分类目录：《大模型从入门到应用》总目录
LangChain系列文章：
基础知识快速入门 安装与环境配置链（Chains）、代理（Agent:）和记忆（Memory）快速开发聊天模型 模型（Models） 基础知识大型语言模型（LLMs） 基础知识LLM的异步API、自定义LLM包装器、虚假LLM和人类输入LLM（Human Input LLM）缓存LLM的调用结果加载与保存LLM类、流式传输LLM与Chat Model响应和跟踪tokens使用情况 聊天模型（Chat Models） 基础知识使用少量示例和响应流式传输 文本嵌入模型 Aleph Alpha、Amazon Bedrock、Azure OpenAI、Cohere等Embaas、Fake Embeddings、Google Vertex AI PaLM等 提示（Prompts） 基础知识提示模板 基础知识连接到特征存储创建自定义提示模板和含有Few-Shot示例的提示模板部分填充的提示模板和提示合成序列化提示信息 示例选择器（Example Selectors）输出解析器（Output Parsers） 记忆（Memory） 基础知识记忆的类型 会话缓存记忆、会话缓存窗口记忆和实体记忆对话知识图谱记忆、对话摘要记忆和会话摘要缓冲记忆对话令牌缓冲存储器和基于向量存储的记忆 将记忆添加到LangChain组件中自定义对话记忆与自定义记忆类聊天消息记录记忆的存储与应用 索引（Indexes） 基础知识文档加载器（Document Loaders）文本分割器（Text Splitters）向量存储器（Vectorstores）检索器（Retrievers） 链（Chains） 基础知识通用功能 自定义Chain和Chain的异步APILLMChain和RouterChainSequentialChain和TransformationChain链的保存（序列化）与加载（反序列化） 链与索引 文档分析和基于文档的聊天问答的基础知识图问答（Graph QA）和带来源的问答（Q&A with Sources）检索式问答文本摘要（Summarization）、HyDE和向量数据库的文本生成 代理（Agents） 基础知识代理类型自定义代理（Custom Agent）自定义MRKL代理带有ChatModel的LLM聊天自定义代理和自定义多操作代理（Custom MultiAction Agent）工具 基础知识自定义工具（Custom Tools）多输入工具和工具输入模式人工确认工具验证和Tools作为OpenAI函数 工具包（Toolkit）代理执行器（Agent Executor） 结合使用Agent和VectorStore使用Agents的异步API和创建ChatGPT克隆处理解析错误、访问中间步骤和限制最大迭代次数为代理程序设置超时时间和限制最大迭代次数和为代理程序和其工具添加共享内存 计划与执行 回调函数（Callbacks）
----### LLM的异步API
LangChain通过利用asyncio库为LLM提供异步支持。异步支持对于同时调用多个LLM特别有用，因为这些调用是网络绑定的。当前，支持的LLMs包括OpenAI、PromptLayerOpenAI、ChatOpenAI和Anthropic，后续还会提供其他LLMs的异步支持。我们可以使用agenerate方法异步调用OpenAI LLM：
import timeimport asynciofrom langchain.llms import OpenAIdef generate_serially():llm = OpenAI(temperature=0.9)for _ in range(10):resp = llm.generate(["Hello, how are you?"])print(resp.generations[0][0].text)async def async_generate(llm):resp = await llm.agenerate(["Hello, how are you?"])print(resp.generations[0][0].text)async def generate_concurrently():llm = OpenAI(temperature=0.9)tasks = [async_generate(llm) for _ in range(10)]await asyncio.gather(*tasks)s = time.perf_counter()# 如果在Jupyter之外运行，请使用asyncio.run(generate_concurrently())await generate_concurrently() elapsed = time.perf_counter() - sprint('\033[1m' + f"Concurrent executed in {elapsed:0.2f} seconds." + '\033[0m')s = time.perf_counter()generate_serially()elapsed = time.perf_counter() - sprint('\033[1m' + f"Serial executed in {elapsed:0.2f} seconds." + '\033[0m')
输出：
I'm doing well, thank you. How about you?I'm doing well, thank you. How about you?I'm doing well, how about you?I'm doing well, thank you. How about you?I'm doing well, thank you. How about you?I'm doing well, thank you. How about yourself?I'm doing well, thank you! How about you?I'm doing well, thank you. How about you?I'm doing well, thank you! How about you?I'm doing well, thank you. How about you?[1mConcurrent executed in 1.39 seconds.I'm doing well, thank you. How about you?I'm doing well, thank you. How about you?I'm doing well, thank you. How about you?I'm doing well, thank you. How about you?I'm doing well, thank you. How about yourself?I'm doing well, thanks for asking. How about you?I'm doing well, thanks! How about you?I'm doing well, thank you. How about you?I'm doing well, thank you. How about yourself?I'm doing well, thanks for asking. How about you?[1mSerial executed in 5.77 seconds.
