InvokeAI/ldm/modules/embedding_manager.py

from cmath import log
import torch
from torch import nn

import sys

from ldm.data.personalized import per_img_token_list
from transformers import CLIPTokenizer
from functools import partial

DEFAULT_PLACEHOLDER_TOKEN = ['*']

PROGRESSIVE_SCALE = 2000


def get_clip_token_for_string(tokenizer, string):
    batch_encoding = tokenizer(
        string,
        truncation=True,
        max_length=77,
        return_length=True,
        return_overflowing_tokens=False,
        padding='max_length',
        return_tensors='pt',
    )
    tokens = batch_encoding['input_ids']
    assert (
        torch.count_nonzero(tokens - 49407) == 2
    ), f"String '{string}' maps to more than a single token. Please use another string"

    return tokens[0, 1]


def get_bert_token_for_string(tokenizer, string):
    token = tokenizer(string)
    # assert torch.count_nonzero(token) == 3, f"String '{string}' maps to more than a single token. Please use another string"

    token = token[0, 1]

    return token


def get_embedding_for_clip_token(embedder, token):
    return embedder(token.unsqueeze(0))[0, 0]


class EmbeddingManager(nn.Module):
    def __init__(
        self,
        embedder,
        placeholder_strings=None,
        initializer_words=None,
        per_image_tokens=False,
        num_vectors_per_token=1,
        progressive_words=False,
        **kwargs,
    ):
        super().__init__()

        self.string_to_token_dict = {}

        self.string_to_param_dict = nn.ParameterDict()

        self.initial_embeddings = (
            nn.ParameterDict()
        )   # These should not be optimized

        self.progressive_words = progressive_words
        self.progressive_counter = 0

        self.max_vectors_per_token = num_vectors_per_token

        if hasattr(
            embedder, 'tokenizer'
        ):   # using Stable Diffusion's CLIP encoder
            self.is_clip = True
            get_token_for_string = partial(
                get_clip_token_for_string, embedder.tokenizer
            )
            get_embedding_for_tkn = partial(
                get_embedding_for_clip_token,
                embedder.transformer.text_model.embeddings,
            )
            token_dim = 1280
        else:   # using LDM's BERT encoder
            self.is_clip = False
            get_token_for_string = partial(
                get_bert_token_for_string, embedder.tknz_fn
            )
            get_embedding_for_tkn = embedder.transformer.token_emb
            token_dim = 1280

        if per_image_tokens:
            placeholder_strings.extend(per_img_token_list)

        for idx, placeholder_string in enumerate(placeholder_strings):

            token = get_token_for_string(placeholder_string)

            if initializer_words and idx < len(initializer_words):
                init_word_token = get_token_for_string(initializer_words[idx])

                with torch.no_grad():
                    init_word_embedding = get_embedding_for_tkn(
                        init_word_token.cpu()
                    )

                token_params = torch.nn.Parameter(
                    init_word_embedding.unsqueeze(0).repeat(
                        num_vectors_per_token, 1
                    ),
                    requires_grad=True,
                )
                self.initial_embeddings[
                    placeholder_string
                ] = torch.nn.Parameter(
                    init_word_embedding.unsqueeze(0).repeat(
                        num_vectors_per_token, 1
                    ),
                    requires_grad=False,
                )
            else:
                token_params = torch.nn.Parameter(
                    torch.rand(
                        size=(num_vectors_per_token, token_dim),
                        requires_grad=True,
                    )
                )

            self.string_to_token_dict[placeholder_string] = token
            self.string_to_param_dict[placeholder_string] = token_params

    def forward(
        self,
        tokenized_text,
        embedded_text,
    ):
        b, n, device = *tokenized_text.shape, tokenized_text.device

        for (
            placeholder_string,
            placeholder_token,
        ) in self.string_to_token_dict.items():

            placeholder_embedding = self.string_to_param_dict[
                placeholder_string
            ].to(device)

            if (
                self.max_vectors_per_token == 1
            ):   # If there's only one vector per token, we can do a simple replacement
                placeholder_idx = torch.where(
                    tokenized_text == placeholder_token.to(device)
                )
                embedded_text[placeholder_idx] = placeholder_embedding
            else:   # otherwise, need to insert and keep track of changing indices
                if self.progressive_words:
                    self.progressive_counter += 1
                    max_step_tokens = (
                        1 + self.progressive_counter // PROGRESSIVE_SCALE
                    )
                else:
                    max_step_tokens = self.max_vectors_per_token

                num_vectors_for_token = min(
                    placeholder_embedding.shape[0], max_step_tokens
                )

                placeholder_rows, placeholder_cols = torch.where(
                    tokenized_text == placeholder_token.to(device)
                )

                if placeholder_rows.nelement() == 0:
                    continue

                sorted_cols, sort_idx = torch.sort(
                    placeholder_cols, descending=True
                )
                sorted_rows = placeholder_rows[sort_idx]

                for idx in range(len(sorted_rows)):
                    row = sorted_rows[idx]
                    col = sorted_cols[idx]

                    new_token_row = torch.cat(
                        [
                            tokenized_text[row][:col],
                            placeholder_token.repeat(num_vectors_for_token).to(
                                device
                            ),
                            tokenized_text[row][col + 1 :],
                        ],
                        axis=0,
                    )[:n]
                    new_embed_row = torch.cat(
                        [
                            embedded_text[row][:col],
                            placeholder_embedding[:num_vectors_for_token],
                            embedded_text[row][col + 1 :],
                        ],
                        axis=0,
                    )[:n]

                    embedded_text[row] = new_embed_row
                    tokenized_text[row] = new_token_row

        return embedded_text

    def save(self, ckpt_path):
        torch.save(
            {
                'string_to_token': self.string_to_token_dict,
                'string_to_param': self.string_to_param_dict,
            },
            ckpt_path,
        )

    def load(self, ckpt_path, full=True):
        ckpt = torch.load(ckpt_path, map_location='cpu')
        self.string_to_token_dict = ckpt["string_to_token"]
        self.string_to_param_dict = ckpt["string_to_param"]
        if not full:
            for key, value in self.string_to_param_dict.items():
                self.string_to_param_dict[key] = torch.nn.Parameter(value.half())

    def get_embedding_norms_squared(self):
        all_params = torch.cat(
            list(self.string_to_param_dict.values()), axis=0
        )   # num_placeholders x embedding_dim
        param_norm_squared = (all_params * all_params).sum(
            axis=-1
        )              # num_placeholders

        return param_norm_squared

    def embedding_parameters(self):
        return self.string_to_param_dict.parameters()

    def embedding_to_coarse_loss(self):

        loss = 0.0
        num_embeddings = len(self.initial_embeddings)

        for key in self.initial_embeddings:
            optimized = self.string_to_param_dict[key]
            coarse = self.initial_embeddings[key].clone().to(optimized.device)

            loss = (
                loss
                + (optimized - coarse)
                @ (optimized - coarse).T
                / num_embeddings
            )

        return loss