app.py

import pathlib

import gradio as gr
import torch
from scipy.special import softmax
from transformers import AutoTokenizer, AutoModelForSequenceClassification

# load model
MODEL_PATH = pathlib.Path("data") / "roberta-large-wmt"

tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH)
model = AutoModelForSequenceClassification.from_pretrained(MODEL_PATH)

model.to("cuda" if torch.cuda.is_available() else "cpu")


def detect(text: str) -> str:
    inputs = tokenizer(text, return_tensors="pt")
    with torch.no_grad():
        logits = model(**inputs).logits
    predicted_class_id = logits.argmax(dim=1).item()

    label = model.config.id2label[predicted_class_id]

    result = "machine-generated" if label == "0" else "human-generated"

    return ", ".join(
        [
            f"The text is {result}",
            f"with a certainty of ${100 * softmax(logits, axis=1)[0][int(label)]:.2f}%",
        ]
    )


with gr.Blocks() as demo:
    gr.Markdown(
        """
        # Hello!
        This is the demo for <a href="https://arxiv.org/abs/2305.12680" target="_blank">G3Detector</a>.
        """
    )
    inp = gr.Textbox(label="Text", placeholder="Paste text here...")
    out = gr.Textbox(label="Result")
    detect_btn = gr.Button("Detect")
    detect_btn.click(fn=detect, inputs=inp, outputs=out, api_name="G3Detector")

demo.launch()