from_llm() — langchain Function Reference

Architecture documentation for the from_llm() function in eval_chain.py from the langchain codebase.

Function python LangChainCore Runnables calls 2 called by 1

Entity Profile

LangChainCore→ Runnables→ from_llm() — langchain Function Reference

Dependency Diagram

graph TD
  909f249d_6333_28c0_ed05_2bfa8676c170["from_llm()"]
  6b783916_2e41_8d2a_dba2_81813096b7c4["ContextQAEvalChain"]
  909f249d_6333_28c0_ed05_2bfa8676c170 -->|defined in| 6b783916_2e41_8d2a_dba2_81813096b7c4
  a3155b02_dbf2_ea43_042a_2d3c1404bdeb["from_llm()"]
  a3155b02_dbf2_ea43_042a_2d3c1404bdeb -->|calls| 909f249d_6333_28c0_ed05_2bfa8676c170
  5e40a8d3_ac36_a29a_8969_75ee97f0c328["_validate_input_vars()"]
  909f249d_6333_28c0_ed05_2bfa8676c170 -->|calls| 5e40a8d3_ac36_a29a_8969_75ee97f0c328
  a3155b02_dbf2_ea43_042a_2d3c1404bdeb["from_llm()"]
  909f249d_6333_28c0_ed05_2bfa8676c170 -->|calls| a3155b02_dbf2_ea43_042a_2d3c1404bdeb
  style 909f249d_6333_28c0_ed05_2bfa8676c170 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain/langchain_classic/evaluation/qa/eval_chain.py lines 257–279

    def from_llm(
        cls,
        llm: BaseLanguageModel,
        prompt: PromptTemplate | None = None,
        **kwargs: Any,
    ) -> ContextQAEvalChain:
        """Load QA Eval Chain from LLM.

        Args:
            llm: The base language model to use.
            prompt: A prompt template containing the `input_variables`:
                `'query'`, `'context'` and `'result'` that will be used as the prompt
                for evaluation.

                Defaults to `PROMPT`.
            **kwargs: Additional keyword arguments.

        Returns:
            The loaded QA eval chain.
        """
        prompt = prompt or CONTEXT_PROMPT
        cls._validate_input_vars(prompt)
        return cls(llm=llm, prompt=prompt, **kwargs)