编写自定义LLM包装器
本部分介绍如何创建自定义的LLM包装器，这部分的内容使我们可以使用自己的LLM或与LangChain支持的包装器不同的包装器。一个自定义LLM只需要实现一件必须的事情：
一个_call方法，它接受一个字符串、一些可选的停止词，并返回一个字符串。
它还可以实现一个可选的事情:
一个_identifying_params属性，用于帮助打印这个类。应该返回一个字典。
让我们实现一个非常简单的自定义LLM，它只返回输入的前 N N N个字符：
from typing import Any, List, Mapping, Optionalfrom langchain.callbacks.manager import CallbackManagerForLLMRunfrom langchain.llms.base import LLMclass CustomLLM(LLM):n: int@propertydef _llm_type(self) -> str:return "custom"def _call(self,prompt: str,stop: Optional[List[str]] = None,run_manager: Optional[CallbackManagerForLLMRun] = None,) -> str:if stop is not None:raise ValueError("stop kwargs are not permitted.")return prompt[:self.n]@propertydef _identifying_params(self) -> Mapping[str, Any]:"""Get the identifying parameters."""return {"n": self.n}
我们现在可以像使用其他LLM一样使用它了：
llm = CustomLLM(n=10)llm("This is a foobar thing")
输出：
'This is a '
我们还可以打印LLM并查看它的自定义打印：
print(llm)
输出：
CustomLLMParams: {'n': 10}
虚假LLM
LangChain提供了一个用于测试的虚假LLM类，这使我们可以模拟对LLM的调用，并模拟LLM以特定方式响应时会发生什么。我们从在代理中使用FakeLLM开始：
from langchain.llms.fake import FakeListLLMfrom langchain.agents import load_toolsfrom langchain.agents import initialize_agentfrom langchain.agents import AgentTypetools = load_tools(["python_repl"])responses=["Action: Python REPL\nAction Input: print(2 + 2)","Final Answer: 4"]llm = FakeListLLM(responses=responses)agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)agent.run("whats 2 + 2")
日志输出：
> Entering new AgentExecutor chain...Action: Python REPLAction Input: print(2 + 2)Observation: 4Thought:Final Answer: 4> Finished chain.
输出：
'4'
人类输入LLM（Human Input LLM）
与fake LLM类似，LangChain提供了一个伪LLM课程，可用于测试、调试或教育目的。这使我们可以模拟对LLM的调用，并模拟人类接收提示时的响应方式，我们从在代理中使用Human Input LLM开始：
from langchain.llms.human import HumanInputLLMfrom langchain.agents import load_toolsfrom langchain.agents import initialize_agentfrom langchain.agents import AgentType
由于我们后面将使用WikipediaQueryRun工具，如果我们还没有安装wikipedia包，我们需要安装它：
pip install wikipedia
接着我们就可以开始使用wikipedia：
tools = load_tools(["wikipedia"])llm = HumanInputLLM(prompt_func=lambda prompt: print(f"\n===PROMPT====\n{prompt}\n=====END OF PROMPT======"))agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)agent.run("What is 'Bocchi the Rock!'?")
