app.py

import torch

# Enable faster matrix math on CUDA
torch.backends.cuda.matmul.allow_tf32 = True
torch.backends.cudnn.allow_tf32 = True

import os
import gradio as gr
import spaces

from diffusers import FlowMatchEulerDiscreteScheduler
from lakonlab.ui.gradio.create_text_to_img import create_interface_text_to_img
from lakonlab.pipelines.piqwen_pipeline import PiQwenImagePipeline
from huggingface_hub import login

#############3
import math


# Authenticate with Hugging Face. The token should be supplied via the
# `HF_TOKEN` environment variable to avoid hard‑coding credentials.
login(token=os.getenv('HF_TOKEN'))

# Default prompt used when the demo launches. The prompt mirrors the example
# provided in the original π‑Qwen demo.
DEFAULT_PROMPT = (
    'Photo of a coffee shop entrance featuring a chalkboard sign reading "π‑Qwen Coffee $2 per cup," '
    'with a neon light beside it displaying "π‑通义千问". Next to it hangs a poster showing a beautiful '
    'Chinese woman, and beneath the poster is written "e≈2.71828-18284-59045-23536-02874-71352".'
)

# -----------------------------------------------------------------------------
# Model and adapter loading
#
# We first construct a PiQwenImagePipeline using the base Qwen/Qwen‑Image
# checkpoint. Then we load the π‑Flow adapter from Lakonik/pi‑Qwen‑Image to
# enable few‑step generation. Finally, we load an additional LoRA from the
# user's Hugging Face repository and activate both adapters simultaneously.
# -----------------------------------------------------------------------------

pipe = PiQwenImagePipeline.from_pretrained(
    'Qwen/Qwen-Image',
    torch_dtype=torch.bfloat16)


adapter_name = pipe.load_piflow_adapter(
    'Lakonik/pi-Qwen-Image',
    subfolder='gmqwen_k8_piid_4step',
    target_module_name='transformer')

print("Adapter name:", adapter_name)
print("Tiene atributo transformer_piflow?", hasattr(pipe, "transformer_piflow"))

pipe.transformer.load_lora_adapter(
    'lichorosario/dott-qwen-image-lora',
    weight_name='dott-3000-qwen-image.safetensors',
    adapter_name='dott',
    prefix="diffusion_model"
)


pipe.set_adapters([adapter_name, 'dott'], adapter_weights=[1.0, 1.0])

pipe.scheduler = FlowMatchEulerDiscreteScheduler.from_config(  # use fixed shift=3.2
    pipe.scheduler.config, 
    #shift=3.2, 
    #shift_terminal=None, 
    # use_dynamic_shifting=True,
############################################
    base_image_seq_len = 256,
    base_shift = math.log(3),
    invert_sigmas = False,
    max_image_seq_len = 8192,
    max_shift = math.log(3),
    num_train_timesteps = 1000,
    shift = 1.0,
    shift_terminal = None,
    stochastic_sampling = False,
    time_shift_type = "exponential",
    use_beta_sigmas = False,
    use_dynamic_shifting = True,
    use_exponential_sigmas = False,
    use_karras_sigmas = False,

)

pipe = pipe.to('cuda')

# -----------------------------------------------------------------------------
# Gradio interface
#
# The `generate` function takes the usual generation parameters (seed, prompt,
# width, height and number of steps) and returns a single PIL image. The
# `@spaces.GPU` decorator indicates to the Spaces runtime that this function
# should execute on GPU. The progress bar from `gr.Progress` is optional but
# improves user experience during longer runs.
# -----------------------------------------------------------------------------

@spaces.GPU
def generate(seed, prompt, width, height, steps, progress=gr.Progress(track_tqdm=True)):
    """Generate an image using the π‑Qwen pipeline with both the π‑Flow adapter
    and the user's custom LoRA active."""
    return pipe(
        prompt=prompt,
        width=width,
        height=height,
        num_inference_steps=steps,
        generator=torch.Generator().manual_seed(seed),
    ).images[0]


with gr.Blocks(
    analytics_enabled=False,
    title='pi‑Qwen Demo with Custom LoRA',
    css='lakonlab/ui/gradio/style.css'
) as demo:
    # Markdown description explaining the purpose of this demo. Note the added
    # description of the custom LoRA. Feel free to edit this text to better
    # describe your use case.
    md_txt = (
        '# pi‑Qwen Demo with Custom LoRA\n\n'
        'This demo showcases the [pi‑Flow: Policy‑Based Few‑Step Generation via Imitation '
        'Distillation](https://arxiv.org/abs/2510.14974) technique applied to '
        'the Qwen‑Image base model. In addition to the fast π‑Flow policy, this '
        'version also loads a user‑provided LoRA from '
        '`lichorosario/dott‑3000‑qwen‑image‑lora` to stylize the outputs.\n\n'
        '**Base model:** [Qwen‑Image](https://huggingface.co/Qwen/Qwen-Image). '
        '**Fast policy:** GMFlow. **Code:** '
        '[https://github.com/Lakonik/piFlow](https://github.com/Lakonik/piFlow).'
    )
    gr.Markdown(md_txt)
    # Create the text‑to‑image interface using the helper from the LakonLab
    # library. We expose the seed, prompt, width, height and steps arguments.
    create_interface_text_to_img(
        generate,
        prompt=DEFAULT_PROMPT,
        steps=4,
        guidance_scale=None,
        args=['last_seed', 'prompt', 'width', 'height', 'steps']
    )
    # Launch the app. In a Gradio Space this call is optional, but including
    # it allows the script to be run locally as well.
    demo.queue().launch()