langchain/docs/examples/chains/qa_with_sources.ipynb

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  {
   "cell_type": "markdown",
   "id": "74148cee",
   "metadata": {},
   "source": [
    "# Question Answering with Sources\n",
    "\n",
    "This notebook walks through how to use LangChain for question answering with sources over a list of documents. It covers three different chain types: `stuff`, `map_reduce`, and `refine`. For a more in depth explanation of what these chain types are, see [here](../../explanation/combine_docs.md)."
   ]
  },
  {
   "cell_type": "markdown",
   "id": "ca2f0efc",
   "metadata": {},
   "source": [
    "### Prepare Data\n",
    "First we prepare the data. For this example we do similarity search over a vector database, but these documents could be fetched in any manner (the point of this notebook to highlight what to do AFTER you fetch the documents)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "78f28130",
   "metadata": {},
   "outputs": [],
   "source": [
    "from langchain.embeddings.openai import OpenAIEmbeddings\n",
    "from langchain.embeddings.cohere import CohereEmbeddings\n",
    "from langchain.text_splitter import CharacterTextSplitter\n",
    "from langchain.vectorstores.elastic_vector_search import ElasticVectorSearch\n",
    "from langchain.vectorstores.faiss import FAISS\n",
    "from langchain.docstore.document import Document"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "4da195a3",
   "metadata": {},
   "outputs": [],
   "source": [
    "with open('../state_of_the_union.txt') as f:\n",
    "    state_of_the_union = f.read()\n",
    "text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)\n",
    "texts = text_splitter.split_text(state_of_the_union)\n",
    "\n",
    "embeddings = OpenAIEmbeddings()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "5ec2b55b",
   "metadata": {},
   "outputs": [],
   "source": [
    "docsearch = FAISS.from_texts(texts, embeddings, metadatas=[{\"source\": i} for i in range(len(texts))])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "5286f58f",
   "metadata": {},
   "outputs": [],
   "source": [
    "query = \"What did the president say about Justice Breyer\"\n",
    "docs = docsearch.similarity_search(query)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "005a47e9",
   "metadata": {},
   "outputs": [],
   "source": [
    "from langchain.chains.qa_with_sources import load_qa_with_sources_chain\n",
    "from langchain.llms import OpenAI"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "d82f899a",
   "metadata": {},
   "source": [
    "### The `stuff` Chain\n",
    "\n",
    "This sections shows results of using the `stuff` Chain to do question answering with sources."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "fc1a5ed6",
   "metadata": {},
   "outputs": [],
   "source": [
    "chain = load_qa_with_sources_chain(OpenAI(temperature=0), chain_type=\"stuff\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "e239964b",
   "metadata": {},
   "outputs": [],
   "source": [
    "docs = [Document(page_content=t, metadata={\"source\": i}) for i, t in enumerate(texts[:3])]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "7d766417",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'output_text': ' The president did not mention Justice Breyer.\\nSOURCES: 0-pl, 1-pl, 2-pl'}"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "query = \"What did the president say about Justice Breyer\"\n",
    "chain({\"input_documents\": docs, \"question\": query}, return_only_outputs=True)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "c5dbb304",
   "metadata": {},
   "source": [
    "### The `map_reduce` Chain\n",
    "\n",
    "This sections shows results of using the `map_reduce` Chain to do question answering with sources."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "921db0a4",
   "metadata": {},
   "outputs": [],
   "source": [
    "chain = load_qa_with_sources_chain(OpenAI(temperature=0), chain_type=\"map_reduce\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "id": "e417926a",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'output_text': ' The president did not mention Justice Breyer.\\nSOURCES: 0, 1, 2'}"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "query = \"What did the president say about Justice Breyer\"\n",
    "chain({\"input_documents\": docs, \"question\": query}, return_only_outputs=True)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "5bf0e1ab",
   "metadata": {},
   "source": [
    "### The `refine` Chain\n",
    "\n",
    "This sections shows results of using the `refine` Chain to do question answering with sources."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "id": "904835c8",
   "metadata": {},
   "outputs": [],
   "source": [
    "chain = load_qa_with_sources_chain(OpenAI(temperature=0), chain_type=\"refine\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "id": "f60875c6",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'output_text': \"\\n\\nThe president did not mention Justice Breyer in his speech to the European Parliament. He discussed the situation in Ukraine, the NATO Alliance, and the United States' response to Putin's attack on Ukraine. He spoke about the extensive preparation and coalition building that was done in advance of the attack, and the unified response from the European Union, Canada, Japan, Korea, Australia, New Zealand, and many other countries. He also discussed the economic sanctions that have been imposed on Russia, and the effects they have had on Putin's war fund. Source: 1, 2\"}"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "query = \"What did the president say about Justice Breyer\"\n",
    "chain({\"input_documents\": docs, \"question\": query}, return_only_outputs=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "929620d0",
   "metadata": {},
   "outputs": [],
   "source": []
  }
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