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Wednesday, November 15, 2023

A Full Information & Tutorial


At its core, LangChain is an modern framework tailor-made for crafting functions that leverage the capabilities of language fashions. It is a toolkit designed for builders to create functions which can be context-aware and able to refined reasoning.

This implies LangChain functions can perceive the context, equivalent to immediate directions or content material grounding responses and use language fashions for complicated reasoning duties, like deciding how one can reply or what actions to take. LangChain represents a unified method to growing clever functions, simplifying the journey from idea to execution with its various elements.

Understanding LangChain

LangChain is far more than only a framework; it is a full-fledged ecosystem comprising a number of integral elements.

  • Firstly, there are the LangChain Libraries, accessible in each Python and JavaScript. These libraries are the spine of LangChain, providing interfaces and integrations for numerous elements. They supply a fundamental runtime for combining these elements into cohesive chains and brokers, together with ready-made implementations for fast use.
  • Subsequent, we’ve LangChain Templates. These are a set of deployable reference architectures tailor-made for a wide selection of duties. Whether or not you are constructing a chatbot or a fancy analytical device, these templates provide a strong place to begin.
  • LangServe steps in as a flexible library for deploying LangChain chains as REST APIs. This device is important for turning your LangChain initiatives into accessible and scalable net providers.
  • Lastly, LangSmith serves as a developer platform. It is designed to debug, check, consider, and monitor chains constructed on any LLM framework. The seamless integration with LangChain makes it an indispensable device for builders aiming to refine and excellent their functions.

Collectively, these elements empower you to develop, productionize, and deploy functions with ease. With LangChain, you begin by writing your functions utilizing the libraries, referencing templates for steering. LangSmith then helps you in inspecting, testing, and monitoring your chains, guaranteeing that your functions are continuously bettering and prepared for deployment. Lastly, with LangServe, you may simply rework any chain into an API, making deployment a breeze.

Within the subsequent sections, we are going to delve deeper into how one can arrange LangChain and start your journey in creating clever, language model-powered functions.


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Set up and Setup

Are you able to dive into the world of LangChain? Setting it up is easy, and this information will stroll you thru the method step-by-step.

Step one in your LangChain journey is to put in it. You are able to do this simply utilizing pip or conda. Run the next command in your terminal:

pip set up langchain

For individuals who favor the newest options and are comfy with a bit extra journey, you may set up LangChain straight from the supply. Clone the repository and navigate to the langchain/libs/langchain listing. Then, run:

pip set up -e .

For experimental options, contemplate putting in langchain-experimental. It is a package deal that accommodates cutting-edge code and is meant for analysis and experimental functions. Set up it utilizing:

pip set up langchain-experimental

LangChain CLI is a helpful device for working with LangChain templates and LangServe initiatives. To put in the LangChain CLI, use:

pip set up langchain-cli

LangServe is important for deploying your LangChain chains as a REST API. It will get put in alongside the LangChain CLI.


LangChain typically requires integrations with mannequin suppliers, information shops, APIs, and so forth. For this instance, we’ll use OpenAI’s mannequin APIs. Set up the OpenAI Python package deal utilizing:

pip set up openai

To entry the API, set your OpenAI API key as an setting variable:

export OPENAI_API_KEY="your_api_key"

Alternatively, move the important thing straight in your python setting:

import os
os.environ['OPENAI_API_KEY'] = 'your_api_key'

LangChain permits for the creation of language mannequin functions by way of modules. These modules can both stand alone or be composed for complicated use instances. These modules are –

  • Mannequin I/O: Facilitates interplay with numerous language fashions, dealing with their inputs and outputs effectively.
  • Retrieval: Allows entry to and interplay with application-specific information, essential for dynamic information utilization.
  • Brokers: Empower functions to pick out acceptable instruments based mostly on high-level directives, enhancing decision-making capabilities.
  • Chains: Presents pre-defined, reusable compositions that function constructing blocks for utility improvement.
  • Reminiscence: Maintains utility state throughout a number of chain executions, important for context-aware interactions.

Every module targets particular improvement wants, making LangChain a complete toolkit for creating superior language mannequin functions.

Together with the above elements, we even have LangChain Expression Language (LCEL), which is a declarative solution to simply compose modules collectively, and this permits the chaining of elements utilizing a common Runnable interface.

LCEL seems one thing like this –

from langchain.chat_models import ChatOpenAI
from langchain.prompts import ChatPromptTemplate
from langchain.schema import BaseOutputParser

# Instance chain
chain = ChatPromptTemplate() | ChatOpenAI() | CustomOutputParser()

Now that we’ve lined the fundamentals, we are going to proceed on to:

  • Dig deeper into every Langchain module intimately.
  • Learn to use LangChain Expression Language.
  • Discover widespread use instances and implement them.
  • Deploy an end-to-end utility with LangServe.
  • Take a look at LangSmith for debugging, testing, and monitoring.

Let’s get began!

Module I : Mannequin I/O

In LangChain, the core factor of any utility revolves across the language mannequin. This module gives the important constructing blocks to interface successfully with any language mannequin, guaranteeing seamless integration and communication.

Key Parts of Mannequin I/O
  1. LLMs and Chat Fashions (used interchangeably):
    • LLMs:
      • Definition: Pure textual content completion fashions.
      • Enter/Output: Take a textual content string as enter and return a textual content string as output.
    • Chat Fashions
    • Definition: Fashions that use a language mannequin as a base however differ in enter and output codecs.
    • Enter/Output: Settle for an inventory of chat messages as enter and return a Chat Message.
  • Prompts: Templatize, dynamically choose, and handle mannequin inputs. Permits for the creation of versatile and context-specific prompts that information the language mannequin’s responses.
  • Output Parsers: Extract and format info from mannequin outputs. Helpful for changing the uncooked output of language fashions into structured information or particular codecs wanted by the applying.
  • LLMs

    LangChain’s integration with Giant Language Fashions (LLMs) like OpenAI, Cohere, and Hugging Face is a basic facet of its performance. LangChain itself doesn’t host LLMs however presents a uniform interface to work together with numerous LLMs.

    This part gives an outline of utilizing the OpenAI LLM wrapper in LangChain, relevant to different LLM varieties as effectively. We have now already put in this within the “Getting Began” part. Allow us to initialize the LLM.

    from langchain.llms import OpenAI
    llm = OpenAI()
    
    • LLMs implement the Runnable interface, the fundamental constructing block of the LangChain Expression Language (LCEL). This implies they assist invokeainvokestreamastreambatchabatchastream_log calls.
    • LLMs settle for strings as inputs, or objects which may be coerced to string prompts, together with Record[BaseMessage] and PromptValue. (extra on these later)

    Allow us to take a look at some examples.

    response = llm.invoke("Record the seven wonders of the world.")
    print(response)
    

    You’ll be able to alternatively name the stream technique to stream the textual content response.

    for chunk in llm.stream("The place have been the 2012 Olympics held?"):
        print(chunk, finish="", flush=True)
    
    Chat Fashions

    LangChain’s integration with chat fashions, a specialised variation of language fashions, is important for creating interactive chat functions. Whereas they make the most of language fashions internally, chat fashions current a definite interface centered round chat messages as inputs and outputs. This part gives an in depth overview of utilizing OpenAI’s chat mannequin in LangChain.

    from langchain.chat_models import ChatOpenAI
    chat = ChatOpenAI()
    

    Chat fashions in LangChain work with totally different message varieties equivalent to AIMessage, HumanMessage, SystemMessage, FunctionMessage, and ChatMessage (with an arbitrary function parameter). Usually, HumanMessage, AIMessage, and SystemMessage are probably the most steadily used.

    Chat fashions primarily settle for Record[BaseMessage] as inputs. Strings may be transformed to HumanMessage, and PromptValue can be supported.

    from langchain.schema.messages import HumanMessage, SystemMessage
    messages = [
        SystemMessage(content="You are Micheal Jordan."),
        HumanMessage(content="Which shoe manufacturer are you associated with?"),
    ]
    response = chat.invoke(messages)
    print(response.content material)

    Prompts

    Prompts are important in guiding language fashions to generate related and coherent outputs. They’ll vary from easy directions to complicated few-shot examples. In LangChain, dealing with prompts is usually a very streamlined course of, because of a number of devoted courses and features.

    LangChain’s PromptTemplate class is a flexible device for creating string prompts. It makes use of Python’s str.format syntax, permitting for dynamic immediate technology. You’ll be able to outline a template with placeholders and fill them with particular values as wanted.

    from langchain.prompts import PromptTemplate
    
    # Easy immediate with placeholders
    prompt_template = PromptTemplate.from_template(
        "Inform me a {adjective} joke about {content material}."
    )
    
    # Filling placeholders to create a immediate
    filled_prompt = prompt_template.format(adjective="humorous", content material="robots")
    print(filled_prompt)

    For chat fashions, prompts are extra structured, involving messages with particular roles. LangChain presents ChatPromptTemplate for this function.

    from langchain.prompts import ChatPromptTemplate
    
    # Defining a chat immediate with numerous roles
    chat_template = ChatPromptTemplate.from_messages(
        [
            ("system", "You are a helpful AI bot. Your name is {name}."),
            ("human", "Hello, how are you doing?"),
            ("ai", "I'm doing well, thanks!"),
            ("human", "{user_input}"),
        ]
    )
    
    # Formatting the chat immediate
    formatted_messages = chat_template.format_messages(identify="Bob", user_input="What's your identify?")
    for message in formatted_messages:
        print(message)
    

    This method permits for the creation of interactive, participating chatbots with dynamic responses.

    Each PromptTemplate and ChatPromptTemplate combine seamlessly with the LangChain Expression Language (LCEL), enabling them to be a part of bigger, complicated workflows. We’ll focus on extra on this later.

    Customized immediate templates are typically important for duties requiring distinctive formatting or particular directions. Making a customized immediate template entails defining enter variables and a customized formatting technique. This flexibility permits LangChain to cater to a wide selection of application-specific necessities. Learn extra right here.

    LangChain additionally helps few-shot prompting, enabling the mannequin to study from examples. This function is important for duties requiring contextual understanding or particular patterns. Few-shot immediate templates may be constructed from a set of examples or by using an Instance Selector object. Learn extra right here.

    Output Parsers

    Output parsers play an important function in Langchain, enabling customers to construction the responses generated by language fashions. On this part, we are going to discover the idea of output parsers and supply code examples utilizing Langchain’s PydanticOutputParser, SimpleJsonOutputParser, CommaSeparatedListOutputParser, DatetimeOutputParser, and XMLOutputParser.

