DFloat11 / Qwen-Image-DF11

DFloat11 Compressed Model: Qwen/Qwen-Image

This is a DFloat11 losslessly compressed version of the original Qwen/Qwen-Image model. It reduces model size by 32% compared to the original BFloat16 model, while maintaining bit-identical outputs and supporting efficient GPU inference .

🔥🔥🔥 Thanks to DFloat11 compression, Qwen-Image can now run on a single 32GB GPU , or on a single 16GB GPU with CPU offloading , while maintaining full model quality. 🔥🔥🔥

📊 Performance Comparison

🔧 How to Use

1. Install or upgrade the DFloat11 pip package (installs the CUDA kernel automatically; requires a CUDA-compatible GPU and PyTorch installed) :

   pip install -U dfloat11[cuda12]
   

2. Install or upgrade diffusers:

   pip install git+https://github.com/huggingface/diffusers
   

3. Save the following code to a Python file qwen_image.py :

   from diffusers import DiffusionPipeline, QwenImageTransformer2DModel
   import torch
   from transformers.modeling_utils import no_init_weights
   from dfloat11 import DFloat11Model
   import argparse
   
   def parse_args():
       parser = argparse.ArgumentParser(description='Generate images using Qwen-Image model')
       parser.add_argument('--cpu_offload', action='store_true', help='Enable CPU offloading')
       parser.add_argument('--prompt', type=str, default='A coffee shop entrance features a chalkboard sign reading "Qwen Coffee 😊 $2 per cup," with a neon light beside it displaying "通义千问". Next to it hangs a poster showing a beautiful Chinese woman, and beneath the poster is written "π≈3.1415926-53589793-23846264-33832795-02384197".',
                           help='Text prompt for image generation')
       parser.add_argument('--negative_prompt', type=str, default=' ',
                           help='Negative prompt for image generation')
       parser.add_argument('--aspect_ratio', type=str, default='16:9', choices=['1:1', '16:9', '9:16', '4:3', '3:4'],
                           help='Aspect ratio of generated image')
       parser.add_argument('--num_inference_steps', type=int, default=50,
                           help='Number of denoising steps')
       parser.add_argument('--true_cfg_scale', type=float, default=4.0,
                           help='Classifier free guidance scale')
       parser.add_argument('--seed', type=int, default=42,
                           help='Random seed for generation')
       parser.add_argument('--output', type=str, default='example.png',
                           help='Output image path')
       parser.add_argument('--language', type=str, default='en', choices=['en', 'zh'],
                           help='Language for positive magic prompt')
       return parser.parse_args()
   
   args = parse_args()
   
   model_name = "Qwen/Qwen-Image"
   
   with no_init_weights():
       transformer = QwenImageTransformer2DModel.from_config(
           QwenImageTransformer2DModel.load_config(
               model_name, subfolder="transformer",
           ),
       ).to(torch.bfloat16)
   
   DFloat11Model.from_pretrained(
       "DFloat11/Qwen-Image-DF11",
       device="cpu",
       cpu_offload=args.cpu_offload,
       bfloat16_model=transformer,
   )
   
   pipe = DiffusionPipeline.from_pretrained(
       model_name,
       transformer=transformer,
       torch_dtype=torch.bfloat16,
   )
   pipe.enable_model_cpu_offload()
   
   positive_magic = {
       "en": "Ultra HD, 4K, cinematic composition.", # for english prompt,
       "zh": "超清，4K，电影级构图" # for chinese prompt,
   }
   
   # Generate with different aspect ratios
   aspect_ratios = {
       "1:1": (1328, 1328),
       "16:9": (1664, 928),
       "9:16": (928, 1664),
       "4:3": (1472, 1140),
       "3:4": (1140, 1472),
   }
   
   width, height = aspect_ratios[args.aspect_ratio]
   
   image = pipe(
       prompt=args.prompt + positive_magic[args.language],
       negative_prompt=args.negative_prompt,
       width=width,
       height=height,
       num_inference_steps=args.num_inference_steps,
       true_cfg_scale=args.true_cfg_scale,
       generator=torch.Generator(device="cuda").manual_seed(args.seed)
   ).images[0]
   
   image.save(args.output)
   
   max_memory = torch.cuda.max_memory_allocated()
   print(f"Max memory: {max_memory / (1000 ** 3):.2f} GB")
   

4. To run without CPU offloading (32GB VRAM required):

   python qwen_image.py
   

   To run with CPU offloading (16GB VRAM required):

   python qwen_image.py --cpu_offload
   

🔍 How It Works

We apply Huffman coding to losslessly compress the exponent bits of BFloat16 model weights, which are highly compressible (their 8 bits carry only ~2.6 bits of actual information). To enable fast inference, we implement a highly efficient CUDA kernel that performs on-the-fly weight decompression directly on the GPU.

The result is a model that is ~32% smaller , delivers bit-identical outputs , and achieves performance comparable to the original BFloat16 model.

Learn more in our research paper .

📄 Learn More

• Paper : 70% Size, 100% Accuracy: Lossless LLM Compression for Efficient GPU Inference via Dynamic-Length Float
• GitHub : https://github.com/LeanModels/DFloat11
• HuggingFace : https://huggingface.co/DFloat11