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ai-toolkit/extensions_built_in/diffusion_models/qwen_image/qwen_image.py
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2026-08-27 15:37:13 -06:00

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Python

import os
from typing import TYPE_CHECKING, List, Optional
import torch
import yaml
from toolkit import train_tools
from toolkit.config_modules import GenerateImageConfig, ModelConfig
from PIL import Image
from toolkit.models.base_model import BaseModel
from toolkit.models.v2.vae.qwen_image import QwenImageVAE, QwenImageVAEHolderMixin
from toolkit.basic import flush
from toolkit.prompt_utils import PromptEmbeds
from toolkit.samplers.custom_flowmatch_sampler import (
CustomFlowMatchEulerDiscreteScheduler,
)
from toolkit.accelerator import get_accelerator, unwrap_model
from toolkit.util.quantize import quantize_model
import torch.nn.functional as F
from toolkit.memory_management import MemoryManager
from toolkit.metadata import get_meta_for_safetensors
from safetensors.torch import load_file
from diffusers import (
QwenImagePipeline,
AutoencoderKLQwenImage,
)
from transformers import Qwen2VLProcessor
from toolkit.models.v2.diffusion_models.qwen_image import QwenImageTransformer2DModel
from toolkit.models.v2.text_encoders.qwen25_vl import Qwen25VLTextEncoder
from tqdm import tqdm
from toolkit.util.qwen_vae_gradient_checkpointing import patch_qwen_vae_gradient_checkpointing
patch_qwen_vae_gradient_checkpointing()
if TYPE_CHECKING:
from toolkit.data_transfer_object.data_loader import DataLoaderBatchDTO
scheduler_config = {
"base_image_seq_len": 256,
"base_shift": 0.5,
"invert_sigmas": False,
"max_image_seq_len": 8192,
"max_shift": 0.9,
"num_train_timesteps": 1000,
"shift": 1.0,
"shift_terminal": 0.02,
"stochastic_sampling": False,
"time_shift_type": "exponential",
"use_beta_sigmas": False,
"use_dynamic_shifting": True,
"use_exponential_sigmas": False,
"use_karras_sigmas": False,
}
class QwenImageModel(QwenImageVAEHolderMixin, BaseModel):
arch = "qwen_image"
_qwen_image_keep_visual = False
_qwen_pipeline = QwenImagePipeline
def __init__(
self,
device,
model_config: ModelConfig,
dtype="bf16",
custom_pipeline=None,
noise_scheduler=None,
**kwargs,
):
super().__init__(
device, model_config, dtype, custom_pipeline, noise_scheduler, **kwargs
)
self.is_flow_matching = True
self.is_transformer = True
self.target_lora_modules = ["QwenImageTransformer2DModel"]
# static method to get the noise scheduler
@staticmethod
def get_train_scheduler():
return CustomFlowMatchEulerDiscreteScheduler(**scheduler_config)
def get_bucket_divisibility(self):
return 16 * 2 # 16 for the VAE, 2 for patch size
def load_model(self):
dtype = self.torch_dtype
self.print_and_status_update("Loading Qwen Image model")
model_path = self.model_config.name_or_path
base_model_path = self.model_config.extras_name_or_path
model_dtype = dtype
if base_model_path.endswith(".safetensors"):
# use the repo for extras
base_model_path = "Qwen/Qwen-Image"
self.print_and_status_update("Loading transformer")
if not model_path.endswith(".safetensors") and os.path.exists(model_path):