日志输出：
> Entering new AgentExecutor chain...===PROMPT====Answer the following questions as best you can. You have access to the following tools:Wikipedia: A wrapper around Wikipedia. Useful for when you need to answer general questions about people, places, companies, historical events, or other subjects. Input should be a search query.Use the following format:Question: the input question you must answerThought: you should always think about what to doAction: the action to take, should be one of [Wikipedia]Action Input: the input to the actionObservation: the result of the action... (this Thought/Action/Action Input/Observation can repeat N times)Thought: I now know the final answerFinal Answer: the final answer to the original input questionBegin!Question: What is 'Bocchi the Rock!'?Thought:=====END OF PROMPT======I need to use a tool.Action: WikipediaAction Input: Bocchi the Rock!, Japanese four-panel manga and anime series.Observation: Page: Bocchi the Rock!Summary: Bocchi the Rock! (ぼっち・ざ・ろっく!, Bocchi Za Rokku!) is a Japanese four-panel manga series written and illustrated by Aki Hamaji. It has been serialized in Houbunsha's seinen manga magazine Manga Time Kirara Max since December . Its chapters have been collected in five tankōbon volumes as of November .An anime television series adaptation produced by CloverWorks aired from October to December . The series has been praised for its writing, comedy, characters, and depiction of social anxiety, with the anime's visual creativity receiving acclaim.Page: Manga Time KiraraSummary: Manga Time Kirara (まんがタイムきらら, Manga Taimu Kirara) is a Japanese seinen manga magazine published by Houbunsha which mainly serializes four-panel manga. The magazine is sold on the ninth of each month and was first published as a special edition of Manga Time, another Houbunsha magazine, on May 17, 2002. Characters from this magazine have appeared in a crossover role-playing game called Kirara Fantasia.Page: Manga Time Kirara MaxSummary: Manga Time Kirara Max (まんがタイムきららMAX) is a Japanese four-panel seinen manga magazine published by Houbunsha. It is the third magazine of the "Kirara" series, after "Manga Time Kirara" and "Manga Time Kirara Carat". The first issue was released on September 29, . Currently the magazine is released on the 19th of each month.Thought:===PROMPT====Answer the following questions as best you can. You have access to the following tools:Wikipedia: A wrapper around Wikipedia. Useful for when you need to answer general questions about people, places, companies, historical events, or other subjects. Input should be a search query.Use the following format:Question: the input question you must answerThought: you should always think about what to doAction: the action to take, should be one of [Wikipedia]Action Input: the input to the actionObservation: the result of the action... (this Thought/Action/Action Input/Observation can repeat N times)Thought: I now know the final answerFinal Answer: the final answer to the original input questionBegin!Question: What is 'Bocchi the Rock!'?Thought:I need to use a tool.Action: WikipediaAction Input: Bocchi the Rock!, Japanese four-panel manga and anime series.Observation: Page: Bocchi the Rock!Summary: Bocchi the Rock! (ぼっち・ざ・ろっく!, Bocchi Za Rokku!) is a Japanese four-panel manga series written and illustrated by Aki Hamaji. It has been serialized in Houbunsha's seinen manga magazine Manga Time Kirara Max since December . Its chapters have been collected in five tankōbon volumes as of November .An anime television series adaptation produced by CloverWorks aired from October to December . The series has been praised for its writing, comedy, characters, and depiction of social anxiety, with the anime's visual creativity receiving acclaim.Page: Manga Time KiraraSummary: Manga Time Kirara (まんがタイムきらら, Manga Taimu Kirara) is a Japanese seinen manga magazine published by Houbunsha which mainly serializes four-panel manga. The magazine is sold on the ninth of each month and was first published as a special edition of Manga Time, another Houbunsha magazine, on May 17, 2002. Characters from this magazine have appeared in a crossover role-playing game called Kirara Fantasia.Page: Manga Time Kirara MaxSummary: Manga Time Kirara Max (まんがタイムきららMAX) is a Japanese four-panel seinen manga magazine published by Houbunsha. It is the third magazine of the "Kirara" series, after "Manga Time Kirara" and "Manga Time Kirara Carat". The first issue was released on September 29, . Currently the magazine is