308 lines
13 KiB
Python
308 lines
13 KiB
Python
import math
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from collections import namedtuple
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import torch
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from modules import prompt_parser, devices, sd_hijack
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from modules.shared import opts
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class PromptChunk:
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"""
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This object contains token ids, weight (multipliers:1.4) and textual inversion embedding info for a chunk of prompt.
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If a prompt is short, it is represented by one PromptChunk, otherwise, multiple are necessary.
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Each PromptChunk contains an exact amount of tokens - 77, which includes one for start and end token,
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so just 75 tokens from prompt.
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"""
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def __init__(self):
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self.tokens = []
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self.multipliers = []
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self.fixes = []
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PromptChunkFix = namedtuple('PromptChunkFix', ['offset', 'embedding'])
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"""An object of this type is a marker showing that textual inversion embedding's vectors have to placed at offset in the prompt
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chunk. Thos objects are found in PromptChunk.fixes and, are placed into FrozenCLIPEmbedderWithCustomWordsBase.hijack.fixes, and finally
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are applied by sd_hijack.EmbeddingsWithFixes's forward function."""
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class FrozenCLIPEmbedderWithCustomWordsBase(torch.nn.Module):
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"""A pytorch module that is a wrapper for FrozenCLIPEmbedder module. it enhances FrozenCLIPEmbedder, making it possible to
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have unlimited prompt length and assign weights to tokens in prompt.
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"""
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def __init__(self, wrapped, hijack):
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super().__init__()
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self.wrapped = wrapped
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"""Original FrozenCLIPEmbedder module; can also be FrozenOpenCLIPEmbedder or xlmr.BertSeriesModelWithTransformation,
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depending on model."""
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self.hijack: sd_hijack.StableDiffusionModelHijack = hijack
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self.chunk_length = 75
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def empty_chunk(self):
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"""creates an empty PromptChunk and returns it"""
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chunk = PromptChunk()
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chunk.tokens = [self.id_start] + [self.id_end] * (self.chunk_length + 1)
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chunk.multipliers = [1.0] * (self.chunk_length + 2)
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return chunk
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def get_target_prompt_token_count(self, token_count):
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"""returns the maximum number of tokens a prompt of a known length can have before it requires one more PromptChunk to be represented"""
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return math.ceil(max(token_count, 1) / self.chunk_length) * self.chunk_length
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def tokenize(self, texts):
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"""Converts a batch of texts into a batch of token ids"""
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raise NotImplementedError
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def encode_with_transformers(self, tokens):
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"""
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converts a batch of token ids (in python lists) into a single tensor with numeric respresentation of those tokens;
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All python lists with tokens are assumed to have same length, usually 77.
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if input is a list with B elements and each element has T tokens, expected output shape is (B, T, C), where C depends on
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model - can be 768 and 1024.
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Among other things, this call will read self.hijack.fixes, apply it to its inputs, and clear it (setting it to None).
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"""
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raise NotImplementedError
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def encode_embedding_init_text(self, init_text, nvpt):
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"""Converts text into a tensor with this text's tokens' embeddings. Note that those are embeddings before they are passed through
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transformers. nvpt is used as a maximum length in tokens. If text produces less teokens than nvpt, only this many is returned."""
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raise NotImplementedError
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def tokenize_line(self, line):
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"""
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this transforms a single prompt into a list of PromptChunk objects - as many as needed to
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represent the prompt.
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Returns the list and the total number of tokens in the prompt.