# check if the path is a full checkpoint.
te_folder_path = os.path.join(model_path, "text_encoder")
# if we have the te, this folder is a full checkpoint, use it as the base
if os.path.exists(te_folder_path):
base_model_path = model_path
transformer = QwenImageTransformer2DModel.load_model(
model_path,
dtype=model_dtype,
use_comfy_weights=self.model_config.model_kwargs.get(
"use_comfy_weights", True
),
)
if self.model_config.quantize and not getattr(
transformer, "aitk_is_quantized", False
):
self.print_and_status_update("Quantizing Transformer")
quantize_model(self, transformer)
flush()
if (
self.model_config.layer_offloading
and self.model_config.layer_offloading_transformer_percent > 0
):
MemoryManager.attach(
transformer,
self.device_torch,
offload_percent=self.model_config.layer_offloading_transformer_percent,
)
if self.model_config.low_vram:
self.print_and_status_update("Moving transformer to CPU")
transformer.to("cpu")
flush()
self.print_and_status_update("Text Encoder")
tokenizer = Qwen25VLTextEncoder.load_tokenizer(base_model_path, use_fast=False)
text_encoder = Qwen25VLTextEncoder.load_model(base_model_path, dtype=dtype)
# remove the visual model as it is not needed for image generation
self.processor = None
if not self._qwen_image_keep_visual:
text_encoder.drop_vision_tower()
self.prepare_text_encoder(text_encoder, dtype=dtype)
self.print_and_status_update("Loading VAE")
vae = QwenImageVAE.load_model(base_model_path, dtype=dtype)
self.noise_scheduler = QwenImageModel.get_train_scheduler()
self.print_and_status_update("Making pipe")
kwargs = {}
if self._qwen_image_keep_visual:
try:
self.processor = Qwen2VLProcessor.from_pretrained(
model_path, subfolder="processor"
)
except OSError:
self.processor = Qwen2VLProcessor.from_pretrained(
base_model_path, subfolder="processor"
)
kwargs["processor"] = self.processor
pipe: QwenImagePipeline = self._qwen_pipeline(
scheduler=self.noise_scheduler,
text_encoder=None,
tokenizer=tokenizer,
vae=vae,
transformer=None,
**kwargs,
)
# for quantization, it works best to do these after making the pipe
pipe.text_encoder = text_encoder
pipe.transformer = transformer
self.print_and_status_update("Preparing Model")
text_encoder = [pipe.text_encoder]
tokenizer = [pipe.tokenizer]
# leave it on cpu for now
if not self.low_vram:
pipe.transformer = pipe.transformer.to(self.device_torch)
flush()
# just to make sure everything is on the right device and dtype
text_encoder[0].to(self.device_torch)
text_encoder[0].requires_grad_(False)
text_encoder[0].eval()
flush()
# save it to the model class
self.vae = vae
self.text_encoder = text_encoder # list of text encoders
self.tokenizer = tokenizer # list of tokenizers
self.model = pipe.transformer
self.pipeline = pipe
self.print_and_status_update("Model Loaded")
def get_generation_pipeline(self):
scheduler = QwenImageModel.get_train_scheduler()
pipeline: QwenImagePipeline = QwenImagePipeline(
scheduler=scheduler,
text_encoder=unwrap_model(self.text_encoder[0]),
tokenizer=self.tokenizer[0],
vae=unwrap_model(self.vae),
transformer=unwrap_model(self.transformer),
)
pipeline = pipeline.to(self.device_torch)
return pipeline
def generate_single_image(
self,
pipeline: QwenImagePipeline,
gen_config: GenerateImageConfig,
conditional_embeds: PromptEmbeds,
unconditional_embeds: PromptEmbeds,
generator: torch.Generator,
extra: dict,
):
self.model.to(self.device_torch, dtype=self.torch_dtype)
control_img = None
if gen_config.ctrl_img is not None:
raise NotImplementedError(
"Control image generation is not supported in Qwen Image model... yet"
)
control_img = Image.open(gen_config.ctrl_img)
control_img = control_img.convert("RGB")
# resize to width and height
if control_img.size != (gen_config.width, gen_config.height):
control_img = control_img.resize(
(gen_config.width, gen_config.height), Image.BILINEAR
)
self.model.to(self.device_torch)
# flush for low vram if we are doing that
flush_between_steps = self.model_config.low_vram
