library/sdxl_model_util.py

import torch
import safetensors
from accelerate import init_empty_weights
from accelerate.utils.modeling import set_module_tensor_to_device
from safetensors.torch import load_file, save_file
from transformers import CLIPTextModel, CLIPTextConfig, CLIPTextModelWithProjection, CLIPTokenizer
from typing import List
from diffusers import AutoencoderKL, EulerDiscreteScheduler, UNet2DConditionModel
from . import model_util
from . import sdxl_original_unet
from .utils import setup_logging

setup_logging()
import logging

logger = logging.getLogger(__name__)

VAE_SCALE_FACTOR = 0.13025
MODEL_VERSION_SDXL_BASE_V1_0 = "sdxl_base_v1-0"

# Diffusersの設定を読み込むための参照モデル
DIFFUSERS_REF_MODEL_ID_SDXL = "stabilityai/stable-diffusion-xl-base-1.0"

DIFFUSERS_SDXL_UNET_CONFIG = {
    "act_fn": "silu",
    "addition_embed_type": "text_time",
    "addition_embed_type_num_heads": 64,
    "addition_time_embed_dim": 256,
    "attention_head_dim": [5, 10, 20],
    "block_out_channels": [320, 640, 1280],
    "center_input_sample": False,
    "class_embed_type": None,
    "class_embeddings_concat": False,
    "conv_in_kernel": 3,
    "conv_out_kernel": 3,
    "cross_attention_dim": 2048,
    "cross_attention_norm": None,
    "down_block_types": ["DownBlock2D", "CrossAttnDownBlock2D", "CrossAttnDownBlock2D"],
    "downsample_padding": 1,
    "dual_cross_attention": False,
    "encoder_hid_dim": None,
    "encoder_hid_dim_type": None,
    "flip_sin_to_cos": True,
    "freq_shift": 0,
    "in_channels": 4,
    "layers_per_block": 2,
    "mid_block_only_cross_attention": None,
    "mid_block_scale_factor": 1,
    "mid_block_type": "UNetMidBlock2DCrossAttn",
    "norm_eps": 1e-05,
    "norm_num_groups": 32,
    "num_attention_heads": None,
    "num_class_embeds": None,
    "only_cross_attention": False,
    "out_channels": 4,
    "projection_class_embeddings_input_dim": 2816,
    "resnet_out_scale_factor": 1.0,
    "resnet_skip_time_act": False,
    "resnet_time_scale_shift": "default",
    "sample_size": 128,
    "time_cond_proj_dim": None,
    "time_embedding_act_fn": None,
    "time_embedding_dim": None,
    "time_embedding_type": "positional",
    "timestep_post_act": None,
    "transformer_layers_per_block": [1, 2, 10],
    "up_block_types": ["CrossAttnUpBlock2D", "CrossAttnUpBlock2D", "UpBlock2D"],
    "upcast_attention": False,
    "use_linear_projection": True,
}


def convert_sdxl_text_encoder_2_checkpoint(checkpoint, max_length):
    SDXL_KEY_PREFIX = "conditioner.embedders.1.model."

    # SD2のと、基本的には同じ。logit_scaleを後で使うので、それを追加で返す
    # logit_scaleはcheckpointの保存時に使用する
    def convert_key(key):
        # common conversion
        key = key.replace(SDXL_KEY_PREFIX + "transformer.", "text_model.encoder.")
        key = key.replace(SDXL_KEY_PREFIX, "text_model.")

