app.py

import spaces
import gradio as gr
from transformers import AutoModelForCausalLM, AutoTokenizer, TextIteratorStreamer, BitsAndBytesConfig
from accelerate import init_empty_weights, load_checkpoint_and_dispatch
import torch
from threading import Thread

# Model and device configuration
phi4_model_path = "Compumacy/OpenBioLLm-70B"
device = "cuda:0" if torch.cuda.is_available() else "cpu"

# === INITIALIZE EMPTY WEIGHTS ===
init_empty_weights()

# === CONFIGURE 4-BIT QUANTIZATION ===
bnb_config = BitsAndBytesConfig(
    load_in_4bit=True,
    bnb_4bit_compute_dtype=torch.float16,
    bnb_4bit_use_double_quant=True,
    bnb_4bit_quant_type="nf4"
)

# === LOAD MODEL WITH QUANTIZATION ===
model = AutoModelForCausalLM.from_pretrained(
    phi4_model_path,
    quantization_config=bnb_config,
    torch_dtype=torch.float16,
    device_map="auto"
)

tokenizer = AutoTokenizer.from_pretrained(phi4_model_path)

# === OFFLOAD TO CPU/DISK ===
model = load_checkpoint_and_dispatch(
    model,
    phi4_model_path,
    device_map="auto",
    offload_folder="offload",
    offload_state_dict=True,
    max_memory={**{i: "12GB" for i in range(torch.cuda.device_count())}, "cpu": "30GB"}
)

# Enable gradient checkpointing if ever fine-tuning
model.gradient_checkpointing_enable()

# Optionally compile for PyTorch >= 2.0
try:
    model = torch.compile(model)
except Exception:
    pass

# === RESPONSE GENERATOR ===
@spaces.GPU()
def generate_response(user_message, max_tokens, temperature, top_k, top_p, repetition_penalty, history_state):
    if not user_message.strip():
        return history_state, history_state

    # Prompt setup
    system_message = (
        "Your role as an assistant involves thoroughly exploring questions through a systematic thinking process..."
    )
    start_tag, sep_tag, end_tag = "<|im_start|>", "<|im_sep|>", "<|im_end|>"
    prompt = f"{start_tag}system{sep_tag}{system_message}{end_tag}"
    for msg in history_state:
        tag = msg["role"]
        content = msg["content"]
        prompt += f"{start_tag}{tag}{sep_tag}{content}{end_tag}"
    prompt += f"{start_tag}user{sep_tag}{user_message}{end_tag}{start_tag}assistant{sep_tag}"

    inputs = tokenizer(prompt, return_tensors="pt").to(device)

    # Streaming setup
    streamer = TextIteratorStreamer(tokenizer, skip_prompt=True)
    generation_kwargs = {
        "input_ids": inputs.input_ids,
        "attention_mask": inputs.attention_mask,
        "max_new_tokens": int(max_tokens),
        "do_sample": True,
        "temperature": temperature,
        "top_k": int(top_k),
        "top_p": top_p,
        "repetition_penalty": repetition_penalty,
        "streamer": streamer
    }

    # Run generation in thread
    Thread(target=model.generate, kwargs=generation_kwargs).start()

    assistant_response = ""
    new_history = history_state + [
        {"role": "user", "content": user_message},
        {"role": "assistant", "content": ""}
    ]

    # Stream tokens
    for token in streamer:
        clean = token.replace(start_tag, "").replace(sep_tag, "").replace(end_tag, "")
        assistant_response += clean
        new_history[-1]["content"] = assistant_response
        yield new_history, new_history

    yield new_history, new_history

# === EXAMPLE MESSAGES ===
example_messages = {
    "Math reasoning": "If a rectangular prism has a length of 6 cm...",
    "Logic puzzle": "Four people (Alex, Blake, Casey, ...)",
    "Physics problem": "A ball is thrown upward with an initial velocity..."
}

# === GRADIO APP ===
with gr.Blocks(theme=gr.themes.Soft()) as demo:
    gr.Markdown("""
    # Phi-4 Chat
    Try the example problems below to see how the model breaks down complex reasoning.
    """ )

    history_state = gr.State([])
    with gr.Row():
        with gr.Column(scale=1):
            gr.Markdown("### Settings")
            max_tokens_slider = gr.Slider(64, 32768, step=1024, value=2048, label="Max Tokens")
            with gr.Accordion("Advanced Settings", open=False):
                temperature_slider = gr.Slider(0.1, 2.0, value=0.8, label="Temperature")
                top_k_slider = gr.Slider(1, 100, step=1, value=50, label="Top-k")
                top_p_slider = gr.Slider(0.1, 1.0, value=0.95, label="Top-p")
                repetition_penalty_slider = gr.Slider(1.0, 2.0, value=1.0, label="Repetition Penalty")
        with gr.Column(scale=4):
            chatbot = gr.Chatbot(label="Chat", type="messages")
            with gr.Row():
                user_input = gr.Textbox(placeholder="Type your message...", scale=3)
                submit_button = gr.Button("Send", variant="primary", scale=1)
                clear_button = gr.Button("Clear", scale=1)
            gr.Markdown("**Try these examples:**")
            with gr.Row():
                for name in example_messages:
                    btn = gr.Button(name)
                    btn.click(fn=lambda n=name: gr.update(value=example_messages[n]), inputs=None, outputs=user_input)

    submit_button.click(
        fn=generate_response,
        inputs=[user_input, max_tokens_slider, temperature_slider, top_k_slider, top_p_slider, repetition_penalty_slider, history_state],
        outputs=[chatbot, history_state]
    ).then(lambda: gr.update(value=""), None, user_input)

    clear_button.click(lambda: ([], []), None, [chatbot, history_state])

demo.launch(ssr_mode=False)