released on the 19th of each month.Thought:=====END OF PROMPT======These are not relevant articles.Action: WikipediaAction Input: Bocchi the Rock!, Japanese four-panel manga series written and illustrated by Aki Hamaji.Observation: Page: Bocchi the Rock!Summary: Bocchi the Rock! (ぼっち・ざ・ろっく!, Bocchi Za Rokku!) is a Japanese four-panel manga series written and illustrated by Aki Hamaji. It has been serialized in Houbunsha's seinen manga magazine Manga Time Kirara Max since December . Its chapters have been collected in five tankōbon volumes as of November .An anime television series adaptation produced by CloverWorks aired from October to December . The series has been praised for its writing, comedy, characters, and depiction of social anxiety, with the anime's visual creativity receiving acclaim.Thought:===PROMPT====Answer the following questions as best you can. You have access to the following tools:Wikipedia: A wrapper around Wikipedia. Useful for when you need to answer general questions about people, places, companies, historical events, or other subjects. Input should be a search query.Use the following format:Question: the input question you must answerThought: you should always think about what to doAction: the action to take, should be one of [Wikipedia]Action Input: the input to the actionObservation: the result of the action... (this Thought/Action/Action Input/Observation can repeat N times)Thought: I now know the final answerFinal Answer: the final answer to the original input questionBegin!Question: What is 'Bocchi the Rock!'?Thought:I need to use a tool.Action: WikipediaAction Input: Bocchi the Rock!, Japanese four-panel manga and anime series.Observation: Page: Bocchi the Rock!Summary: Bocchi the Rock! (ぼっち・ざ・ろっく!, Bocchi Za Rokku!) is a Japanese four-panel manga series written and illustrated by Aki Hamaji. It has been serialized in Houbunsha's seinen manga magazine Manga Time Kirara Max since December . Its chapters have been collected in five tankōbon volumes as of November .An anime television series adaptation produced by CloverWorks aired from October to December . The series has been praised for its writing, comedy, characters, and depiction of social anxiety, with the anime's visual creativity receiving acclaim.Page: Manga Time KiraraSummary: Manga Time Kirara (まんがタイムきらら, Manga Taimu Kirara) is a Japanese seinen manga magazine published by Houbunsha which mainly serializes four-panel manga. The magazine is sold on the ninth of each month and was first published as a special edition of Manga Time, another Houbunsha magazine, on May 17, 2002. Characters from this magazine have appeared in a crossover role-playing game called Kirara Fantasia.Page: Manga Time Kirara MaxSummary: Manga Time Kirara Max (まんがタイムきららMAX) is a Japanese four-panel seinen manga magazine published by Houbunsha. It is the third magazine of the "Kirara" series, after "Manga Time Kirara" and "Manga Time Kirara Carat". The first issue was released on September 29, . Currently the magazine is released on the 19th of each month.Thought:These are not relevant articles.Action: WikipediaAction Input: Bocchi the Rock!, Japanese four-panel manga series written and illustrated by Aki Hamaji.Observation: Page: Bocchi the Rock!Summary: Bocchi the Rock! (ぼっち・ざ・ろっく!, Bocchi Za Rokku!) is a Japanese four-panel manga series written and illustrated by Aki Hamaji. It has been serialized in Houbunsha's seinen manga magazine Manga Time Kirara Max since December . Its chapters have been collected in five tankōbon volumes as of November .An anime television series adaptation produced by CloverWorks aired from October to December . The series has been praised for its writing, comedy, characters, and depiction of social anxiety, with the anime's visual creativity receiving acclaim.Thought:=====END OF PROMPT======It worked.Final Answer: Bocchi the Rock! is a four-panel manga series and anime television series. The series has been praised for its writing, comedy, characters, and depiction of social anxiety, with the anime's visual creativity receiving acclaim.> Finished chain.
输出：
"Bocchi the Rock! is a four-panel manga series and anime television series. The series has been praised for its writing, comedy, characters, and depiction of social anxiety, with the anime's visual creativity receiving acclaim."
参考文献：
[1] LangChain 🦜️🔗 中文网，跟着LangChain一起学LLM/GPT开发：/
[2] LangChain中文网 - LangChain 是一个用于开发由语言模型驱动的应用程序的框架：/
大模型从入门到应用——LangChain：模型（Models）-[大型语言模型（LLMs）：LLM的异步API 自定义LLM包装器 虚假LLM和人类输入LLM（Human Input LLM）]
