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from langchain.retrievers.multi_query import MultiQueryRetriever |
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from langchain_openai import ChatOpenAI |
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from langchain_community.document_transformers import LongContextReorder |
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from langchain_text_splitters import RecursiveCharacterTextSplitter |
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from langchain.schema import Document |
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from langchain_chroma import Chroma |
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from langchain_openai import OpenAIEmbeddings |
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from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder |
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from langchain.chains import create_retrieval_chain |
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from langchain.chains.combine_documents import create_stuff_documents_chain |
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from langchain_core.messages import HumanMessage |
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def generate_response(input, history): |
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vector_db = Chroma(persist_directory="vector_db", embedding_function=OpenAIEmbeddings()) |
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retriever = vector_db.as_retriever( |
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search_type="similarity_score_threshold", search_kwargs={"score_threshold": 0.7, "k": 10} |
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) |
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llm = ChatOpenAI(model="gpt-4o-mini", temperature=0.2) |
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retriever = MultiQueryRetriever.from_llm( |
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retriever=retriever, llm=llm |
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) |
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unique_docs = retriever.invoke(input) |
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reordering = LongContextReorder() |
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reordered_docs = reordering.transform_documents(unique_docs) |
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SYSTEM_TEMPLATE = """ |
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Answer the user's questions based on the below context. |
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The context will always be relevant to the question. |
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Use chat history if required to answer the question. |
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Always be very descriptive, unless stated otherwise. |
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Explain as if you are a master at this subject. |
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<context> |
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{context} |
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</context> |
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<chat_history> |
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{chat_history} |
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</chat_history> |
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""" |
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question_answering_prompt = ChatPromptTemplate.from_messages( |
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[ |
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( |
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"system", |
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SYSTEM_TEMPLATE, |
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), |
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MessagesPlaceholder(variable_name="messages"), |
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] |
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) |
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document_chain = create_stuff_documents_chain(llm, question_answering_prompt) |
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reponse = document_chain.invoke( |
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{ |
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"context": reordered_docs, |
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"messages": [ |
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HumanMessage(content=input) |
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], |
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"chat_history": history |
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} |
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) |
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return reponse |
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if __name__ == "__main__": |
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prompt = "How should my MDPE pipe cross a Nallah?" |
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response = generate_response(prompt) |
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print(response) |
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