        if "resblocks" in key:
            # resblocks conversion
            key = key.replace(".resblocks.", ".layers.")
            if ".ln_" in key:
                key = key.replace(".ln_", ".layer_norm")
            elif ".mlp." in key:
                key = key.replace(".c_fc.", ".fc1.")
                key = key.replace(".c_proj.", ".fc2.")
            elif ".attn.out_proj" in key:
                key = key.replace(".attn.out_proj.", ".self_attn.out_proj.")
            elif ".attn.in_proj" in key:
                key = None  # 特殊なので後で処理する
            else:
                raise ValueError(f"unexpected key in SD: {key}")
        elif ".positional_embedding" in key:
            key = key.replace(".positional_embedding", ".embeddings.position_embedding.weight")
        elif ".text_projection" in key:
            key = key.replace("text_model.text_projection", "text_projection.weight")
        elif ".logit_scale" in key:
            key = None  # 後で処理する
        elif ".token_embedding" in key:
            key = key.replace(".token_embedding.weight", ".embeddings.token_embedding.weight")
        elif ".ln_final" in key:
            key = key.replace(".ln_final", ".final_layer_norm")
        # ckpt from comfy has this key: text_model.encoder.text_model.embeddings.position_ids
        elif ".embeddings.position_ids" in key:
            key = None  # remove this key: position_ids is not used in newer transformers
        return key

    keys = list(checkpoint.keys())
    new_sd = {}
    for key in keys:
        new_key = convert_key(key)
        if new_key is None:
            continue
        new_sd[new_key] = checkpoint[key]

    # attnの変換
    for key in keys:
        if ".resblocks" in key and ".attn.in_proj_" in key:
            # 三つに分割
            values = torch.chunk(checkpoint[key], 3)

            key_suffix = ".weight" if "weight" in key else ".bias"
            key_pfx = key.replace(SDXL_KEY_PREFIX + "transformer.resblocks.", "text_model.encoder.layers.")
            key_pfx = key_pfx.replace("_weight", "")
            key_pfx = key_pfx.replace("_bias", "")
            key_pfx = key_pfx.replace(".attn.in_proj", ".self_attn.")
            new_sd[key_pfx + "q_proj" + key_suffix] = values[0]
            new_sd[key_pfx + "k_proj" + key_suffix] = values[1]
            new_sd[key_pfx + "v_proj" + key_suffix] = values[2]

    # logit_scale はDiffusersには含まれないが、保存時に戻したいので別途返す
    logit_scale = checkpoint.get(SDXL_KEY_PREFIX + "logit_scale", None)

    # temporary workaround for text_projection.weight.weight for Playground-v2
    if "text_projection.weight.weight" in new_sd:
        logger.info("convert_sdxl_text_encoder_2_checkpoint: convert text_projection.weight.weight to text_projection.weight")
        new_sd["text_projection.weight"] = new_sd["text_projection.weight.weight"]
        del new_sd["text_projection.weight.weight"]

    return new_sd, logit_scale


# load state_dict without allocating new tensors
def _load_state_dict_on_device(model, state_dict, device, dtype=None):
    # dtype will use fp32 as default
    missing_keys = list(model.state_dict().keys() - state_dict.keys())
    unexpected_keys = list(state_dict.keys() - model.state_dict().keys())

    # similar to model.load_state_dict()
    if not missing_keys and not unexpected_keys:
        for k in list(state_dict.keys()):
            set_module_tensor_to_device(model, k, device, value=state_dict.pop(k), dtype=dtype)
        return "<All keys matched successfully>"

    # error_msgs
    error_msgs: List[str] = []
    if missing_keys:
        error_msgs.insert(0, "Missing key(s) in state_dict: {}. ".format(", ".join('"{}"'.format(k) for k in missing_keys)))
    if unexpected_keys:
        error_msgs.insert(0, "Unexpected key(s) in state_dict: {}. ".format(", ".join('"{}"'.format(k) for k in unexpected_keys)))

    raise RuntimeError("Error(s) in loading state_dict for {}:\n\t{}".format(model.__class__.__name__, "\n\t".join(error_msgs)))


def load_models_from_sdxl_checkpoint(model_version, ckpt_path, map_location, dtype=None, disable_mmap=False):
    # model_version is reserved for future use
    # dtype is used for full_fp16/bf16 integration. Text Encoder will remain fp32, because it runs on CPU when caching