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"""
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if opts.enable_emphasis:
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parsed = prompt_parser.parse_prompt_attention(line)
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else:
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parsed = [[line, 1.0]]
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tokenized = self.tokenize([text for text, _ in parsed])
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chunks = []
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chunk = PromptChunk()
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token_count = 0
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last_comma = -1
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def next_chunk():
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"""puts current chunk into the list of results and produces the next one - empty"""
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nonlocal token_count
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nonlocal last_comma
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nonlocal chunk
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token_count += len(chunk.tokens)
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to_add = self.chunk_length - len(chunk.tokens)
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if to_add > 0:
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chunk.tokens += [self.id_end] * to_add
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chunk.multipliers += [1.0] * to_add
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chunk.tokens = [self.id_start] + chunk.tokens + [self.id_end]
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chunk.multipliers = [1.0] + chunk.multipliers + [1.0]
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last_comma = -1
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chunks.append(chunk)
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chunk = PromptChunk()
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for tokens, (text, weight) in zip(tokenized, parsed):
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position = 0
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while position < len(tokens):
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token = tokens[position]
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if token == self.comma_token:
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last_comma = len(chunk.tokens)
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# this is when we are at the end of alloted 75 tokens for the current chunk, and the current token is not a comma. opts.comma_padding_backtrack
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# is a setting that specifies that if there is a comma nearby, the text after the comma should be moved out of this chunk and into the next.
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elif opts.comma_padding_backtrack != 0 and len(chunk.tokens) == self.chunk_length and last_comma != -1 and len(chunk.tokens) - last_comma <= opts.comma_padding_backtrack:
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break_location = last_comma + 1
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reloc_tokens = chunk.tokens[break_location:]
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reloc_mults = chunk.multipliers[break_location:]
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chunk.tokens = chunk.tokens[:break_location]
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chunk.multipliers = chunk.multipliers[:break_location]
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next_chunk()
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chunk.tokens = reloc_tokens
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chunk.multipliers = reloc_mults
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if len(chunk.tokens) == self.chunk_length:
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next_chunk()
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embedding, embedding_length_in_tokens = self.hijack.embedding_db.find_embedding_at_position(tokens, position)
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if embedding is None:
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chunk.tokens.append(token)
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chunk.multipliers.append(weight)
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position += 1
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continue
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emb_len = int(embedding.vec.shape[0])
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if len(chunk.tokens) + emb_len > self.chunk_length:
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next_chunk()
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chunk.fixes.append(PromptChunkFix(len(chunk.tokens), embedding))
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chunk.tokens += [0] * emb_len
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chunk.multipliers += [weight] * emb_len
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position += embedding_length_in_tokens
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if len(chunk.tokens) > 0 or len(chunks) == 0:
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next_chunk()
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return chunks, token_count
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def process_texts(self, texts):
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"""
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Accepts a list of texts and calls tokenize_line() on each, with cache. Returns the list of results and maximum
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length, in tokens, of all texts.
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"""
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token_count = 0
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cache = {}
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batch_chunks = []
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for line in texts:
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if line in cache:
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chunks = cache[line]
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else:
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chunks, current_token_count = self.tokenize_line(line)
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token_count = max(current_token_count, token_count)
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cache[line] = chunks
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batch_chunks.append(chunks)
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return batch_chunks, token_count
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def forward(self, texts):
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"""
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Accepts an array of texts; Passes texts through transformers network to create a tensor with numerical representation of those texts.
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Returns a tensor with shape of (B, T, C), where B is length of the array; T is length, in tokens, of texts (including padding) - T will
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be a multiple of 77; and C is dimensionality of each token - for SD1 it's 768, and for SD2 it's 1024.
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An example shape returned by this function can be: (2, 77, 768).
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Webui usually sends just one text at a time through this function - the only time when texts is an array with more than one elemenet
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is when you do prompt editing: "a picture of a [cat:dog:0.4] eating ice cream"
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"""
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if opts.use_old_emphasis_implementation:
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import modules.sd_hijack_clip_old
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return modules.sd_hijack_clip_old.forward_old(self, texts)
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batch_chunks, token_count = self.process_texts(texts)
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used_embeddings = {}
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chunk_count = max([len(x) for x in batch_chunks])
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zs = []
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for i in range(chunk_count):
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batch_chunk = [chunks[i] if i < len(chunks) else self.empty_chunk() for chunks in batch_chunks]
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tokens = [x.tokens for x in batch_chunk]
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multipliers = [x.multipliers for x in batch_chunk]
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self.hijack.fixes = [x.fixes for x in batch_chunk]
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for fixes in self.hijack.fixes:
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for position, embedding in fixes:
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used_embeddings[embedding.name] = embedding
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z = self.process_tokens(tokens, multipliers)
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zs.append(z)
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if len(used_embeddings) > 0:
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embeddings_list = ", ".join([f'{name} [{embedding.checksum()}]' for name, embedding in used_embeddings.items()])
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self.hijack.comments.append(f"Used embeddings: {embeddings_list}")
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return torch.hstack(zs)
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def process_tokens(self, remade_batch_tokens, batch_multipliers):
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"""
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sends one single prompt chunk to be encoded by transformers neural network.