    PydanticOutputParser

    Langchain gives the PydanticOutputParser for parsing responses into Pydantic information constructions. Under is a step-by-step instance of how one can use it:

    from typing import Record
    from langchain.llms import OpenAI
    from langchain.output_parsers import PydanticOutputParser
    from langchain.prompts import PromptTemplate
    from langchain.pydantic_v1 import BaseModel, Subject, validator
    
    # Initialize the language mannequin
    mannequin = OpenAI(model_name="text-davinci-003", temperature=0.0)
    
    # Outline your required information construction utilizing Pydantic
    class Joke(BaseModel):
        setup: str = Subject(description="query to arrange a joke")
        punchline: str = Subject(description="reply to resolve the joke")
    
        @validator("setup")
        def question_ends_with_question_mark(cls, subject):
            if subject[-1] != "?":
                increase ValueError("Badly fashioned query!")
            return subject
    
    # Arrange a PydanticOutputParser
    parser = PydanticOutputParser(pydantic_object=Joke)
    
    # Create a immediate with format directions
    immediate = PromptTemplate(
        template="Reply the person question.n{format_instructions}n{question}n",
        input_variables=["query"],
        partial_variables={"format_instructions": parser.get_format_instructions()},
    )
    
    # Outline a question to immediate the language mannequin
    question = "Inform me a joke."
    
    # Mix immediate, mannequin, and parser to get structured output
    prompt_and_model = immediate | mannequin
    output = prompt_and_model.invoke({"question": question})
    
    # Parse the output utilizing the parser
    parsed_result = parser.invoke(output)
    
    # The result's a structured object
    print(parsed_result)
    

    The output shall be:

    SimpleJsonOutputParser

    Langchain’s SimpleJsonOutputParser is used whenever you need to parse JSON-like outputs. This is an instance:

    from langchain.output_parsers.json import SimpleJsonOutputParser
    
    # Create a JSON immediate
    json_prompt = PromptTemplate.from_template(
        "Return a JSON object with `birthdate` and `birthplace` key that solutions the next query: {query}"
    )
    
    # Initialize the JSON parser
    json_parser = SimpleJsonOutputParser()
    
    # Create a series with the immediate, mannequin, and parser
    json_chain = json_prompt | mannequin | json_parser
    
    # Stream by way of the outcomes
    result_list = listing(json_chain.stream({"query": "When and the place was Elon Musk born?"}))
    
    # The result's an inventory of JSON-like dictionaries
    print(result_list)

    CommaSeparatedListOutputParser

    The CommaSeparatedListOutputParser is helpful whenever you need to extract comma-separated lists from mannequin responses. This is an instance:

    from langchain.output_parsers import CommaSeparatedListOutputParser
    from langchain.prompts import PromptTemplate
    from langchain.llms import OpenAI
    
    # Initialize the parser
    output_parser = CommaSeparatedListOutputParser()
    
    # Create format directions
    format_instructions = output_parser.get_format_instructions()
    
    # Create a immediate to request an inventory
    immediate = PromptTemplate(
        template="Record 5 {topic}.n{format_instructions}",
        input_variables=["subject"],
        partial_variables={"format_instructions": format_instructions}
    )
    
    # Outline a question to immediate the mannequin
    question = "English Premier League Groups"
    
    # Generate the output
    output = mannequin(immediate.format(topic=question))
    
    # Parse the output utilizing the parser
    parsed_result = output_parser.parse(output)
    
    # The result's an inventory of things
    print(parsed_result)

    DatetimeOutputParser

    Langchain’s DatetimeOutputParser is designed to parse datetime info. This is how one can use it:

    from langchain.prompts import PromptTemplate
    from langchain.output_parsers import DatetimeOutputParser
    from langchain.chains import LLMChain
    from langchain.llms import OpenAI
    
    # Initialize the DatetimeOutputParser
    output_parser = DatetimeOutputParser()
    
    # Create a immediate with format directions
    template = """
    Reply the person's query:
    {query}
    {format_instructions}
    """
    
    immediate = PromptTemplate.from_template(
        template,
        partial_variables={"format_instructions": output_parser.get_format_instructions()},
    )
    
    # Create a series with the immediate and language mannequin
    chain = LLMChain(immediate=immediate, llm=OpenAI())
    
    # Outline a question to immediate the mannequin
    question = "when did Neil Armstrong land on the moon when it comes to GMT?"
    
    # Run the chain
    output = chain.run(question)
    
    # Parse the output utilizing the datetime parser
    parsed_result = output_parser.parse(output)
    
    # The result's a datetime object
    print(parsed_result)

    These examples showcase how Langchain’s output parsers can be utilized to construction numerous kinds of mannequin responses, making them appropriate for various functions and codecs. Output parsers are a priceless device for enhancing the usability and interpretability of language mannequin outputs in Langchain.


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    Module II : Retrieval

    Retrieval in LangChain performs an important function in functions that require user-specific information, not included within the mannequin’s coaching set. This course of, often known as Retrieval Augmented Era (RAG), entails fetching exterior information and integrating it into the language mannequin’s technology course of. LangChain gives a complete suite of instruments and functionalities to facilitate this course of, catering to each easy and complicated functions.

    LangChain achieves retrieval by way of a sequence of elements which we are going to focus on one after the other.

    Doc Loaders

    Doc loaders in LangChain allow the extraction of information from numerous sources. With over 100 loaders accessible, they assist a variety of doc varieties, apps and sources (personal s3 buckets, public web sites, databases).

    You’ll be able to select a doc loader based mostly in your necessities right here.

    All these loaders ingest information into Doc courses. We’ll discover ways to use information ingested into Doc courses later.

    Textual content File Loader: Load a easy .txt file right into a doc.

    from langchain.document_loaders import TextLoader
    
    loader = TextLoader("./pattern.txt")
    doc = loader.load()
    

    CSV Loader: Load a CSV file right into a doc.

    from langchain.document_loaders.csv_loader import CSVLoader
    
    loader = CSVLoader(file_path="./example_data/pattern.csv")
    paperwork = loader.load()
    

    We will select to customise the parsing by specifying subject names –

    loader = CSVLoader(file_path="./example_data/mlb_teams_2012.csv", csv_args={
        'delimiter': ',',
        'quotechar': '"',
        'fieldnames': ['MLB Team', 'Payroll in millions', 'Wins']
    })
    paperwork = loader.load()
    

    PDF Loaders: PDF Loaders in LangChain provide numerous strategies for parsing and extracting content material from PDF recordsdata. Every loader caters to totally different necessities and makes use of totally different underlying libraries. Under are detailed examples for every loader.

    PyPDFLoader is used for fundamental PDF parsing.

    from langchain.document_loaders import PyPDFLoader
    
    loader = PyPDFLoader("example_data/layout-parser-paper.pdf")
    pages = loader.load_and_split()
    

    MathPixLoader is right for extracting mathematical content material and diagrams.

    from langchain.document_loaders import MathpixPDFLoader
    
    loader = MathpixPDFLoader("example_data/math-content.pdf")
    information = loader.load()
    

    PyMuPDFLoader is quick and contains detailed metadata extraction.

    from langchain.document_loaders import PyMuPDFLoader
    
    loader = PyMuPDFLoader("example_data/layout-parser-paper.pdf")
    information = loader.load()
    
    # Optionally move further arguments for PyMuPDF's get_text() name
    information = loader.load(choice="textual content")
    

    PDFMiner Loader is used for extra granular management over textual content extraction.

    from langchain.document_loaders import PDFMinerLoader
    
    loader = PDFMinerLoader("example_data/layout-parser-paper.pdf")
    information = loader.load()
    

    AmazonTextractPDFParser makes use of AWS Textract for OCR and different superior PDF parsing options.

    from langchain.document_loaders import AmazonTextractPDFLoader
    
    # Requires AWS account and configuration
    loader = AmazonTextractPDFLoader("example_data/complex-layout.pdf")
    paperwork = loader.load()
    

    PDFMinerPDFasHTMLLoader generates HTML from PDF for semantic parsing.

    from langchain.document_loaders import PDFMinerPDFasHTMLLoader
    
    loader = PDFMinerPDFasHTMLLoader("example_data/layout-parser-paper.pdf")
    information = loader.load()
    

    PDFPlumberLoader gives detailed metadata and helps one doc per web page.

    from langchain.document_loaders import PDFPlumberLoader
    
    loader = PDFPlumberLoader("example_data/layout-parser-paper.pdf")
    information = loader.load()
    

    Built-in Loaders: LangChain presents all kinds of customized loaders to straight load information out of your apps (equivalent to Slack, Sigma, Notion, Confluence, Google Drive and lots of extra) and databases and use them in LLM functions.

    The entire listing is right here.

    Under are a few examples as an instance this –

    Instance I – Slack

    Slack, a widely-used on the spot messaging platform, may be built-in into LLM workflows and functions.

    • Go to your Slack Workspace Administration web page.
    • Navigate to {your_slack_domain}.slack.com/providers/export.
    • Choose the specified date vary and provoke the export.
    • Slack notifies by way of e-mail and DM as soon as the export is prepared.
    • The export leads to a .zip file situated in your Downloads folder or your designated obtain path.
    • Assign the trail of the downloaded .zip file to LOCAL_ZIPFILE.
    • Use the SlackDirectoryLoader from the langchain.document_loaders package deal.
    from langchain.document_loaders import SlackDirectoryLoader
    
    SLACK_WORKSPACE_URL = "https://xxx.slack.com"  # Change along with your Slack URL
    LOCAL_ZIPFILE = ""  # Path to the Slack zip file
    
    loader = SlackDirectoryLoader(LOCAL_ZIPFILE, SLACK_WORKSPACE_URL)
    docs = loader.load()
    print(docs)
    
    Instance II – Figma

    Figma, a well-liked device for interface design, presents a REST API for information integration.

    • Acquire the Figma file key from the URL format: https://www.figma.com/file/{filekey}/sampleFilename.
    • Node IDs are discovered within the URL parameter ?node-id={node_id}.
    • Generate an entry token following directions on the Figma Assist Middle.
    • The FigmaFileLoader class from langchain.document_loaders.figma is used to load Figma information.
    • Numerous LangChain modules like CharacterTextSplitter, ChatOpenAI, and so forth., are employed for processing.
    import os
    from langchain.document_loaders.figma import FigmaFileLoader
    from langchain.text_splitter import CharacterTextSplitter
    from langchain.chat_models import ChatOpenAI
    from langchain.indexes import VectorstoreIndexCreator
    from langchain.chains import ConversationChain, LLMChain
    from langchain.reminiscence import ConversationBufferWindowMemory
    from langchain.prompts.chat import ChatPromptTemplate, SystemMessagePromptTemplate, AIMessagePromptTemplate, HumanMessagePromptTemplate
    
    figma_loader = FigmaFileLoader(
        os.environ.get("ACCESS_TOKEN"),
        os.environ.get("NODE_IDS"),
        os.environ.get("FILE_KEY"),
    )
    
    index = VectorstoreIndexCreator().from_loaders([figma_loader])
    figma_doc_retriever = index.vectorstore.as_retriever()
    
    • The generate_code operate makes use of the Figma information to create HTML/CSS code.
    • It employs a templated dialog with a GPT-based mannequin.
    def generate_code(human_input):
        # Template for system and human prompts
        system_prompt_template = "Your coding directions..."
        human_prompt_template = "Code the {textual content}. Guarantee it is cellular responsive"
        
        # Creating immediate templates
        system_message_prompt = SystemMessagePromptTemplate.from_template(system_prompt_template)
        human_message_prompt = HumanMessagePromptTemplate.from_template(human_prompt_template)
    
        # Establishing the AI mannequin
        gpt_4 = ChatOpenAI(temperature=0.02, model_name="gpt-4")
    
        # Retrieving related paperwork
        relevant_nodes = figma_doc_retriever.get_relevant_documents(human_input)
    
        # Producing and formatting the immediate
        dialog = [system_message_prompt, human_message_prompt]
        chat_prompt = ChatPromptTemplate.from_messages(dialog)
        response = gpt_4(chat_prompt.format_prompt(context=relevant_nodes, textual content=human_input).to_messages())
    
        return response
    
    # Instance utilization
    response = generate_code("web page prime header")
    print(response.content material)
    
    • The generate_code operate, when executed, returns HTML/CSS code based mostly on the Figma design enter.