    # Load the state dict
    if model_util.is_safetensors(ckpt_path):
        checkpoint = None
        if disable_mmap:
            state_dict = safetensors.torch.load(open(ckpt_path, "rb").read())
        else:
            try:
                state_dict = load_file(ckpt_path, device=map_location)
            except:
                state_dict = load_file(ckpt_path)  # prevent device invalid Error
        epoch = None
        global_step = None
    else:
        checkpoint = torch.load(ckpt_path, map_location=map_location)
        if "state_dict" in checkpoint:
            state_dict = checkpoint["state_dict"]
            epoch = checkpoint.get("epoch", 0)
            global_step = checkpoint.get("global_step", 0)
        else:
            state_dict = checkpoint
            epoch = 0
            global_step = 0
        checkpoint = None

    # U-Net
    logger.info("building U-Net")
    with init_empty_weights():
        unet = sdxl_original_unet.SdxlUNet2DConditionModel()

    logger.info("loading U-Net from checkpoint")
    unet_sd = {}
    for k in list(state_dict.keys()):
        if k.startswith("model.diffusion_model."):
            unet_sd[k.replace("model.diffusion_model.", "")] = state_dict.pop(k)
    info = _load_state_dict_on_device(unet, unet_sd, device=map_location, dtype=dtype)
    logger.info(f"U-Net: {info}")

    # Text Encoders
    logger.info("building text encoders")

    # Text Encoder 1 is same to Stability AI's SDXL
    text_model1_cfg = CLIPTextConfig(
        vocab_size=49408,
        hidden_size=768,
        intermediate_size=3072,
        num_hidden_layers=12,
        num_attention_heads=12,
        max_position_embeddings=77,
        hidden_act="quick_gelu",
        layer_norm_eps=1e-05,
        dropout=0.0,
        attention_dropout=0.0,
        initializer_range=0.02,
        initializer_factor=1.0,
        pad_token_id=1,
        bos_token_id=0,
        eos_token_id=2,
        model_type="clip_text_model",
        projection_dim=768,
        # torch_dtype="float32",
        # transformers_version="4.25.0.dev0",
    )
    with init_empty_weights():
        text_model1 = CLIPTextModel._from_config(text_model1_cfg)

    # Text Encoder 2 is different from Stability AI's SDXL. SDXL uses open clip, but we use the model from HuggingFace.
    # Note: Tokenizer from HuggingFace is different from SDXL. We must use open clip's tokenizer.
    text_model2_cfg = CLIPTextConfig(
        vocab_size=49408,
        hidden_size=1280,
        intermediate_size=5120,
        num_hidden_layers=32,
        num_attention_heads=20,
        max_position_embeddings=77,
        hidden_act="gelu",
        layer_norm_eps=1e-05,
        dropout=0.0,
        attention_dropout=0.0,
        initializer_range=0.02,
        initializer_factor=1.0,
        pad_token_id=1,
        bos_token_id=0,
        eos_token_id=2,
        model_type="clip_text_model",
        projection_dim=1280,
        # torch_dtype="float32",
        # transformers_version="4.25.0.dev0",
    )
    with init_empty_weights():
        text_model2 = CLIPTextModelWithProjection(text_model2_cfg)

    logger.info("loading text encoders from checkpoint")
    te1_sd = {}
    te2_sd = {}
    for k in list(state_dict.keys()):
        if k.startswith("conditioner.embedders.0.transformer."):
            te1_sd[k.replace("conditioner.embedders.0.transformer.", "")] = state_dict.pop(k)
        elif k.startswith("conditioner.embedders.1.model."):
            te2_sd[k] = state_dict.pop(k)

    # 最新の transformers では position_ids を含むとエラーになるので削除 / remove position_ids for latest transformers
    if "text_model.embeddings.position_ids" in te1_sd:
        te1_sd.pop("text_model.embeddings.position_ids")

    info1 = _load_state_dict_on_device(text_model1, te1_sd, device=map_location)  # remain fp32
    logger.info(f"text encoder 1: {info1}")

    converted_sd, logit_scale = convert_sdxl_text_encoder_2_checkpoint(te2_sd, max_length=77)
    info2 = _load_state_dict_on_device(text_model2, converted_sd, device=map_location)  # remain fp32
    logger.info(f"text encoder 2: {info2}")

