Source code for langchain.evaluation.qa.generate_chain

"""LLM Chain for generating examples for question answering."""
from __future__ import annotations

from typing import Any

from langchain_core.language_models import BaseLanguageModel
from langchain_core.output_parsers import BaseLLMOutputParser
from langchain_core.pydantic_v1 import Field

from langchain.chains.llm import LLMChain
from langchain.evaluation.qa.generate_prompt import PROMPT
from langchain.output_parsers.regex import RegexParser

_QA_OUTPUT_PARSER = RegexParser(
    regex=r"QUESTION: (.*?)\n+ANSWER: (.*)", output_keys=["query", "answer"]
)


[docs]class QAGenerateChain(LLMChain): """LLM Chain for generating examples for question answering.""" output_parser: BaseLLMOutputParser = Field(default=_QA_OUTPUT_PARSER) output_key: str = "qa_pairs"
[docs] @classmethod def is_lc_serializable(cls) -> bool: return False
[docs] @classmethod def from_llm(cls, llm: BaseLanguageModel, **kwargs: Any) -> QAGenerateChain: """Load QA Generate Chain from LLM.""" return cls(llm=llm, prompt=PROMPT, **kwargs)