    Allow us to now use our information to create just a few doc units.

    We first load a PDF, the BCG annual sustainability report.

    We use the PyPDFLoader for this.

    from langchain.document_loaders import PyPDFLoader
    
    loader = PyPDFLoader("bcg-2022-annual-sustainability-report-apr-2023.pdf")
    pdfpages = loader.load_and_split()
    

    We’ll ingest information from Airtable now. We have now an Airtable containing details about numerous OCR and information extraction fashions –

    Allow us to use the AirtableLoader for this, discovered within the listing of built-in loaders.

    from langchain.document_loaders import AirtableLoader
    
    api_key = "XXXXX"
    base_id = "XXXXX"
    table_id = "XXXXX"
    
    loader = AirtableLoader(api_key, table_id, base_id)
    airtabledocs = loader.load()
    

    Allow us to now proceed and discover ways to use these doc courses.

    Doc Transformers

    Doc transformers in LangChain are important instruments designed to govern paperwork, which we created in our earlier subsection.

    They’re used for duties equivalent to splitting lengthy paperwork into smaller chunks, combining, and filtering, that are essential for adapting paperwork to a mannequin’s context window or assembly particular utility wants.

    One such device is the RecursiveCharacterTextSplitter, a flexible textual content splitter that makes use of a personality listing for splitting. It permits parameters like chunk measurement, overlap, and beginning index. This is an instance of the way it’s utilized in Python:

    from langchain.text_splitter import RecursiveCharacterTextSplitter
    
    state_of_the_union = "Your lengthy textual content right here..."
    
    text_splitter = RecursiveCharacterTextSplitter(
        chunk_size=100,
        chunk_overlap=20,
        length_function=len,
        add_start_index=True,
    )
    
    texts = text_splitter.create_documents([state_of_the_union])
    print(texts[0])
    print(texts[1])
    

    One other device is the CharacterTextSplitter, which splits textual content based mostly on a specified character and contains controls for chunk measurement and overlap:

    from langchain.text_splitter import CharacterTextSplitter
    
    text_splitter = CharacterTextSplitter(
        separator="nn",
        chunk_size=1000,
        chunk_overlap=200,
        length_function=len,
        is_separator_regex=False,
    )
    
    texts = text_splitter.create_documents([state_of_the_union])
    print(texts[0])
    

    The HTMLHeaderTextSplitter is designed to separate HTML content material based mostly on header tags, retaining the semantic construction:

    from langchain.text_splitter import HTMLHeaderTextSplitter
    
    html_string = "Your HTML content material right here..."
    headers_to_split_on = [("h1", "Header 1"), ("h2", "Header 2")]
    
    html_splitter = HTMLHeaderTextSplitter(headers_to_split_on=headers_to_split_on)
    html_header_splits = html_splitter.split_text(html_string)
    print(html_header_splits[0])
    

    A extra complicated manipulation may be achieved by combining HTMLHeaderTextSplitter with one other splitter, just like the Pipelined Splitter:

    from langchain.text_splitter import HTMLHeaderTextSplitter, RecursiveCharacterTextSplitter
    
    url = "https://instance.com"
    headers_to_split_on = [("h1", "Header 1"), ("h2", "Header 2")]
    html_splitter = HTMLHeaderTextSplitter(headers_to_split_on=headers_to_split_on)
    html_header_splits = html_splitter.split_text_from_url(url)
    
    chunk_size = 500
    text_splitter = RecursiveCharacterTextSplitter(chunk_size=chunk_size)
    splits = text_splitter.split_documents(html_header_splits)
    print(splits[0])
    

    LangChain additionally presents particular splitters for various programming languages, just like the Python Code Splitter and the JavaScript Code Splitter:

    from langchain.text_splitter import RecursiveCharacterTextSplitter, Language
    
    python_code = """
    def hello_world():
        print("Howdy, World!")
    hello_world()
    """
    
    python_splitter = RecursiveCharacterTextSplitter.from_language(
        language=Language.PYTHON, chunk_size=50
    )
    python_docs = python_splitter.create_documents([python_code])
    print(python_docs[0])
    
    js_code = """
    operate helloWorld() {
      console.log("Howdy, World!");
    }
    helloWorld();
    """
    
    js_splitter = RecursiveCharacterTextSplitter.from_language(
        language=Language.JS, chunk_size=60
    )
    js_docs = js_splitter.create_documents([js_code])
    print(js_docs[0])
    

    For splitting textual content based mostly on token rely, which is helpful for language fashions with token limits, the TokenTextSplitter is used:

    from langchain.text_splitter import TokenTextSplitter
    
    text_splitter = TokenTextSplitter(chunk_size=10)
    texts = text_splitter.split_text(state_of_the_union)
    print(texts[0])
    

    Lastly, the LongContextReorder reorders paperwork to forestall efficiency degradation in fashions as a consequence of lengthy contexts:

    from langchain.document_transformers import LongContextReorder
    
    reordering = LongContextReorder()
    reordered_docs = reordering.transform_documents(docs)
    print(reordered_docs[0])
    

    These instruments display numerous methods to rework paperwork in LangChain, from easy textual content splitting to complicated reordering and language-specific splitting. For extra in-depth and particular use instances, the LangChain documentation and Integrations part needs to be consulted.

    In our examples, the loaders have already created chunked paperwork for us, and this half is already dealt with.

    Textual content Embedding Fashions

    Textual content embedding fashions in LangChain present a standardized interface for numerous embedding mannequin suppliers like OpenAI, Cohere, and Hugging Face. These fashions rework textual content into vector representations, enabling operations like semantic search by way of textual content similarity in vector area.

    To get began with textual content embedding fashions, you sometimes want to put in particular packages and arrange API keys. We have now already completed this for OpenAI

    In LangChain, the embed_documents technique is used to embed a number of texts, offering an inventory of vector representations. As an example:

    from langchain.embeddings import OpenAIEmbeddings
    
    # Initialize the mannequin
    embeddings_model = OpenAIEmbeddings()
    
    # Embed an inventory of texts
    embeddings = embeddings_model.embed_documents(
        ["Hi there!", "Oh, hello!", "What's your name?", "My friends call me World", "Hello World!"]
    )
    print("Variety of paperwork embedded:", len(embeddings))
    print("Dimension of every embedding:", len(embeddings[0]))
    

    For embedding a single textual content, equivalent to a search question, the embed_query technique is used. That is helpful for evaluating a question to a set of doc embeddings. For instance:

    from langchain.embeddings import OpenAIEmbeddings
    
    # Initialize the mannequin
    embeddings_model = OpenAIEmbeddings()
    
    # Embed a single question
    embedded_query = embeddings_model.embed_query("What was the identify talked about within the dialog?")
    print("First 5 dimensions of the embedded question:", embedded_query[:5])
    

    Understanding these embeddings is essential. Each bit of textual content is transformed right into a vector, the dimension of which is determined by the mannequin used. As an example, OpenAI fashions sometimes produce 1536-dimensional vectors. These embeddings are then used for retrieving related info.

    LangChain’s embedding performance shouldn’t be restricted to OpenAI however is designed to work with numerous suppliers. The setup and utilization would possibly barely differ relying on the supplier, however the core idea of embedding texts into vector area stays the identical. For detailed utilization, together with superior configurations and integrations with totally different embedding mannequin suppliers, the LangChain documentation within the Integrations part is a priceless useful resource.

    Vector Shops

    Vector shops in LangChain assist the environment friendly storage and looking out of textual content embeddings. LangChain integrates with over 50 vector shops, offering a standardized interface for ease of use.

    Instance: Storing and Looking Embeddings

    After embedding texts, we are able to retailer them in a vector retailer like Chroma and carry out similarity searches:

    from langchain.vectorstores import Chroma
    
    db = Chroma.from_texts(embedded_texts)
    similar_texts = db.similarity_search("search question")
    

    Allow us to alternatively use the FAISS vector retailer to create indexes for our paperwork.

    from langchain.embeddings import OpenAIEmbeddings
    from langchain.vectorstores import FAISS
    
    pdfstore = FAISS.from_documents(pdfpages, 
                embedding=OpenAIEmbeddings())
    
    airtablestore = FAISS.from_documents(airtabledocs, 
                embedding=OpenAIEmbeddings())
    

    Retrievers

    Retrievers in LangChain are interfaces that return paperwork in response to an unstructured question. They’re extra basic than vector shops, specializing in retrieval moderately than storage. Though vector shops can be utilized as a retriever’s spine, there are different kinds of retrievers as effectively.