    # prepare vae
    logger.info("building VAE")
    vae_config = model_util.create_vae_diffusers_config()
    with init_empty_weights():
        vae = AutoencoderKL(**vae_config)

    logger.info("loading VAE from checkpoint")
    converted_vae_checkpoint = model_util.convert_ldm_vae_checkpoint(state_dict, vae_config)
    info = _load_state_dict_on_device(vae, converted_vae_checkpoint, device=map_location, dtype=dtype)
    logger.info(f"VAE: {info}")

    ckpt_info = (epoch, global_step) if epoch is not None else None
    return text_model1, text_model2, vae, unet, logit_scale, ckpt_info


def make_unet_conversion_map():
    unet_conversion_map_layer = []

    for i in range(3):  # num_blocks is 3 in sdxl
        # loop over downblocks/upblocks
        for j in range(2):
            # loop over resnets/attentions for downblocks
            hf_down_res_prefix = f"down_blocks.{i}.resnets.{j}."
            sd_down_res_prefix = f"input_blocks.{3*i + j + 1}.0."
            unet_conversion_map_layer.append((sd_down_res_prefix, hf_down_res_prefix))

            if i < 3:
                # no attention layers in down_blocks.3
                hf_down_atn_prefix = f"down_blocks.{i}.attentions.{j}."
                sd_down_atn_prefix = f"input_blocks.{3*i + j + 1}.1."
                unet_conversion_map_layer.append((sd_down_atn_prefix, hf_down_atn_prefix))

        for j in range(3):
            # loop over resnets/attentions for upblocks
            hf_up_res_prefix = f"up_blocks.{i}.resnets.{j}."
            sd_up_res_prefix = f"output_blocks.{3*i + j}.0."
            unet_conversion_map_layer.append((sd_up_res_prefix, hf_up_res_prefix))

            # if i > 0: commentout for sdxl
            # no attention layers in up_blocks.0
            hf_up_atn_prefix = f"up_blocks.{i}.attentions.{j}."
            sd_up_atn_prefix = f"output_blocks.{3*i + j}.1."
            unet_conversion_map_layer.append((sd_up_atn_prefix, hf_up_atn_prefix))

        if i < 3:
            # no downsample in down_blocks.3
            hf_downsample_prefix = f"down_blocks.{i}.downsamplers.0.conv."
            sd_downsample_prefix = f"input_blocks.{3*(i+1)}.0.op."
            unet_conversion_map_layer.append((sd_downsample_prefix, hf_downsample_prefix))

            # no upsample in up_blocks.3
            hf_upsample_prefix = f"up_blocks.{i}.upsamplers.0."
            sd_upsample_prefix = f"output_blocks.{3*i + 2}.{2}."  # change for sdxl
            unet_conversion_map_layer.append((sd_upsample_prefix, hf_upsample_prefix))

    hf_mid_atn_prefix = "mid_block.attentions.0."
    sd_mid_atn_prefix = "middle_block.1."
    unet_conversion_map_layer.append((sd_mid_atn_prefix, hf_mid_atn_prefix))

    for j in range(2):
        hf_mid_res_prefix = f"mid_block.resnets.{j}."
        sd_mid_res_prefix = f"middle_block.{2*j}."
        unet_conversion_map_layer.append((sd_mid_res_prefix, hf_mid_res_prefix))

    unet_conversion_map_resnet = [
        # (stable-diffusion, HF Diffusers)
        ("in_layers.0.", "norm1."),
        ("in_layers.2.", "conv1."),
        ("out_layers.0.", "norm2."),
        ("out_layers.3.", "conv2."),
        ("emb_layers.1.", "time_emb_proj."),
        ("skip_connection.", "conv_shortcut."),
    ]

    unet_conversion_map = []
    for sd, hf in unet_conversion_map_layer:
        if "resnets" in hf:
            for sd_res, hf_res in unet_conversion_map_resnet:
                unet_conversion_map.append((sd + sd_res, hf + hf_res))
        else:
            unet_conversion_map.append((sd, hf))