# Fix a bug in diffusers/torch
def callback_on_step_end(pipe, i, t, callback_kwargs):
if flush_between_steps:
flush()
latents = callback_kwargs["latents"]
return {"latents": latents}
sc = self.get_bucket_divisibility()
gen_config.width = int(gen_config.width // sc * sc)
gen_config.height = int(gen_config.height // sc * sc)
if self.model_config.low_vram:
# set vae to tile decode
pipeline.vae.enable_tiling()
img = pipeline(
prompt_embeds=conditional_embeds.text_embeds,
prompt_embeds_mask=conditional_embeds.attention_mask.to(
self.device_torch, dtype=torch.int64
),
negative_prompt_embeds=unconditional_embeds.text_embeds,
negative_prompt_embeds_mask=unconditional_embeds.attention_mask.to(
self.device_torch, dtype=torch.int64
),
height=gen_config.height,
width=gen_config.width,
num_inference_steps=gen_config.num_inference_steps,
true_cfg_scale=gen_config.guidance_scale,
latents=gen_config.latents,
generator=generator,
callback_on_step_end=callback_on_step_end,
**extra,
).images[0]
if self.model_config.low_vram:
# restore no tiling
pipeline.vae.disable_tiling()
return img
def get_noise_prediction(
self,
latent_model_input: torch.Tensor,
timestep: torch.Tensor, # 0 to 1000 scale
text_embeddings: PromptEmbeds,
**kwargs,
):
self.model.to(self.device_torch)
batch_size, num_channels_latents, height, width = latent_model_input.shape
ps = self.transformer.config.patch_size
# pack image tokens
latent_model_input = latent_model_input.view(
batch_size, num_channels_latents, height // ps, ps, width // ps, ps
)
latent_model_input = latent_model_input.permute(0, 2, 4, 1, 3, 5)
latent_model_input = latent_model_input.reshape(
batch_size, (height // ps) * (width // ps), num_channels_latents * (ps * ps)
)
# img_shapes passed to the model
img_h2, img_w2 = height // ps, width // ps
img_shapes = [[(1, img_h2, img_w2)]] * batch_size
enc_hs = text_embeddings.text_embeds.to(self.device_torch, self.torch_dtype)
prompt_embeds_mask = text_embeddings.attention_mask.to(
self.device_torch, dtype=torch.int64
)
noise_pred = self.transformer(
hidden_states=latent_model_input.to(
self.device_torch, self.torch_dtype
).detach(),
timestep=(timestep / 1000).detach(),
guidance=None,
encoder_hidden_states=enc_hs.detach(),
encoder_hidden_states_mask=prompt_embeds_mask.detach(),
img_shapes=img_shapes,
return_dict=False,
**kwargs,
)[0]
# unpack
noise_pred = noise_pred.view(
batch_size, height // ps, width // ps, num_channels_latents, ps, ps
)
noise_pred = noise_pred.permute(0, 3, 1, 4, 2, 5)
noise_pred = noise_pred.reshape(batch_size, num_channels_latents, height, width)
return noise_pred
def get_prompt_embeds(self, prompt: str) -> PromptEmbeds:
if self.pipeline.text_encoder.device != self.device_torch:
self.pipeline.text_encoder.to(self.device_torch)
prompt_embeds, prompt_embeds_mask = self.pipeline.encode_prompt(
prompt,
device=self.device_torch,
num_images_per_prompt=1,
)
# diffusers >=0.37 returns None when all tokens are valid (no padding)
if prompt_embeds_mask is None:
prompt_embeds_mask = torch.ones(
prompt_embeds.shape[:2], device=prompt_embeds.device, dtype=torch.int64
)
pe = PromptEmbeds(prompt_embeds)
pe.attention_mask = prompt_embeds_mask
return pe
def get_model_has_grad(self):
return False
def get_te_has_grad(self):
return False
def save_model(self, output_path, meta, save_dtype):
# comfy-format single-file save (diffusers keys ARE the comfy layout
# for qwen image); prequantized layers keep their quantized storage
transformer: QwenImageTransformer2DModel = unwrap_model(self.model)
if not output_path.endswith(".safetensors"):
output_path += ".safetensors"
transformer.save_model(
output_path,
dtype=save_dtype,
metadata=get_meta_for_safetensors(meta, name=self.arch),
)
def get_loss_target(self, *args, **kwargs):
noise = kwargs.get("noise")
batch = kwargs.get("batch")
return (noise - batch.latents).detach()
def get_base_model_version(self):
return "qwen_image"
def get_transformer_block_names(self) -> Optional[List[str]]:
return ["transformer_blocks"]
lora_keys_use_comfy_prefix = True