    To arrange a Chroma retriever, you first set up it utilizing pip set up chromadb. Then, you load, cut up, embed, and retrieve paperwork utilizing a sequence of Python instructions. This is a code instance for establishing a Chroma retriever:

    from langchain.embeddings import OpenAIEmbeddings
    from langchain.text_splitter import CharacterTextSplitter
    from langchain.vectorstores import Chroma
    
    full_text = open("state_of_the_union.txt", "r").learn()
    text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=100)
    texts = text_splitter.split_text(full_text)
    
    embeddings = OpenAIEmbeddings()
    db = Chroma.from_texts(texts, embeddings)
    retriever = db.as_retriever()
    
    retrieved_docs = retriever.invoke("What did the president say about Ketanji Brown Jackson?")
    print(retrieved_docs[0].page_content)
    

    The MultiQueryRetriever automates immediate tuning by producing a number of queries for a person enter question and combines the outcomes. This is an instance of its easy utilization:

    from langchain.chat_models import ChatOpenAI
    from langchain.retrievers.multi_query import MultiQueryRetriever
    
    query = "What are the approaches to Job Decomposition?"
    llm = ChatOpenAI(temperature=0)
    retriever_from_llm = MultiQueryRetriever.from_llm(
        retriever=db.as_retriever(), llm=llm
    )
    
    unique_docs = retriever_from_llm.get_relevant_documents(question=query)
    print("Variety of distinctive paperwork:", len(unique_docs))
    

    Contextual Compression in LangChain compresses retrieved paperwork utilizing the context of the question, guaranteeing solely related info is returned. This entails content material discount and filtering out much less related paperwork. The next code instance reveals how one can use Contextual Compression Retriever:

    from langchain.llms import OpenAI
    from langchain.retrievers import ContextualCompressionRetriever
    from langchain.retrievers.document_compressors import LLMChainExtractor
    
    llm = OpenAI(temperature=0)
    compressor = LLMChainExtractor.from_llm(llm)
    compression_retriever = ContextualCompressionRetriever(base_compressor=compressor, base_retriever=retriever)
    
    compressed_docs = compression_retriever.get_relevant_documents("What did the president say about Ketanji Jackson Brown")
    print(compressed_docs[0].page_content)
    

    The EnsembleRetriever combines totally different retrieval algorithms to realize higher efficiency. An instance of mixing BM25 and FAISS Retrievers is proven within the following code:

    from langchain.retrievers import BM25Retriever, EnsembleRetriever
    from langchain.vectorstores import FAISS
    
    bm25_retriever = BM25Retriever.from_texts(doc_list).set_k(2)
    faiss_vectorstore = FAISS.from_texts(doc_list, OpenAIEmbeddings())
    faiss_retriever = faiss_vectorstore.as_retriever(search_kwargs={"ok": 2})
    
    ensemble_retriever = EnsembleRetriever(
        retrievers=[bm25_retriever, faiss_retriever], weights=[0.5, 0.5]
    )
    
    docs = ensemble_retriever.get_relevant_documents("apples")
    print(docs[0].page_content)
    

    MultiVector Retriever in LangChain permits querying paperwork with a number of vectors per doc, which is helpful for capturing totally different semantic facets inside a doc. Strategies for creating a number of vectors embrace splitting into smaller chunks, summarizing, or producing hypothetical questions. For splitting paperwork into smaller chunks, the next Python code can be utilized:

    
    python
    from langchain.retrievers.multi_vector import MultiVectorRetriever
    from langchain.vectorstores import Chroma
    from langchain.embeddings import OpenAIEmbeddings
    from langchain.text_splitter import RecursiveCharacterTextSplitter
    from langchain.storage import InMemoryStore
    from langchain.document_loaders from TextLoader
    import uuid
    
    loaders = [TextLoader("file1.txt"), TextLoader("file2.txt")]
    docs = [doc for loader in loaders for doc in loader.load()]
    text_splitter = RecursiveCharacterTextSplitter(chunk_size=10000)
    docs = text_splitter.split_documents(docs)
    
    vectorstore = Chroma(collection_name="full_documents", embedding_function=OpenAIEmbeddings())
    retailer = InMemoryStore()
    id_key = "doc_id"
    retriever = MultiVectorRetriever(vectorstore=vectorstore, docstore=retailer, id_key=id_key)
    
    doc_ids = [str(uuid.uuid4()) for _ in docs]
    child_text_splitter = RecursiveCharacterTextSplitter(chunk_size=400)
    sub_docs = [sub_doc for doc in docs for sub_doc in child_text_splitter.split_documents([doc])]
    for sub_doc in sub_docs:
        sub_doc.metadata[id_key] = doc_ids[sub_docs.index(sub_doc)]
    
    retriever.vectorstore.add_documents(sub_docs)
    retriever.docstore.mset(listing(zip(doc_ids, docs)))
    

    Producing summaries for higher retrieval as a consequence of extra targeted content material illustration is one other technique. This is an instance of producing summaries:

    from langchain.chat_models import ChatOpenAI
    from langchain.prompts import ChatPromptTemplate
    from langchain.schema.output_parser import StrOutputParser
    from langchain.schema.doc import Doc
    
    chain = (lambda x: x.page_content) | ChatPromptTemplate.from_template("Summarize the next doc:nn{doc}") | ChatOpenAI(max_retries=0) | StrOutputParser()
    summaries = chain.batch(docs, {"max_concurrency": 5})
    
    summary_docs = [Document(page_content=s, metadata={id_key: doc_ids[i]}) for i, s in enumerate(summaries)]
    retriever.vectorstore.add_documents(summary_docs)
    retriever.docstore.mset(listing(zip(doc_ids, docs)))
    

    Producing hypothetical questions related to every doc utilizing LLM is one other method. This may be completed with the next code:

    features = [{"name": "hypothetical_questions", "parameters": {"questions": {"type": "array", "items": {"type": "string"}}}}]
    from langchain.output_parsers.openai_functions import JsonKeyOutputFunctionsParser
    
    chain = (lambda x: x.page_content) | ChatPromptTemplate.from_template("Generate 3 hypothetical questions:nn{doc}") | ChatOpenAI(max_retries=0).bind(features=features, function_call={"identify": "hypothetical_questions"}) | JsonKeyOutputFunctionsParser(key_name="questions")
    hypothetical_questions = chain.batch(docs, {"max_concurrency": 5})
    
    question_docs = [Document(page_content=q, metadata={id_key: doc_ids[i]}) for i, questions in enumerate(hypothetical_questions) for q in questions]
    retriever.vectorstore.add_documents(question_docs)
    retriever.docstore.mset(listing(zip(doc_ids, docs)))
    

    The Dad or mum Doc Retriever is one other retriever that strikes a stability between embedding accuracy and context retention by storing small chunks and retrieving their bigger father or mother paperwork. Its implementation is as follows:

    from langchain.retrievers import ParentDocumentRetriever
    
    loaders = [TextLoader("file1.txt"), TextLoader("file2.txt")]
    docs = [doc for loader in loaders for doc in loader.load()]
    
    child_splitter = RecursiveCharacterTextSplitter(chunk_size=400)
    vectorstore = Chroma(collection_name="full_documents", embedding_function=OpenAIEmbeddings())
    retailer = InMemoryStore()
    retriever = ParentDocumentRetriever(vectorstore=vectorstore, docstore=retailer, child_splitter=child_splitter)
    
    retriever.add_documents(docs, ids=None)
    
    retrieved_docs = retriever.get_relevant_documents("question")
    

    A self-querying retriever constructs structured queries from pure language inputs and applies them to its underlying VectorStore. Its implementation is proven within the following code:

    from langchain.chat_models from ChatOpenAI
    from langchain.chains.query_constructor.base from AttributeInfo
    from langchain.retrievers.self_query.base from SelfQueryRetriever
    
    metadata_field_info = [AttributeInfo(name="genre", description="...", type="string"), ...]
    document_content_description = "Transient abstract of a film"
    llm = ChatOpenAI(temperature=0)
    
    retriever = SelfQueryRetriever.from_llm(llm, vectorstore, document_content_description, metadata_field_info)
    
    retrieved_docs = retriever.invoke("question")
    

    The WebResearchRetriever performs net analysis based mostly on a given question –

    from langchain.retrievers.web_research import WebResearchRetriever
    
    # Initialize elements
    llm = ChatOpenAI(temperature=0)
    search = GoogleSearchAPIWrapper()
    vectorstore = Chroma(embedding_function=OpenAIEmbeddings())
    
    # Instantiate WebResearchRetriever
    web_research_retriever = WebResearchRetriever.from_llm(vectorstore=vectorstore, llm=llm, search=search)
    
    # Retrieve paperwork
    docs = web_research_retriever.get_relevant_documents("question")
    

    For our examples, we are able to additionally use the usual retriever already carried out as a part of our vector retailer object as follows –

    We will now question the retrievers. The output of our question shall be doc objects related to the question. These shall be in the end utilized to create related responses in additional sections.


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    Module III : Brokers

    LangChain introduces a strong idea known as “Brokers” that takes the concept of chains to a complete new degree. Brokers leverage language fashions to dynamically decide sequences of actions to carry out, making them extremely versatile and adaptive. Not like conventional chains, the place actions are hardcoded in code, brokers make use of language fashions as reasoning engines to resolve which actions to take and in what order.

    The Agent is the core part chargeable for decision-making. It harnesses the facility of a language mannequin and a immediate to find out the following steps to realize a particular goal. The inputs to an agent sometimes embrace:

    • Instruments: Descriptions of obtainable instruments (extra on this later).
    • Person Enter: The high-level goal or question from the person.
    • Intermediate Steps: A historical past of (motion, device output) pairs executed to succeed in the present person enter.

    The output of an agent may be the following motion to take actions (AgentActions) or the ultimate response to ship to the person (AgentFinish). An motion specifies a device and the enter for that device.


    Instruments

    Instruments are interfaces that an agent can use to work together with the world. They allow brokers to carry out numerous duties, equivalent to looking out the online, operating shell instructions, or accessing exterior APIs. In LangChain, instruments are important for extending the capabilities of brokers and enabling them to perform various duties.

    To make use of instruments in LangChain, you may load them utilizing the next snippet:

    from langchain.brokers import load_tools
    
    tool_names = [...]
    instruments = load_tools(tool_names)
    

    Some instruments might require a base Language Mannequin (LLM) to initialize. In such instances, you may move an LLM as effectively:

    from langchain.brokers import load_tools
    
    tool_names = [...]
    llm = ...
    instruments = load_tools(tool_names, llm=llm)
    

    This setup means that you can entry quite a lot of instruments and combine them into your agent’s workflows. The entire listing of instruments with utilization documentation is right here.

    Allow us to take a look at some examples of Instruments.

    DuckDuckGo

    The DuckDuckGo device allows you to carry out net searches utilizing its search engine. This is how one can use it:

    from langchain.instruments import DuckDuckGoSearchRun
    search = DuckDuckGoSearchRun()
    search.run("manchester united vs luton city match abstract")
    
    DataForSeo

    The DataForSeo toolkit means that you can get hold of search engine outcomes utilizing the DataForSeo API. To make use of this toolkit, you may have to arrange your API credentials. This is how one can configure the credentials:

    import os
    
    os.environ["DATAFORSEO_LOGIN"] = "<your_api_access_username>"
    os.environ["DATAFORSEO_PASSWORD"] = "<your_api_access_password>"
    

    As soon as your credentials are set, you may create a DataForSeoAPIWrapper device to entry the API:

    from langchain.utilities.dataforseo_api_search import DataForSeoAPIWrapper
    
    wrapper = DataForSeoAPIWrapper()
    
    end result = wrapper.run("Climate in Los Angeles")
    

    The DataForSeoAPIWrapper device retrieves search engine outcomes from numerous sources.

    You’ll be able to customise the kind of outcomes and fields returned within the JSON response. For instance, you may specify the end result varieties, fields, and set a most rely for the variety of prime outcomes to return:

    json_wrapper = DataForSeoAPIWrapper(
        json_result_types=["organic", "knowledge_graph", "answer_box"],
        json_result_fields=["type", "title", "description", "text"],
        top_count=3,
    )
    
    json_result = json_wrapper.outcomes("Invoice Gates")
    

    This instance customizes the JSON response by specifying end result varieties, fields, and limiting the variety of outcomes.