    for j in range(2):
        hf_time_embed_prefix = f"time_embedding.linear_{j+1}."
        sd_time_embed_prefix = f"time_embed.{j*2}."
        unet_conversion_map.append((sd_time_embed_prefix, hf_time_embed_prefix))

    for j in range(2):
        hf_label_embed_prefix = f"add_embedding.linear_{j+1}."
        sd_label_embed_prefix = f"label_emb.0.{j*2}."
        unet_conversion_map.append((sd_label_embed_prefix, hf_label_embed_prefix))

    unet_conversion_map.append(("input_blocks.0.0.", "conv_in."))
    unet_conversion_map.append(("out.0.", "conv_norm_out."))
    unet_conversion_map.append(("out.2.", "conv_out."))

    return unet_conversion_map


def convert_diffusers_unet_state_dict_to_sdxl(du_sd):
    unet_conversion_map = make_unet_conversion_map()

    conversion_map = {hf: sd for sd, hf in unet_conversion_map}
    return convert_unet_state_dict(du_sd, conversion_map)


def convert_unet_state_dict(src_sd, conversion_map):
    converted_sd = {}
    for src_key, value in src_sd.items():
        # さすがに全部回すのは時間がかかるので右から要素を削りつつprefixを探す
        src_key_fragments = src_key.split(".")[:-1]  # remove weight/bias
        while len(src_key_fragments) > 0:
            src_key_prefix = ".".join(src_key_fragments) + "."
            if src_key_prefix in conversion_map:
                converted_prefix = conversion_map[src_key_prefix]
                converted_key = converted_prefix + src_key[len(src_key_prefix) :]
                converted_sd[converted_key] = value
                break
            src_key_fragments.pop(-1)
        assert len(src_key_fragments) > 0, f"key {src_key} not found in conversion map"

    return converted_sd


def convert_sdxl_unet_state_dict_to_diffusers(sd):
    unet_conversion_map = make_unet_conversion_map()

    conversion_dict = {sd: hf for sd, hf in unet_conversion_map}
    return convert_unet_state_dict(sd, conversion_dict)


def convert_text_encoder_2_state_dict_to_sdxl(checkpoint, logit_scale):
    def convert_key(key):
        # position_idsの除去
        if ".position_ids" in key:
            return None

        # common
        key = key.replace("text_model.encoder.", "transformer.")
        key = key.replace("text_model.", "")
        if "layers" in key:
            # resblocks conversion
            key = key.replace(".layers.", ".resblocks.")
            if ".layer_norm" in key:
                key = key.replace(".layer_norm", ".ln_")
            elif ".mlp." in key:
                key = key.replace(".fc1.", ".c_fc.")
                key = key.replace(".fc2.", ".c_proj.")
            elif ".self_attn.out_proj" in key:
                key = key.replace(".self_attn.out_proj.", ".attn.out_proj.")
            elif ".self_attn." in key:
                key = None  # 特殊なので後で処理する
            else:
                raise ValueError(f"unexpected key in DiffUsers model: {key}")
        elif ".position_embedding" in key:
            key = key.replace("embeddings.position_embedding.weight", "positional_embedding")
        elif ".token_embedding" in key:
            key = key.replace("embeddings.token_embedding.weight", "token_embedding.weight")
        elif "text_projection" in key:  # no dot in key
            key = key.replace("text_projection.weight", "text_projection")
        elif "final_layer_norm" in key:
            key = key.replace("final_layer_norm", "ln_final")
        return key

    keys = list(checkpoint.keys())
    new_sd = {}
    for key in keys:
        new_key = convert_key(key)
        if new_key is None:
            continue
        new_sd[new_key] = checkpoint[key]