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remade_batch_tokens is a batch of tokens - a list, where every element is a list of tokens; usually
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there are exactly 77 tokens in the list. batch_multipliers is the same but for multipliers instead of tokens.
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Multipliers are used to give more or less weight to the outputs of transformers network. Each multiplier
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corresponds to one token.
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"""
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tokens = torch.asarray(remade_batch_tokens).to(devices.device)
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# this is for SD2: SD1 uses the same token for padding and end of text, while SD2 uses different ones.
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if self.id_end != self.id_pad:
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for batch_pos in range(len(remade_batch_tokens)):
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index = remade_batch_tokens[batch_pos].index(self.id_end)
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tokens[batch_pos, index+1:tokens.shape[1]] = self.id_pad
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z = self.encode_with_transformers(tokens)
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# restoring original mean is likely not correct, but it seems to work well to prevent artifacts that happen otherwise
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batch_multipliers = torch.asarray(batch_multipliers).to(devices.device)
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original_mean = z.mean()
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z = z * batch_multipliers.reshape(batch_multipliers.shape + (1,)).expand(z.shape)
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new_mean = z.mean()
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z = z * (original_mean / new_mean)
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return z
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class FrozenCLIPEmbedderWithCustomWords(FrozenCLIPEmbedderWithCustomWordsBase):
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def __init__(self, wrapped, hijack):
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super().__init__(wrapped, hijack)
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self.tokenizer = wrapped.tokenizer
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vocab = self.tokenizer.get_vocab()
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self.comma_token = vocab.get(',</w>', None)
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self.token_mults = {}
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tokens_with_parens = [(k, v) for k, v in vocab.items() if '(' in k or ')' in k or '[' in k or ']' in k]
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for text, ident in tokens_with_parens:
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mult = 1.0
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for c in text:
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if c == '[':
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mult /= 1.1
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if c == ']':
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mult *= 1.1
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if c == '(':
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mult *= 1.1
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if c == ')':
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mult /= 1.1
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if mult != 1.0:
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self.token_mults[ident] = mult
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self.id_start = self.wrapped.tokenizer.bos_token_id
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self.id_end = self.wrapped.tokenizer.eos_token_id
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self.id_pad = self.id_end
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def tokenize(self, texts):
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tokenized = self.wrapped.tokenizer(texts, truncation=False, add_special_tokens=False)["input_ids"]
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return tokenized
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def encode_with_transformers(self, tokens):
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outputs = self.wrapped.transformer(input_ids=tokens, output_hidden_states=-opts.CLIP_stop_at_last_layers)
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if opts.CLIP_stop_at_last_layers > 1:
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z = outputs.hidden_states[-opts.CLIP_stop_at_last_layers]
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z = self.wrapped.transformer.text_model.final_layer_norm(z)
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else:
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z = outputs.last_hidden_state
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return z
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def encode_embedding_init_text(self, init_text, nvpt):
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embedding_layer = self.wrapped.transformer.text_model.embeddings
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ids = self.wrapped.tokenizer(init_text, max_length=nvpt, return_tensors="pt", add_special_tokens=False)["input_ids"]
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embedded = embedding_layer.token_embedding.wrapped(ids.to(embedding_layer.token_embedding.wrapped.weight.device)).squeeze(0)
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return embedded
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