddings
    else:
        if cond_len > uncond_len:
            n = (cond_len - uncond_len) // 77
            return cond_embeddings, torch.cat([uncond_embeddings] + [text_embedder("")]*n, dim=1)
        else:
            n = (uncond_len - cond_len) // 77
            return torch.cat([cond_embeddings] + [text_embedder("")]*n, dim=1), uncond_embeddings
        

def text_embeddings(pipe, prompt, negative_prompt, clip_stop_at_last_layers=1):
    text_embedder = CLIPTextCustomEmbedder(tokenizer=pipe.tokenizer,
                                           text_encoder=pipe.text_encoder,
                                           device=pipe.text_encoder.device,
                                           clip_stop_at_last_layers=clip_stop_at_last_layers)
    cond_embeddings, uncond_embeddings = text_embeddings_equal_len(text_embedder, prompt, negative_prompt)
    return cond_embeddings, uncond_embeddings
        

@takuma104 can you update clip_text_custom_embedder for SDXL please?