    You may also specify the situation and language to your search outcomes by passing further parameters to the API wrapper:

    customized_wrapper = DataForSeoAPIWrapper(
        top_count=10,
        json_result_types=["organic", "local_pack"],
        json_result_fields=["title", "description", "type"],
        params={"location_name": "Germany", "language_code": "en"},
    )
    
    customized_result = customized_wrapper.outcomes("espresso close to me")
    

    By offering location and language parameters, you may tailor your search outcomes to particular areas and languages.

    You’ve got the pliability to decide on the search engine you need to use. Merely specify the specified search engine:

    customized_wrapper = DataForSeoAPIWrapper(
        top_count=10,
        json_result_types=["organic", "local_pack"],
        json_result_fields=["title", "description", "type"],
        params={"location_name": "Germany", "language_code": "en", "se_name": "bing"},
    )
    
    customized_result = customized_wrapper.outcomes("espresso close to me")
    

    On this instance, the search is personalized to make use of Bing because the search engine.

    The API wrapper additionally means that you can specify the kind of search you need to carry out. As an example, you may carry out a maps search:

    maps_search = DataForSeoAPIWrapper(
        top_count=10,
        json_result_fields=["title", "value", "address", "rating", "type"],
        params={
            "location_coordinate": "52.512,13.36,12z",
            "language_code": "en",
            "se_type": "maps",
        },
    )
    
    maps_search_result = maps_search.outcomes("espresso close to me")
    

    This customizes the search to retrieve maps-related info.

    Shell (bash)

    The Shell toolkit gives brokers with entry to the shell setting, permitting them to execute shell instructions. This function is highly effective however needs to be used with warning, particularly in sandboxed environments. This is how you should utilize the Shell device:

    from langchain.instruments import ShellTool
    
    shell_tool = ShellTool()
    
    end result = shell_tool.run({"instructions": ["echo 'Hello World!'", "time"]})
    

    On this instance, the Shell device runs two shell instructions: echoing “Howdy World!” and displaying the present time.

    You’ll be able to present the Shell device to an agent to carry out extra complicated duties. This is an instance of an agent fetching hyperlinks from an online web page utilizing the Shell device:

    from langchain.brokers import AgentType, initialize_agent
    from langchain.chat_models import ChatOpenAI
    
    llm = ChatOpenAI(temperature=0.1)
    
    shell_tool.description = shell_tool.description + f"args {shell_tool.args}".change(
        "{", "{{"
    ).change("}", "}}")
    self_ask_with_search = initialize_agent(
        [shell_tool], llm, agent=AgentType.CHAT_ZERO_SHOT_REACT_DESCRIPTION, verbose=True
    )
    self_ask_with_search.run(
        "Obtain the langchain.com webpage and grep for all urls. Return solely a sorted listing of them. Remember to use double quotes."
    )

    On this state of affairs, the agent makes use of the Shell device to execute a sequence of instructions to fetch, filter, and kind URLs from an online web page.

    The examples offered display among the instruments accessible in LangChain. These instruments in the end prolong the capabilities of brokers (explored in subsequent subsection) and empower them to carry out numerous duties effectively. Relying in your necessities, you may select the instruments and toolkits that greatest fit your undertaking’s wants and combine them into your agent’s workflows.

    Again to Brokers

    Let’s transfer on to brokers now.

    The AgentExecutor is the runtime setting for an agent. It’s chargeable for calling the agent, executing the actions it selects, passing the motion outputs again to the agent, and repeating the method till the agent finishes. In pseudocode, the AgentExecutor would possibly look one thing like this:

    next_action = agent.get_action(...)
    whereas next_action != AgentFinish:
        commentary = run(next_action)
        next_action = agent.get_action(..., next_action, commentary)
    return next_action
    

    The AgentExecutor handles numerous complexities, equivalent to coping with instances the place the agent selects a non-existent device, dealing with device errors, managing agent-produced outputs, and offering logging and observability in any respect ranges.

    Whereas the AgentExecutor class is the first agent runtime in LangChain, there are different, extra experimental runtimes supported, together with:

    • Plan-and-execute Agent
    • Child AGI
    • Auto GPT

    To achieve a greater understanding of the agent framework, let’s construct a fundamental agent from scratch, after which transfer on to discover pre-built brokers.

    Earlier than we dive into constructing the agent, it is important to revisit some key terminology and schema:

    • AgentAction: This can be a information class representing the motion an agent ought to take. It consists of a device property (the identify of the device to invoke) and a tool_input property (the enter for that device).
    • AgentFinish: This information class signifies that the agent has completed its process and may return a response to the person. It sometimes features a dictionary of return values, typically with a key “output” containing the response textual content.
    • Intermediate Steps: These are the data of earlier agent actions and corresponding outputs. They’re essential for passing context to future iterations of the agent.

    In our instance, we are going to use OpenAI Perform Calling to create our agent. This method is dependable for agent creation. We’ll begin by making a easy device that calculates the size of a phrase. This device is helpful as a result of language fashions can typically make errors as a consequence of tokenization when counting phrase lengths.

    First, let’s load the language mannequin we’ll use to regulate the agent:

    from langchain.chat_models import ChatOpenAI
    
    llm = ChatOpenAI(mannequin="gpt-3.5-turbo", temperature=0)
    

    Let’s check the mannequin with a phrase size calculation:

    llm.invoke("what number of letters within the phrase educa?")
    

    The response ought to point out the variety of letters within the phrase “educa.”

    Subsequent, we’ll outline a easy Python operate to calculate the size of a phrase:

    from langchain.brokers import device
    
    @device
    def get_word_length(phrase: str) -> int:
        """Returns the size of a phrase."""
        return len(phrase)
    

    We have created a device named get_word_length that takes a phrase as enter and returns its size.

    Now, let’s create the immediate for the agent. The immediate instructs the agent on how one can purpose and format the output. In our case, we’re utilizing OpenAI Perform Calling, which requires minimal directions. We’ll outline the immediate with placeholders for person enter and agent scratchpad:

    from langchain.prompts import ChatPromptTemplate, MessagesPlaceholder
    
    immediate = ChatPromptTemplate.from_messages(
        [
            (
                "system",
                "You are a very powerful assistant but not great at calculating word lengths.",
            ),
            ("user", "{input}"),
            MessagesPlaceholder(variable_name="agent_scratchpad"),
        ]
    )
    

    Now, how does the agent know which instruments it could use? We’re counting on OpenAI operate calling language fashions, which require features to be handed individually. To supply our instruments to the agent, we’ll format them as OpenAI operate calls:

    from langchain.instruments.render import format_tool_to_openai_function
    
    llm_with_tools = llm.bind(features=[format_tool_to_openai_function(t) for t in tools])
    

    Now, we are able to create the agent by defining enter mappings and connecting the elements:

    That is LCEL language. We’ll focus on this later intimately.

    from langchain.brokers.format_scratchpad import format_to_openai_function_messages
    from langchain.brokers.output_parsers import OpenAIFunctionsAgentOutputParser
    
    agent = (
        {
            "enter": lambda x: x["input"],
            "agent_scratchpad": lambda x: format_to_openai
    
    _function_messages(
                x["intermediate_steps"]
            ),
        }
        | immediate
        | llm_with_tools
        | OpenAIFunctionsAgentOutputParser()
    )
    

    We have created our agent, which understands person enter, makes use of accessible instruments, and codecs output. Now, let’s work together with it:

    agent.invoke({"enter": "what number of letters within the phrase educa?", "intermediate_steps": []})
    

    The agent ought to reply with an AgentAction, indicating the following motion to take.

    We have created the agent, however now we have to write a runtime for it. The only runtime is one which repeatedly calls the agent, executes actions, and repeats till the agent finishes. This is an instance:

    from langchain.schema.agent import AgentFinish
    
    user_input = "what number of letters within the phrase educa?"
    intermediate_steps = []
    
    whereas True:
        output = agent.invoke(
            {
                "enter": user_input,
                "intermediate_steps": intermediate_steps,
            }
        )
        if isinstance(output, AgentFinish):
            final_result = output.return_values["output"]
            break
        else:
            print(f"TOOL NAME: {output.device}")
            print(f"TOOL INPUT: {output.tool_input}")
            device = {"get_word_length": get_word_length}[output.tool]
            commentary = device.run(output.tool_input)
            intermediate_steps.append((output, commentary))
    
    print(final_result)
    

    On this loop, we repeatedly name the agent, execute actions, and replace the intermediate steps till the agent finishes. We additionally deal with device interactions throughout the loop.

    To simplify this course of, LangChain gives the AgentExecutor class, which encapsulates agent execution and presents error dealing with, early stopping, tracing, and different enhancements. Let’s use AgentExecutor to work together with the agent:

    from langchain.brokers import AgentExecutor
    
    agent_executor = AgentExecutor(agent=agent, instruments=instruments, verbose=True)
    
    agent_executor.invoke({"enter": "what number of letters within the phrase educa?"})
    

    AgentExecutor simplifies the execution course of and gives a handy solution to work together with the agent.

    Reminiscence can be mentioned intimately later.

    The agent we have created to this point is stateless, that means it would not keep in mind earlier interactions. To allow follow-up questions and conversations, we have to add reminiscence to the agent. This entails two steps:

    1. Add a reminiscence variable within the immediate to retailer chat historical past.
    2. Hold monitor of the chat historical past throughout interactions.

    Let’s begin by including a reminiscence placeholder within the immediate:

    from langchain.prompts import MessagesPlaceholder
    
    MEMORY_KEY = "chat_history"
    immediate = ChatPromptTemplate.from_messages(
        [
            (
                "system",
                "You are a very powerful assistant but not great at calculating word lengths.",
            ),
            MessagesPlaceholder(variable_name=MEMORY_KEY),
            ("user", "{input}"),
            MessagesPlaceholder(variable_name="agent_scratchpad"),
        ]
    )
    

    Now, create an inventory to trace the chat historical past:

    from langchain.schema.messages import HumanMessage, AIMessage
    
    chat_history = []
    

    Within the agent creation step, we’ll embrace the reminiscence as effectively:

    agent = (
        {
            "enter": lambda x: x["input"],
            "agent_scratchpad": lambda x: format_to_openai_function_messages(
                x["intermediate_steps"]
            ),
            "chat_history": lambda x: x["chat_history"],
        }
        | immediate
        | llm_with_tools
        | OpenAIFunctionsAgentOutputParser()
    )
    

    Now, when operating the agent, make sure that to replace the chat historical past:

    input1 = "what number of letters within the phrase educa?"
    end result = agent_executor.invoke({"enter": input1, "chat_history": chat_history})
    chat_history.prolong([
        HumanMessage(content=input1),
        AIMessage(content=result["output"]),
    ])
    agent_executor.invoke({"enter": "is that an actual phrase?", "chat_history": chat_history})
    

    This allows the agent to take care of a dialog historical past and reply follow-up questions based mostly on earlier interactions.

