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Sub question

SubQuestionQueryEngine #

Bases: BaseQueryEngine

子问题查询引擎。

一个查询引擎,将复杂查询(例如比较和对比)分解为多个子问题及其目标查询引擎以进行执行。 在执行所有子问题后,收集所有响应并发送到响应合成器以生成最终响应。

Parameters:

Name Type Description Default
question_gen BaseQuestionGenerator

用于根据复杂问题和工具生成子问题的模块。

required
response_synthesizer BaseSynthesizer

用于生成最终响应的响应合成器。

required
query_engine_tools Sequence[QueryEngineTool]

用于回答子问题的工具。

required
verbose bool

是否打印中间问题和答案。默认为True。

True
use_async bool

是否使用asyncio执行子问题。默认为True。

False
Source code in llama_index/core/query_engine/sub_question_query_engine.py
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class SubQuestionQueryEngine(BaseQueryEngine):
    """子问题查询引擎。

    一个查询引擎,将复杂查询(例如比较和对比)分解为多个子问题及其目标查询引擎以进行执行。
    在执行所有子问题后,收集所有响应并发送到响应合成器以生成最终响应。

    Args:
        question_gen (BaseQuestionGenerator): 用于根据复杂问题和工具生成子问题的模块。
        response_synthesizer (BaseSynthesizer): 用于生成最终响应的响应合成器。
        query_engine_tools (Sequence[QueryEngineTool]): 用于回答子问题的工具。
        verbose (bool): 是否打印中间问题和答案。默认为True。
        use_async (bool): 是否使用asyncio执行子问题。默认为True。"""

    def __init__(
        self,
        question_gen: BaseQuestionGenerator,
        response_synthesizer: BaseSynthesizer,
        query_engine_tools: Sequence[QueryEngineTool],
        callback_manager: Optional[CallbackManager] = None,
        verbose: bool = True,
        use_async: bool = False,
    ) -> None:
        self._question_gen = question_gen
        self._response_synthesizer = response_synthesizer
        self._metadatas = [x.metadata for x in query_engine_tools]
        self._query_engines = {
            tool.metadata.name: tool.query_engine for tool in query_engine_tools
        }
        self._verbose = verbose
        self._use_async = use_async
        super().__init__(callback_manager)

    def _get_prompt_modules(self) -> PromptMixinType:
        """获取提示子模块。"""
        return {
            "question_gen": self._question_gen,
            "response_synthesizer": self._response_synthesizer,
        }

    @classmethod
    def from_defaults(
        cls,
        query_engine_tools: Sequence[QueryEngineTool],
        llm: Optional[LLM] = None,
        question_gen: Optional[BaseQuestionGenerator] = None,
        response_synthesizer: Optional[BaseSynthesizer] = None,
        service_context: Optional[ServiceContext] = None,
        verbose: bool = True,
        use_async: bool = True,
    ) -> "SubQuestionQueryEngine":
        callback_manager = callback_manager_from_settings_or_context(
            Settings, service_context
        )
        if len(query_engine_tools) > 0:
            callback_manager = query_engine_tools[0].query_engine.callback_manager

        llm = llm or llm_from_settings_or_context(Settings, service_context)
        if question_gen is None:
            try:
                from llama_index.question_gen.openai import (
                    OpenAIQuestionGenerator,
                )  # pants: no-infer-dep

                # try to use OpenAI function calling based question generator.
                # if incompatible, use general LLM question generator
                question_gen = OpenAIQuestionGenerator.from_defaults(llm=llm)

            except ImportError as e:
                raise ImportError(
                    "`llama-index-question-gen-openai` package cannot be found. "
                    "Please install it by using `pip install `llama-index-question-gen-openai`"
                )
            except ValueError:
                question_gen = LLMQuestionGenerator.from_defaults(llm=llm)

        synth = response_synthesizer or get_response_synthesizer(
            llm=llm,
            callback_manager=callback_manager,
            service_context=service_context,
            use_async=use_async,
        )

        return cls(
            question_gen,
            synth,
            query_engine_tools,
            callback_manager=callback_manager,
            verbose=verbose,
            use_async=use_async,
        )

    def _query(self, query_bundle: QueryBundle) -> RESPONSE_TYPE:
        with self.callback_manager.event(
            CBEventType.QUERY, payload={EventPayload.QUERY_STR: query_bundle.query_str}
        ) as query_event:
            sub_questions = self._question_gen.generate(self._metadatas, query_bundle)

            colors = get_color_mapping([str(i) for i in range(len(sub_questions))])

            if self._verbose:
                print_text(f"Generated {len(sub_questions)} sub questions.\n")

            if self._use_async:
                tasks = [
                    self._aquery_subq(sub_q, color=colors[str(ind)])
                    for ind, sub_q in enumerate(sub_questions)
                ]

                qa_pairs_all = run_async_tasks(tasks)
                qa_pairs_all = cast(List[Optional[SubQuestionAnswerPair]], qa_pairs_all)
            else:
                qa_pairs_all = [
                    self._query_subq(sub_q, color=colors[str(ind)])
                    for ind, sub_q in enumerate(sub_questions)
                ]

