app.py

import os
import warnings

# Ensure no GPU is used by setting the environment variable
# os.environ['CUDA_VISIBLE_DEVICES'] = '-1'

# Disable ZeroGPU if running in Hugging Face's environment
# os.environ["HF_USE_ZeroGPU"] = "false"

# Suppress NVML initialization warning
warnings.filterwarnings("ignore", message="Can't initialize NVML")

import gradio as gr
from langchain.embeddings import HuggingFaceEmbeddings
from langchain.vectorstores import Chroma
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.docstore.document import Document
from langchain.llms import HuggingFacePipeline
from langchain.chains import RetrievalQA
from transformers import AutoConfig, AutoTokenizer, pipeline, AutoModelForCausalLM
import torch
import re
import transformers
from torch import bfloat16
from langchain_community.document_loaders import DirectoryLoader
import spaces

# Initialize embeddings and ChromaDB
model_name = "sentence-transformers/all-mpnet-base-v2"
device = "cuda" if torch.cuda.is_available() else "cpu"
model_kwargs = {"device": device}
embeddings = HuggingFaceEmbeddings(model_name=model_name, model_kwargs=model_kwargs)

# loader = DirectoryLoader('./pdf', glob="**/*.pdf", use_multithreading=True)
loader = DirectoryLoader('./pdf', glob="**/*.pdf", recursive=True, use_multithreading=True)
docs = loader.load()
text_splitter = RecursiveCharacterTextSplitter(chunk_size=1000, chunk_overlap=200)
all_splits = text_splitter.split_documents(docs)
vectordb = Chroma.from_documents(documents=all_splits, embedding=embeddings, persist_directory="pdf_db")
books_db = Chroma(persist_directory="./pdf_db", embedding_function=embeddings)

books_db_client = books_db.as_retriever()

# Initialize the model and tokenizer
model_name = "unsloth/Llama-3.2-3B-Instruct"

# bnb_config = transformers.BitsAndBytesConfig(
#     load_in_4bit=True,
#     bnb_4bit_quant_type='nf4',
#     bnb_4bit_use_double_quant=True,
#     bnb_4bit_compute_dtype=torch.bfloat16
# )

model_config = transformers.AutoConfig.from_pretrained(model_name, max_new_tokens=1024)


model = transformers.AutoModelForCausalLM.from_pretrained(
    model_name,
    trust_remote_code=True,
    config=model_config,
    # quantization_config=bnb_config,
    device_map="auto" if device == "cuda" else None,
)


tokenizer = AutoTokenizer.from_pretrained(model_name)

query_pipeline = transformers.pipeline(
    "text-generation",
    model=model,
    tokenizer=tokenizer,
    return_full_text=True,
    torch_dtype=torch.float16 if device == "cuda" else torch.float32,
    device_map="auto" if device == "cuda" else None,
    temperature=0.3,  
    top_p=0.8,      
    top_k=50,        
    repetition_penalty=1.2,  
    max_new_tokens=128
)


llm = HuggingFacePipeline(pipeline=query_pipeline)

books_db_client_retriever = RetrievalQA.from_chain_type(
    llm=llm,
    chain_type="stuff",
    retriever=books_db_client,
    verbose=True
)

# Function to retrieve answer using the RAG system
@spaces.GPU(duration=60)
def test_rag(query):
    rag_query = f"You are an AI assistant with access to a knowledge base containing books and other materials. {query} Summarize the retrieved answer for this query. Retrieve information only from the provided knowledge base. If no relevant information is found in the knowledge base, do not provide placeholder answers. Respond only with clear and concise answers based on the available knowledge."
    books_retriever = books_db_client_retriever.run(rag_query)
    corrected_text_match = re.search(r"Helpful Answer:(.*)", books_retriever, re.DOTALL)
    if corrected_text_match:
        return corrected_text_match.group(1).strip()
    else:
        return "No helpful answer found."

# Gradio interface
def respond(message, history):
    response = test_rag(message)
    return response

iface = gr.ChatInterface(
    respond,
    chatbot=gr.Chatbot(height=700),
    textbox=gr.Textbox(placeholder="Ask me anything about the content of the PDF(s):", container=False, scale=7),
    title="RAG Chatbot",
    cache_examples=True,
)

iface.launch()