PyCoder / app.py
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Gradio Python coder using the fine-tuned Qwen2.5-0.5B LoRA (#1)
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import threading
import gradio as gr
import torch
from peft import PeftModel
from transformers import AutoModelForCausalLM, AutoTokenizer, TextIteratorStreamer
BASE_MODEL = "Qwen/Qwen2.5-0.5B-Instruct"
ADAPTER = "ali4566544/qwen2.5-0.5b-instruct-python-lora"
# The adapter was trained with this exact system prompt.
SYSTEM_PROMPT = (
"You are a helpful Python coding assistant. Write clear, correct, idiomatic Python, "
"explain the code concisely, and point out bugs and how to fix them when asked."
)
tokenizer = AutoTokenizer.from_pretrained(ADAPTER)
base = AutoModelForCausalLM.from_pretrained(BASE_MODEL, torch_dtype=torch.float32)
# Merge LoRA weights into the base model for faster CPU inference.
model = PeftModel.from_pretrained(base, ADAPTER).merge_and_unload()
model.eval()
def respond(message, history, max_new_tokens, temperature):
messages = [{"role": "system", "content": SYSTEM_PROMPT}]
messages += [{"role": m["role"], "content": m["content"]} for m in history]
messages.append({"role": "user", "content": message})
inputs = tokenizer.apply_chat_template(
messages, add_generation_prompt=True, return_tensors="pt", return_dict=True
)
streamer = TextIteratorStreamer(tokenizer, skip_prompt=True, skip_special_tokens=True)
gen_kwargs = dict(**inputs, streamer=streamer, max_new_tokens=int(max_new_tokens))
if temperature > 0:
gen_kwargs.update(do_sample=True, temperature=temperature, top_p=0.9)
else:
gen_kwargs.update(do_sample=False)
threading.Thread(target=model.generate, kwargs=gen_kwargs).start()
output = ""
for chunk in streamer:
output += chunk
yield output
demo = gr.ChatInterface(
respond,
type="messages",
title="🐍 PyCoder",
description=(
"A small Python coding assistant: Qwen2.5-0.5B-Instruct fine-tuned with a "
f"[LoRA adapter](https://huggingface.co/{ADAPTER}). It's a 0.5B learning project, "
"so always run and test the code it writes."
),
additional_inputs=[
gr.Slider(64, 1024, value=512, step=32, label="Max new tokens"),
gr.Slider(0.0, 1.5, value=0.0, step=0.1, label="Temperature (0 = greedy)"),
],
examples=[
["Write a function that removes duplicates from a list while keeping order."],
["How do I read a CSV file with pandas and drop rows with missing values?"],
["Write a minimal FastAPI app with a /health endpoint."],
["Why does this fail? `for i in range(len(xs)): xs.remove(xs[i])`"],
],
cache_examples=False,
)
if __name__ == "__main__":
demo.launch()