    # attnの変換
    for key in keys:
        if "layers" in key and "q_proj" in key:
            # 三つを結合
            key_q = key
            key_k = key.replace("q_proj", "k_proj")
            key_v = key.replace("q_proj", "v_proj")

            value_q = checkpoint[key_q]
            value_k = checkpoint[key_k]
            value_v = checkpoint[key_v]
            value = torch.cat([value_q, value_k, value_v])

            new_key = key.replace("text_model.encoder.layers.", "transformer.resblocks.")
            new_key = new_key.replace(".self_attn.q_proj.", ".attn.in_proj_")
            new_sd[new_key] = value

    if logit_scale is not None:
        new_sd["logit_scale"] = logit_scale

    return new_sd


def save_stable_diffusion_checkpoint(
    output_file,
    text_encoder1,
    text_encoder2,
    unet,
    epochs,
    steps,
    ckpt_info,
    vae,
    logit_scale,
    metadata,
    save_dtype=None,
):
    state_dict = {}

    def update_sd(prefix, sd):
        for k, v in sd.items():
            key = prefix + k
            if save_dtype is not None:
                v = v.detach().clone().to("cpu").to(save_dtype)
            state_dict[key] = v

    # Convert the UNet model
    update_sd("model.diffusion_model.", unet.state_dict())

    # Convert the text encoders
    update_sd("conditioner.embedders.0.transformer.", text_encoder1.state_dict())

    text_enc2_dict = convert_text_encoder_2_state_dict_to_sdxl(text_encoder2.state_dict(), logit_scale)
    update_sd("conditioner.embedders.1.model.", text_enc2_dict)

    # Convert the VAE
    vae_dict = model_util.convert_vae_state_dict(vae.state_dict())
    update_sd("first_stage_model.", vae_dict)

    # Put together new checkpoint
    key_count = len(state_dict.keys())
    new_ckpt = {"state_dict": state_dict}

    # epoch and global_step are sometimes not int
    if ckpt_info is not None:
        epochs += ckpt_info[0]
        steps += ckpt_info[1]

    new_ckpt["epoch"] = epochs
    new_ckpt["global_step"] = steps

    if model_util.is_safetensors(output_file):
        save_file(state_dict, output_file, metadata)
    else:
        torch.save(new_ckpt, output_file)

    return key_count


def save_diffusers_checkpoint(
    output_dir, text_encoder1, text_encoder2, unet, pretrained_model_name_or_path, vae=None, use_safetensors=False, save_dtype=None
):
    from diffusers import StableDiffusionXLPipeline

    # convert U-Net
    unet_sd = unet.state_dict()
    du_unet_sd = convert_sdxl_unet_state_dict_to_diffusers(unet_sd)

    diffusers_unet = UNet2DConditionModel(**DIFFUSERS_SDXL_UNET_CONFIG)
    if save_dtype is not None:
        diffusers_unet.to(save_dtype)
    diffusers_unet.load_state_dict(du_unet_sd)

    # create pipeline to save
    if pretrained_model_name_or_path is None:
        pretrained_model_name_or_path = DIFFUSERS_REF_MODEL_ID_SDXL

    scheduler = EulerDiscreteScheduler.from_pretrained(pretrained_model_name_or_path, subfolder="scheduler")
    tokenizer1 = CLIPTokenizer.from_pretrained(pretrained_model_name_or_path, subfolder="tokenizer")
    tokenizer2 = CLIPTokenizer.from_pretrained(pretrained_model_name_or_path, subfolder="tokenizer_2")
    if vae is None:
        vae = AutoencoderKL.from_pretrained(pretrained_model_name_or_path, subfolder="vae")

    # prevent local path from being saved
    def remove_name_or_path(model):
        if hasattr(model, "config"):
            model.config._name_or_path = None
            model.config._name_or_path = None

    remove_name_or_path(diffusers_unet)
    remove_name_or_path(text_encoder1)
    remove_name_or_path(text_encoder2)
    remove_name_or_path(scheduler)
    remove_name_or_path(tokenizer1)
    remove_name_or_path(tokenizer2)
    remove_name_or_path(vae)

    pipeline = StableDiffusionXLPipeline(
        unet=diffusers_unet,
        text_encoder=text_encoder1,
        text_encoder_2=text_encoder2,
        vae=vae,
        scheduler=scheduler,
        tokenizer=tokenizer1,
        tokenizer_2=tokenizer2,
    )
    if save_dtype is not None:
        pipeline.to(None, save_dtype)
    pipeline.save_pretrained(output_dir, safe_serialization=use_safetensors)