            # filter out sub questions that failed
            qa_pairs: List[SubQuestionAnswerPair] = list(filter(None, qa_pairs_all))

            nodes = [self._construct_node(pair) for pair in qa_pairs]

            source_nodes = [node for qa_pair in qa_pairs for node in qa_pair.sources]
            response = self._response_synthesizer.synthesize(
                query=query_bundle,
                nodes=nodes,
                additional_source_nodes=source_nodes,
            )

            query_event.on_end(payload={EventPayload.RESPONSE: response})

        return response

    async def _aquery(self, query_bundle: QueryBundle) -> RESPONSE_TYPE:
        with self.callback_manager.event(
            CBEventType.QUERY, payload={EventPayload.QUERY_STR: query_bundle.query_str}
        ) as query_event:
            sub_questions = await self._question_gen.agenerate(
                self._metadatas, query_bundle
            )

            colors = get_color_mapping([str(i) for i in range(len(sub_questions))])

            if self._verbose:
                print_text(f"Generated {len(sub_questions)} sub questions.\n")

            tasks = [
                self._aquery_subq(sub_q, color=colors[str(ind)])
                for ind, sub_q in enumerate(sub_questions)
            ]

            qa_pairs_all = await asyncio.gather(*tasks)
            qa_pairs_all = cast(List[Optional[SubQuestionAnswerPair]], qa_pairs_all)

            # filter out sub questions that failed
            qa_pairs: List[SubQuestionAnswerPair] = list(filter(None, qa_pairs_all))

            nodes = [self._construct_node(pair) for pair in qa_pairs]

            source_nodes = [node for qa_pair in qa_pairs for node in qa_pair.sources]
            response = await self._response_synthesizer.asynthesize(
                query=query_bundle,
                nodes=nodes,
                additional_source_nodes=source_nodes,
            )

            query_event.on_end(payload={EventPayload.RESPONSE: response})

        return response

    def _construct_node(self, qa_pair: SubQuestionAnswerPair) -> NodeWithScore:
        node_text = (
            f"Sub question: {qa_pair.sub_q.sub_question}\nResponse: {qa_pair.answer}"
        )
        return NodeWithScore(node=TextNode(text=node_text))

    async def _aquery_subq(
        self, sub_q: SubQuestion, color: Optional[str] = None
    ) -> Optional[SubQuestionAnswerPair]:
        try:
            with self.callback_manager.event(
                CBEventType.SUB_QUESTION,
                payload={EventPayload.SUB_QUESTION: SubQuestionAnswerPair(sub_q=sub_q)},
            ) as event:
                question = sub_q.sub_question
                query_engine = self._query_engines[sub_q.tool_name]

                if self._verbose:
                    print_text(f"[{sub_q.tool_name}] Q: {question}\n", color=color)

                response = await query_engine.aquery(question)
                response_text = str(response)

                if self._verbose:
                    print_text(f"[{sub_q.tool_name}] A: {response_text}\n", color=color)

                qa_pair = SubQuestionAnswerPair(
                    sub_q=sub_q, answer=response_text, sources=response.source_nodes
                )

                event.on_end(payload={EventPayload.SUB_QUESTION: qa_pair})

            return qa_pair
        except ValueError:
            logger.warning(f"[{sub_q.tool_name}] Failed to run {question}")
            return None

    def _query_subq(
        self, sub_q: SubQuestion, color: Optional[str] = None
    ) -> Optional[SubQuestionAnswerPair]:
        try:
            with self.callback_manager.event(
                CBEventType.SUB_QUESTION,
                payload={EventPayload.SUB_QUESTION: SubQuestionAnswerPair(sub_q=sub_q)},
            ) as event:
                question = sub_q.sub_question
                query_engine = self._query_engines[sub_q.tool_name]

                if self._verbose:
                    print_text(f"[{sub_q.tool_name}] Q: {question}\n", color=color)

                response = query_engine.query(question)
                response_text = str(response)

                if self._verbose:
                    print_text(f"[{sub_q.tool_name}] A: {response_text}\n", color=color)

                qa_pair = SubQuestionAnswerPair(
                    sub_q=sub_q, answer=response_text, sources=response.source_nodes
                )

                event.on_end(payload={EventPayload.SUB_QUESTION: qa_pair})

            return qa_pair
        except ValueError:
            logger.warning(f"[{sub_q.tool_name}] Failed to run {question}")
            return None

SubQuestionAnswerPair #

Bases: BaseModel

子问题和可选的答案对(如果已经回答)。

Source code in llama_index/core/query_engine/sub_question_query_engine.py
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class SubQuestionAnswerPair(BaseModel):
    """子问题和可选的答案对(如果已经回答)。"""

    sub_q: SubQuestion
    answer: Optional[str] = None
    sources: List[NodeWithScore] = Field(default_factory=list)