    Congratulations! You’ve got efficiently created and executed your first end-to-end agent in LangChain. To delve deeper into LangChain’s capabilities, you may discover:

    • Totally different agent varieties supported.
    • Pre-built Brokers
    • The best way to work with instruments and power integrations.
    Agent Varieties

    LangChain presents numerous agent varieties, every suited to particular use instances. Listed here are among the accessible brokers:

    • Zero-shot ReAct: This agent makes use of the ReAct framework to decide on instruments based mostly solely on their descriptions. It requires descriptions for every device and is very versatile.
    • Structured enter ReAct: This agent handles multi-input instruments and is appropriate for complicated duties like navigating an online browser. It makes use of a instruments’ argument schema for structured enter.
    • OpenAI Features: Particularly designed for fashions fine-tuned for operate calling, this agent is suitable with fashions like gpt-3.5-turbo-0613 and gpt-4-0613. We used this to create our first agent above.
    • Conversational: Designed for conversational settings, this agent makes use of ReAct for device choice and makes use of reminiscence to recollect earlier interactions.
    • Self-ask with search: This agent depends on a single device, “Intermediate Reply,” which seems up factual solutions to questions. It is equal to the unique self-ask with search paper.
    • ReAct doc retailer: This agent interacts with a doc retailer utilizing the ReAct framework. It requires “Search” and “Lookup” instruments and is just like the unique ReAct paper’s Wikipedia instance.

    Discover these agent varieties to search out the one which most closely fits your wants in LangChain. These brokers assist you to bind set of instruments inside them to deal with actions and generate responses. Be taught extra on how one can construct your individual agent with instruments right here.

    Prebuilt Brokers

    Let’s proceed our exploration of brokers, specializing in prebuilt brokers accessible in LangChain.

    Gmail

    LangChain presents a Gmail toolkit that means that you can join your LangChain e-mail to the Gmail API. To get began, you may have to arrange your credentials, that are defined within the Gmail API documentation. After getting downloaded the credentials.json file, you may proceed with utilizing the Gmail API. Moreover, you may want to put in some required libraries utilizing the next instructions:

    pip set up --upgrade google-api-python-client > /dev/null
    pip set up --upgrade google-auth-oauthlib > /dev/null
    pip set up --upgrade google-auth-httplib2 > /dev/null
    pip set up beautifulsoup4 > /dev/null  # Elective for parsing HTML messages
    

    You’ll be able to create the Gmail toolkit as follows:

    from langchain.brokers.agent_toolkits import GmailToolkit
    
    toolkit = GmailToolkit()
    

    You may also customise authentication as per your wants. Behind the scenes, a googleapi useful resource is created utilizing the next strategies:

    from langchain.instruments.gmail.utils import build_resource_service, get_gmail_credentials
    
    credentials = get_gmail_credentials(
        token_file="token.json",
        scopes=["https://mail.google.com/"],
        client_secrets_file="credentials.json",
    )
    api_resource = build_resource_service(credentials=credentials)
    toolkit = GmailToolkit(api_resource=api_resource)
    

    The toolkit presents numerous instruments that can be utilized inside an agent, together with:

    • GmailCreateDraft: Create a draft e-mail with specified message fields.
    • GmailSendMessage: Ship e-mail messages.
    • GmailSearch: Seek for e-mail messages or threads.
    • GmailGetMessage: Fetch an e-mail by message ID.
    • GmailGetThread: Seek for e-mail messages.

    To make use of these instruments inside an agent, you may initialize the agent as follows:

    from langchain.llms import OpenAI
    from langchain.brokers import initialize_agent, AgentType
    
    llm = OpenAI(temperature=0)
    agent = initialize_agent(
        instruments=toolkit.get_tools(),
        llm=llm,
        agent=AgentType.STRUCTURED_CHAT_ZERO_SHOT_REACT_DESCRIPTION,
    )
    

    Listed here are a few examples of how these instruments can be utilized:

    1. Create a Gmail draft for enhancing:
    agent.run(
        "Create a gmail draft for me to edit of a letter from the attitude of a sentient parrot "
        "who's seeking to collaborate on some analysis along with her estranged pal, a cat. "
        "On no account might you ship the message, nonetheless."
    )
    
    1. Seek for the newest e-mail in your drafts:
    agent.run("Might you search in my drafts for the newest e-mail?")
    

    These examples display the capabilities of LangChain’s Gmail toolkit inside an agent, enabling you to work together with Gmail programmatically.

    SQL Database Agent

    This part gives an outline of an agent designed to work together with SQL databases, significantly the Chinook database. This agent can reply basic questions on a database and get well from errors. Please word that it’s nonetheless in energetic improvement, and never all solutions could also be appropriate. Be cautious when operating it on delicate information, as it might carry out DML statements in your database.

    To make use of this agent, you may initialize it as follows:

    from langchain.brokers import create_sql_agent
    from langchain.brokers.agent_toolkits import SQLDatabaseToolkit
    from langchain.sql_database import SQLDatabase
    from langchain.llms.openai import OpenAI
    from langchain.brokers import AgentExecutor
    from langchain.brokers.agent_types import AgentType
    from langchain.chat_models import ChatOpenAI
    
    db = SQLDatabase.from_uri("sqlite:///../../../../../notebooks/Chinook.db")
    toolkit = SQLDatabaseToolkit(db=db, llm=OpenAI(temperature=0))
    
    agent_executor = create_sql_agent(
        llm=OpenAI(temperature=0),
        toolkit=toolkit,
        verbose=True,
        agent_type=AgentType.ZERO_SHOT_REACT_DESCRIPTION,
    )
    

    This agent may be initialized utilizing the ZERO_SHOT_REACT_DESCRIPTION agent sort. It’s designed to reply questions and supply descriptions. Alternatively, you may initialize the agent utilizing the OPENAI_FUNCTIONS agent sort with OpenAI’s GPT-3.5-turbo mannequin, which we utilized in our earlier shopper.


    Disclaimer

    • The question chain might generate insert/replace/delete queries. Be cautious, and use a customized immediate or create a SQL person with out write permissions if wanted.
    • Remember that operating sure queries, equivalent to “run the largest question doable,” may overload your SQL database, particularly if it accommodates thousands and thousands of rows.
    • Information warehouse-oriented databases typically assist user-level quotas to restrict useful resource utilization.

    You’ll be able to ask the agent to explain a desk, such because the “playlisttrack” desk. This is an instance of how one can do it:

    agent_executor.run("Describe the playlisttrack desk")
    

    The agent will present details about the desk’s schema and pattern rows.

    For those who mistakenly ask a couple of desk that does not exist, the agent can get well and supply details about the closest matching desk. For instance:

    agent_executor.run("Describe the playlistsong desk")
    

    The agent will discover the closest matching desk and supply details about it.

    You may also ask the agent to run queries on the database. As an example:

    agent_executor.run("Record the full gross sales per nation. Which nation's clients spent probably the most?")
    

    The agent will execute the question and supply the end result, such because the nation with the very best complete gross sales.

    To get the full variety of tracks in every playlist, you should utilize the next question:

    agent_executor.run("Present the full variety of tracks in every playlist. The Playlist identify needs to be included within the end result.")
    

    The agent will return the playlist names together with the corresponding complete monitor counts.

    In instances the place the agent encounters errors, it could get well and supply correct responses. As an example:

    agent_executor.run("Who're the highest 3 greatest promoting artists?")
    

    Even after encountering an preliminary error, the agent will alter and supply the right reply, which, on this case, is the highest 3 best-selling artists.

    Pandas DataFrame Agent

    This part introduces an agent designed to work together with Pandas DataFrames for question-answering functions. Please word that this agent makes use of the Python agent below the hood to execute Python code generated by a language mannequin (LLM). Train warning when utilizing this agent to forestall potential hurt from malicious Python code generated by the LLM.

    You’ll be able to initialize the Pandas DataFrame agent as follows:

    from langchain_experimental.brokers.agent_toolkits import create_pandas_dataframe_agent
    from langchain.chat_models import ChatOpenAI
    from langchain.brokers.agent_types import AgentType
    
    from langchain.llms import OpenAI
    import pandas as pd
    
    df = pd.read_csv("titanic.csv")
    
    # Utilizing ZERO_SHOT_REACT_DESCRIPTION agent sort
    agent = create_pandas_dataframe_agent(OpenAI(temperature=0), df, verbose=True)
    
    # Alternatively, utilizing OPENAI_FUNCTIONS agent sort
    # agent = create_pandas_dataframe_agent(
    #     ChatOpenAI(temperature=0, mannequin="gpt-3.5-turbo-0613"),
    #     df,
    #     verbose=True,
    #     agent_type=AgentType.OPENAI_FUNCTIONS,
    # )
    

    You’ll be able to ask the agent to rely the variety of rows within the DataFrame:

    agent.run("what number of rows are there?")
    

    The agent will execute the code df.form[0] and supply the reply, equivalent to “There are 891 rows within the dataframe.”

    You may also ask the agent to filter rows based mostly on particular standards, equivalent to discovering the variety of folks with greater than 3 siblings:

    agent.run("how many individuals have greater than 3 siblings")
    

    The agent will execute the code df[df['SibSp'] > 3].form[0] and supply the reply, equivalent to “30 folks have greater than 3 siblings.”

    If you wish to calculate the sq. root of the typical age, you may ask the agent:

    agent.run("whats the sq. root of the typical age?")
    

    The agent will calculate the typical age utilizing df['Age'].imply() after which calculate the sq. root utilizing math.sqrt(). It would present the reply, equivalent to “The sq. root of the typical age is 5.449689683556195.”

    Let’s create a replica of the DataFrame, and lacking age values are full of the imply age:

    df1 = df.copy()
    df1["Age"] = df1["Age"].fillna(df1["Age"].imply())
    

    Then, you may initialize the agent with each DataFrames and ask it a query:

    agent = create_pandas_dataframe_agent(OpenAI(temperature=0), [df, df1], verbose=True)
    agent.run("what number of rows within the age column are totally different?")
    

    The agent will examine the age columns in each DataFrames and supply the reply, equivalent to “177 rows within the age column are totally different.”

    Jira Toolkit

    This part explains how one can use the Jira toolkit, which permits brokers to work together with a Jira occasion. You’ll be able to carry out numerous actions equivalent to trying to find points and creating points utilizing this toolkit. It makes use of the atlassian-python-api library. To make use of this toolkit, it’s worthwhile to set setting variables to your Jira occasion, together with JIRA_API_TOKEN, JIRA_USERNAME, and JIRA_INSTANCE_URL. Moreover, you might have to set your OpenAI API key as an setting variable.

