refine.py — langchain Source File

Source Code

"""Combine documents by doing a first pass and then refining on more documents."""

from __future__ import annotations

from typing import Any

from langchain_core._api import deprecated
from langchain_core.callbacks import Callbacks
from langchain_core.documents import Document
from langchain_core.prompts import BasePromptTemplate, format_document
from langchain_core.prompts.prompt import PromptTemplate
from pydantic import ConfigDict, Field, model_validator

from langchain_classic.chains.combine_documents.base import (
    BaseCombineDocumentsChain,
)
from langchain_classic.chains.llm import LLMChain


def _get_default_document_prompt() -> PromptTemplate:
    return PromptTemplate(input_variables=["page_content"], template="{page_content}")


@deprecated(
    since="0.3.1",
    removal="1.0",
    message=(
        "This class is deprecated. Please see the migration guide here for "
        "a recommended replacement: "
        "https://python.langchain.com/docs/versions/migrating_chains/refine_docs_chain/"
    ),
)
class RefineDocumentsChain(BaseCombineDocumentsChain):
    """Combine documents by doing a first pass and then refining on more documents.

    This algorithm first calls `initial_llm_chain` on the first document, passing
    that first document in with the variable name `document_variable_name`, and
    produces a new variable with the variable name `initial_response_name`.

    Then, it loops over every remaining document. This is called the "refine" step.
    It calls `refine_llm_chain`,
    passing in that document with the variable name `document_variable_name`
    as well as the previous response with the variable name `initial_response_name`.

    Example:
        ```python
        from langchain_classic.chains import RefineDocumentsChain, LLMChain
        from langchain_core.prompts import PromptTemplate
        from langchain_openai import OpenAI

        # This controls how each document will be formatted. Specifically,
        # it will be passed to `format_document` - see that function for more
        # details.
        document_prompt = PromptTemplate(
            input_variables=["page_content"], template="{page_content}"
        )
        document_variable_name = "context"
        model = OpenAI()
        # The prompt here should take as an input variable the
        # `document_variable_name`
// ... (170 more lines)