app.py

from langchain.document_loaders import PyPDFDirectoryLoader

loader = PyPDFDirectoryLoader("./data")
docs = loader.load()

from langchain.text_splitter import RecursiveCharacterTextSplitter

text_splitter = RecursiveCharacterTextSplitter(
    chunk_size = 100, 
    chunk_overlap  = 20, 
    length_function = len, 
)

documents = text_splitter.split_documents(docs)

import os
os.environ["OPENAI_API_KEY"] = "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"

from langchain.embeddings.openai import OpenAIEmbeddings
embeddings = OpenAIEmbeddings() 

from langchain.vectorstores import Chroma
persist_directory = "vector_db"
vectordb = Chroma.from_documents(docs, embedding = embeddings, persist_directory=persist_directory)

vectordb.persist()
vectordb = None

# As you can see when you run the following cell - 
# loaded the persisted vectore store is much quicker than reinstantiating it - 
# and that is the benefit of persist_directory!
vectordb = Chroma(persist_directory=persist_directory, embedding_function=embeddings)

# Bring up ChatOpenAI
from langchain.chat_models import ChatOpenAI
llm = ChatOpenAI(model_name = "gpt-3.5-turbo")

# Set up the document vector store as a Retriever tool
doc_retriever = vectordb.as_retriever()

# Now setup the RetrievalQA chain and leverage all the documents in the Vector DB
from langchain.chains import RetrievalQA
EN_17272_qa = RetrievalQA.from_chain_type(llm, chain_type="stuff", retriever=doc_retriever)

def make_answer(query):
    return EN_17272_qa.run(query)

if __name__ == "__main__":
    # make a gradio intgerface
    import gradio as gr

    gr.Interface(
        make_answer,
        [gr.inputs.Textbox(lines=2, label="Input a question")],
        gr.outputs.Textbox(labels="Answer"),
        title="EN-17272 & Efficacy Reports",
        descriptions="EN-17272 & Efficacy reports is a generative model that gives answers based on the documents",
    ).launch()