    To get began, set up the atlassian-python-api library and set the required setting variables:

    %pip set up atlassian-python-api
    
    import os
    from langchain.brokers import AgentType
    from langchain.brokers import initialize_agent
    from langchain.brokers.agent_toolkits.jira.toolkit import JiraToolkit
    from langchain.llms import OpenAI
    from langchain.utilities.jira import JiraAPIWrapper
    
    os.environ["JIRA_API_TOKEN"] = "abc"
    os.environ["JIRA_USERNAME"] = "123"
    os.environ["JIRA_INSTANCE_URL"] = "https://jira.atlassian.com"
    os.environ["OPENAI_API_KEY"] = "xyz"
    
    llm = OpenAI(temperature=0)
    jira = JiraAPIWrapper()
    toolkit = JiraToolkit.from_jira_api_wrapper(jira)
    agent = initialize_agent(
        toolkit.get_tools(), llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True
    )
    

    You’ll be able to instruct the agent to create a brand new challenge in a particular undertaking with a abstract and outline:

    agent.run("make a brand new challenge in undertaking PW to remind me to make extra fried rice")
    

    The agent will execute the required actions to create the difficulty and supply a response, equivalent to “A brand new challenge has been created in undertaking PW with the abstract ‘Make extra fried rice’ and outline ‘Reminder to make extra fried rice’.”

    This lets you work together along with your Jira occasion utilizing pure language directions and the Jira toolkit.


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    Module IV : Chains

    LangChain is a device designed for using Giant Language Fashions (LLMs) in complicated functions. It gives frameworks for creating chains of elements, together with LLMs and different kinds of elements. Two main frameworks

    • The LangChain Expression Language (LCEL)
    • Legacy Chain interface

    The LangChain Expression Language (LCEL) is a syntax that permits for intuitive composition of chains. It helps superior options like streaming, asynchronous calls, batching, parallelization, retries, fallbacks, and tracing. For instance, you may compose a immediate, mannequin, and output parser in LCEL as proven within the following code:

    from langchain.prompts import ChatPromptTemplate
    from langchain.schema import StrOutputParser
    
    mannequin = ChatOpenAI(mannequin="gpt-3.5-turbo", temperature=0)
    immediate = ChatPromptTemplate.from_messages([
        ("system", "You're a very knowledgeable historian who provides accurate and eloquent answers to historical questions."),
        ("human", "{question}")
    ])
    runnable = immediate | mannequin | StrOutputParser()
    
    for chunk in runnable.stream({"query": "What are the seven wonders of the world"}):
        print(chunk, finish="", flush=True)

    Alternatively, the LLMChain is an choice just like LCEL for composing elements. The LLMChain instance is as follows:

    from langchain.chains import LLMChain
    
    chain = LLMChain(llm=mannequin, immediate=immediate, output_parser=StrOutputParser())
    chain.run(query="What are the seven wonders of the world")
    

    Chains in LangChain can be stateful by incorporating a Reminiscence object. This enables for information persistence throughout calls, as proven on this instance:

    from langchain.chains import ConversationChain
    from langchain.reminiscence import ConversationBufferMemory
    
    dialog = ConversationChain(llm=chat, reminiscence=ConversationBufferMemory())
    dialog.run("Reply briefly. What are the primary 3 colours of a rainbow?")
    dialog.run("And the following 4?")
    

    LangChain additionally helps integration with OpenAI’s function-calling APIs, which is helpful for acquiring structured outputs and executing features inside a series. For getting structured outputs, you may specify them utilizing Pydantic courses or JsonSchema, as illustrated beneath:

    from langchain.pydantic_v1 import BaseModel, Subject
    from langchain.chains.openai_functions import create_structured_output_runnable
    from langchain.chat_models import ChatOpenAI
    from langchain.prompts import ChatPromptTemplate
    
    class Particular person(BaseModel):
        identify: str = Subject(..., description="The particular person's identify")
        age: int = Subject(..., description="The particular person's age")
        fav_food: Elective[str] = Subject(None, description="The particular person's favourite meals")
    
    llm = ChatOpenAI(mannequin="gpt-4", temperature=0)
    immediate = ChatPromptTemplate.from_messages([
        # Prompt messages here
    ])
    
    runnable = create_structured_output_runnable(Particular person, llm, immediate)
    runnable.invoke({"enter": "Sally is 13"})
    

    For structured outputs, a legacy method utilizing LLMChain can be accessible:

    from langchain.chains.openai_functions import create_structured_output_chain
    
    class Particular person(BaseModel):
        identify: str = Subject(..., description="The particular person's identify")
        age: int = Subject(..., description="The particular person's age")
    
    chain = create_structured_output_chain(Particular person, llm, immediate, verbose=True)
    chain.run("Sally is 13")

    LangChain leverages OpenAI features to create numerous particular chains for various functions. These embrace chains for extraction, tagging, OpenAPI, and QA with citations.

    Within the context of extraction, the method is just like the structured output chain however focuses on info or entity extraction. For tagging, the concept is to label a doc with courses equivalent to sentiment, language, type, lined subjects, or political tendency.

    An instance of how tagging works in LangChain may be demonstrated with a Python code. The method begins with putting in the required packages and establishing the setting:

    pip set up langchain openai
    # Set env var OPENAI_API_KEY or load from a .env file:
    # import dotenv
    # dotenv.load_dotenv()
    
    from langchain.chat_models import ChatOpenAI
    from langchain.prompts import ChatPromptTemplate
    from langchain.chains import create_tagging_chain, create_tagging_chain_pydantic
    

    The schema for tagging is outlined, specifying the properties and their anticipated varieties:

    schema = {
        "properties": {
            "sentiment": {"sort": "string"},
            "aggressiveness": {"sort": "integer"},
            "language": {"sort": "string"},
        }
    }
    
    llm = ChatOpenAI(temperature=0, mannequin="gpt-3.5-turbo-0613")
    chain = create_tagging_chain(schema, llm)
    

    Examples of operating the tagging chain with totally different inputs present the mannequin’s capability to interpret sentiments, languages, and aggressiveness:

    inp = "Estoy increiblemente contento de haberte conocido! Creo que seremos muy buenos amigos!"
    chain.run(inp)
    # {'sentiment': 'constructive', 'language': 'Spanish'}
    
    inp = "Estoy muy enojado con vos! Te voy a dar tu merecido!"
    chain.run(inp)
    # {'sentiment': 'enojado', 'aggressiveness': 1, 'language': 'es'}
    

    For finer management, the schema may be outlined extra particularly, together with doable values, descriptions, and required properties. An instance of this enhanced management is proven beneath:

    schema = {
        "properties": {
            # Schema definitions right here
        },
        "required": ["language", "sentiment", "aggressiveness"],
    }
    
    chain = create_tagging_chain(schema, llm)
    

    Pydantic schemas can be used for outlining tagging standards, offering a Pythonic solution to specify required properties and kinds:

    from enum import Enum
    from pydantic import BaseModel, Subject
    
    class Tags(BaseModel):
        # Class fields right here
    
    chain = create_tagging_chain_pydantic(Tags, llm)
    

    Moreover, LangChain’s metadata tagger doc transformer can be utilized to extract metadata from LangChain Paperwork, providing comparable performance to the tagging chain however utilized to a LangChain Doc.

    Citing retrieval sources is one other function of LangChain, utilizing OpenAI features to extract citations from textual content. That is demonstrated within the following code:

    from langchain.chains import create_citation_fuzzy_match_chain
    from langchain.chat_models import ChatOpenAI
    
    llm = ChatOpenAI(temperature=0, mannequin="gpt-3.5-turbo-0613")
    chain = create_citation_fuzzy_match_chain(llm)
    # Additional code for operating the chain and displaying outcomes
    

    In LangChain, chaining in Giant Language Mannequin (LLM) functions sometimes entails combining a immediate template with an LLM and optionally an output parser. The advisable means to do that is thru the LangChain Expression Language (LCEL), though the legacy LLMChain method can be supported.

    Utilizing LCEL, the BasePromptTemplate, BaseLanguageModel, and BaseOutputParser all implement the Runnable interface and may be simply piped into each other. This is an instance demonstrating this:

    from langchain.prompts import PromptTemplate
    from langchain.chat_models import ChatOpenAI
    from langchain.schema import StrOutputParser
    
    immediate = PromptTemplate.from_template(
        "What is an effective identify for a corporation that makes {product}?"
    )
    runnable = immediate | ChatOpenAI() | StrOutputParser()
    runnable.invoke({"product": "colourful socks"})
    # Output: 'VibrantSocks'
    

    Routing in LangChain permits for creating non-deterministic chains the place the output of a earlier step determines the following step. This helps in structuring and sustaining consistency in interactions with LLMs. As an example, when you have two templates optimized for various kinds of questions, you may select the template based mostly on person enter.

    This is how one can obtain this utilizing LCEL with a RunnableBranch, which is initialized with an inventory of (situation, runnable) pairs and a default runnable:

    from langchain.chat_models import ChatOpenAI
    from langchain.schema.output_parser import StrOutputParser
    from langchain.schema.runnable import RunnableBranch
    # Code for outlining physics_prompt and math_prompt
    
    general_prompt = PromptTemplate.from_template(
        "You're a useful assistant. Reply the query as precisely as you may.nn{enter}"
    )
    prompt_branch = RunnableBranch(
        (lambda x: x["topic"] == "math", math_prompt),
        (lambda x: x["topic"] == "physics", physics_prompt),
        general_prompt,
    )
    
    # Extra code for establishing the classifier and last chain
    

    The ultimate chain is then constructed utilizing numerous elements, equivalent to a subject classifier, immediate department, and an output parser, to find out the circulation based mostly on the subject of the enter:

    from operator import itemgetter
    from langchain.schema.output_parser import StrOutputParser
    from langchain.schema.runnable import RunnablePassthrough
    
    final_chain = (
        RunnablePassthrough.assign(matter=itemgetter("enter") | classifier_chain)
        | prompt_branch
        | ChatOpenAI()
        | StrOutputParser()
    )
    
    final_chain.invoke(
        {
            "enter": "What's the first prime quantity larger than 40 such that one plus the prime quantity is divisible by 3?"
        }
    )
    # Output: Detailed reply to the mathematics query
    

    This method exemplifies the pliability and energy of LangChain in dealing with complicated queries and routing them appropriately based mostly on the enter.

    Within the realm of language fashions, a typical follow is to observe up an preliminary name with a sequence of subsequent calls, utilizing the output of 1 name as enter for the following. This sequential method is particularly helpful whenever you need to construct on the data generated in earlier interactions. Whereas the LangChain Expression Language (LCEL) is the advisable technique for creating these sequences, the SequentialChain technique continues to be documented for its backward compatibility.

    For instance this, let’s contemplate a state of affairs the place we first generate a play synopsis after which a evaluation based mostly on that synopsis. Utilizing Python’s langchain.prompts, we create two PromptTemplate cases: one for the synopsis and one other for the evaluation. This is the code to arrange these templates:

    from langchain.prompts import PromptTemplate
    
    synopsis_prompt = PromptTemplate.from_template(
        "You're a playwright. Given the title of play, it's your job to write down a synopsis for that title.nnTitle: {title}nPlaywright: This can be a synopsis for the above play:"
    )
    
    review_prompt = PromptTemplate.from_template(
        "You're a play critic from the New York Instances. Given the synopsis of play, it's your job to write down a evaluation for that play.nnPlay Synopsis:n{synopsis}nReview from a New York Instances play critic of the above play:"
    )
    

    Within the LCEL method, we chain these prompts with ChatOpenAI and StrOutputParser to create a sequence that first generates a synopsis after which a evaluation. The code snippet is as follows:

    from langchain.chat_models import ChatOpenAI
    from langchain.schema import StrOutputParser
    
    llm = ChatOpenAI()
    chain = (
         llm 
        | review_prompt
        | llm
        | StrOutputParser()
    )
    chain.invoke({"title": "Tragedy at sundown on the seashore"})
    

    If we want each the synopsis and the evaluation, we are able to use RunnablePassthrough to create a separate chain for every after which mix them:

    from langchain.schema.runnable import RunnablePassthrough
    
    synopsis_chain = synopsis_prompt | llm | StrOutputParser()
    review_chain = review_prompt | llm | StrOutputParser()
    chain = {"synopsis": synopsis_chain} | RunnablePassthrough.assign(evaluation=review_chain)
    chain.invoke({"title": "Tragedy at sundown on the seashore"})
    

    For eventualities involving extra complicated sequences, the SequentialChain technique comes into play. This enables for a number of inputs and outputs. Contemplate a case the place we want a synopsis based mostly on a play’s title and period. This is how we would set it up:

    from langchain.llms import OpenAI
    from langchain.chains import LLMChain, SequentialChain
    from langchain.prompts import PromptTemplate
    
    llm = OpenAI(temperature=0.7)
    
    synopsis_template = "You're a playwright. Given the title of play and the period it's set in, it's your job to write down a synopsis for that title.nnTitle: {title}nEra: {period}nPlaywright: This can be a synopsis for the above play:"
    synopsis_prompt_template = PromptTemplate(input_variables=["title", "era"], template=synopsis_template)
    synopsis_chain = LLMChain(llm=llm, immediate=synopsis_prompt_template, output_key="synopsis")
    
    review_template = "You're a play critic from the New York Instances. Given the synopsis of play, it's your job to write down a evaluation for that play.nnPlay Synopsis:n{synopsis}nReview from a New York Instances play critic of the above play:"
    prompt_template = PromptTemplate(input_variables=["synopsis"], template=review_template)
    review_chain = LLMChain(llm=llm, immediate=prompt_template, output_key="evaluation")
    
    overall_chain = SequentialChain(
        chains=[synopsis_chain, review_chain],
        input_variables=["era", "title"],
        output_variables=["synopsis", "review"],
        verbose=True,
    )
    
    overall_chain({"title": "Tragedy at sundown on the seashore", "period": "Victorian England"})
    

    In eventualities the place you need to preserve context all through a series or for a later a part of the chain, SimpleMemory can be utilized. That is significantly helpful for managing complicated enter/output relationships. As an example, in a state of affairs the place we need to generate social media posts based mostly on a play’s title, period, synopsis, and evaluation, SimpleMemory may help handle these variables:

    from langchain.reminiscence import SimpleMemory
    from langchain.chains import SequentialChain
    
    template = "You're a social media supervisor for a theater firm. Given the title of play, the period it's set in, the date, time and placement, the synopsis of the play, and the evaluation of the play,
    
     it's your job to write down a social media put up for that play.nnHere is a few context concerning the time and placement of the play:nDate and Time: {time}nLocation: {location}nnPlay Synopsis:n{synopsis}nReview from a New York Instances play critic of the above play:n{evaluation}nnSocial Media Put up:"
    prompt_template = PromptTemplate(input_variables=["synopsis", "review", "time", "location"], template=template)
    social_chain = LLMChain(llm=llm, immediate=prompt_template, output_key="social_post_text")
    
    overall_chain = SequentialChain(
        reminiscence=SimpleMemory(recollections={"time": "December twenty fifth, 8pm PST", "location": "Theater within the Park"}),
        chains=[synopsis_chain, review_chain, social_chain],
        input_variables=["era", "title"],
        output_variables=["social_post_text"],
        verbose=True,
    )
    
    overall_chain({"title": "Tragedy at sundown on the seashore", "period": "Victorian England"})
    

    Along with sequential chains, there are specialised chains for working with paperwork. Every of those chains serves a special function, from combining paperwork to refining solutions based mostly on iterative doc evaluation, to mapping and lowering doc content material for summarization or re-ranking based mostly on scored responses. These chains may be recreated with LCEL for extra flexibility and customization.

    • StuffDocumentsChain combines an inventory of paperwork right into a single immediate handed to an LLM.
    • RefineDocumentsChain updates its reply iteratively for every doc, appropriate for duties the place paperwork exceed the mannequin’s context capability.
    • MapReduceDocumentsChain applies a series to every doc individually after which combines the outcomes.
    • MapRerankDocumentsChain scores every document-based response and selects the highest-scoring one.

    This is an instance of the way you would possibly arrange a MapReduceDocumentsChain utilizing LCEL:

    from functools import partial
    from langchain.chains.combine_documents import collapse_docs, split_list_of_docs
    from langchain.schema import Doc, StrOutputParser
    from langchain.schema.prompt_template import format_document
    from langchain.schema.runnable import RunnableParallel, RunnablePassthrough
    
    llm = ChatAnthropic()
    document_prompt = PromptTemplate.from_template("{page_content}")
    partial_format_document = partial(format_document, immediate=document_prompt)
    
    map_chain = (
        {"context": partial_format_document}
        | PromptTemplate.from_template("Summarize this content material:nn{context}")
        | llm
        | StrOutputParser()
    )
    
    map_as_doc_chain = (
        RunnableParallel({"doc": RunnablePassthrough(), "content material": map_chain})
        | (lambda x: Doc(page_content=x["content"], metadata=x["doc"].metadata))
    ).with_config(run_name="Summarize (return doc)")
    
    def format_docs(docs):
        return "nn".be part of(partial_format_document(doc) for doc in docs)
    
    collapse_chain = (
        {"context": format_docs}
        | PromptTemplate.from_template("Collapse this content material:nn{context}")
        | llm
        | StrOutputParser()
    )
    
    reduce_chain = (
        {"context": format_docs}
        | PromptTemplate.from_template("Mix these summaries:nn{context}")
        | llm
        | StrOutputParser()
    ).with_config(run_name="Scale back")
    
    map_reduce = (map_as_doc_chain.map() | collapse | reduce_chain).with_config(run_name="Map cut back")
    

    This configuration permits for an in depth and complete evaluation of doc content material, leveraging the strengths of LCEL and the underlying language mannequin.


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    Module V : Reminiscence

    In LangChain, reminiscence is a basic facet of conversational interfaces, permitting techniques to reference previous interactions. That is achieved by way of storing and querying info, with two main actions: studying and writing. The reminiscence system interacts with a series twice throughout a run, augmenting person inputs and storing the inputs and outputs for future reference.

    Constructing Reminiscence right into a System

    1. Storing Chat Messages: The LangChain reminiscence module integrates numerous strategies to retailer chat messages, starting from in-memory lists to databases. This ensures that every one chat interactions are recorded for future reference.
    2. Querying Chat Messages: Past storing chat messages, LangChain employs information constructions and algorithms to create a helpful view of those messages. Easy reminiscence techniques would possibly return current messages, whereas extra superior techniques may summarize previous interactions or give attention to entities talked about within the present interplay.

    To display using reminiscence in LangChain, contemplate the ConversationBufferMemory class, a easy reminiscence kind that shops chat messages in a buffer. This is an instance:

    from langchain.reminiscence import ConversationBufferMemory
    
    reminiscence = ConversationBufferMemory()
    reminiscence.chat_memory.add_user_message("Howdy!")
    reminiscence.chat_memory.add_ai_message("How can I help you?")
    

    When integrating reminiscence into a series, it is essential to know the variables returned from reminiscence and the way they’re used within the chain. As an example, the load_memory_variables technique helps align the variables learn from reminiscence with the chain’s expectations.

    Finish-to-Finish Instance with LangChain

    Think about using ConversationBufferMemory in an LLMChain. The chain, mixed with an acceptable immediate template and the reminiscence, gives a seamless conversational expertise. This is a simplified instance:

    from langchain.llms import OpenAI
    from langchain.prompts import PromptTemplate
    from langchain.chains import LLMChain
    from langchain.reminiscence import ConversationBufferMemory
    
    llm = OpenAI(temperature=0)
    template = "Your dialog template right here..."
    immediate = PromptTemplate.from_template(template)
    reminiscence = ConversationBufferMemory(memory_key="chat_history")
    dialog = LLMChain(llm=llm, immediate=immediate, reminiscence=reminiscence)
    
    response = dialog({"query": "What is the climate like?"})
    

    This instance illustrates how LangChain’s reminiscence system integrates with its chains to supply a coherent and contextually conscious conversational expertise.

    Reminiscence Varieties in Langchain

    Langchain presents numerous reminiscence varieties that may be utilized to boost interactions with the AI fashions. Every reminiscence sort has its personal parameters and return varieties, making them appropriate for various eventualities. Let’s discover among the reminiscence varieties accessible in Langchain together with code examples.

    1. Dialog Buffer Reminiscence

    This reminiscence sort means that you can retailer and extract messages from conversations. You’ll be able to extract the historical past as a string or as an inventory of messages.

    from langchain.reminiscence import ConversationBufferMemory
    
    reminiscence = ConversationBufferMemory()
    reminiscence.save_context({"enter": "hello"}, {"output": "whats up"})
    reminiscence.load_memory_variables({})
    
    # Extract historical past as a string
    {'historical past': 'Human: hinAI: whats up'}
    
    # Extract historical past as an inventory of messages
    {'historical past': [HumanMessage(content="hi", additional_kwargs={}),
      AIMessage(content="whats up", additional_kwargs={})]}
    

    You may also use Dialog Buffer Reminiscence in a series for chat-like interactions.

    2. Dialog Buffer Window Reminiscence

    This reminiscence sort retains an inventory of current interactions and makes use of the final Ok interactions, stopping the buffer from getting too massive.

    from langchain.reminiscence import ConversationBufferWindowMemory
    
    reminiscence = ConversationBufferWindowMemory(ok=1)
    reminiscence.save_context({"enter": "hello"}, {"output": "whats up"})
    reminiscence.save_context({"enter": "not a lot you"}, {"output": "not a lot"})
    reminiscence.load_memory_variables({})
    
    {'historical past': 'Human: not a lot younAI: not a lot'}
    

    Like Dialog Buffer Reminiscence, you may as well use this reminiscence sort in a series for chat-like interactions.

    3. Dialog Entity Reminiscence

    This reminiscence sort remembers information about particular entities in a dialog and extracts info utilizing an LLM.

    from langchain.reminiscence import ConversationEntityMemory
    from langchain.llms import OpenAI
    
    llm = OpenAI(temperature=0)
    reminiscence = ConversationEntityMemory(llm=llm)
    _input = {"enter": "Deven & Sam are engaged on a hackathon undertaking"}
    reminiscence.load_memory_variables(_input)
    reminiscence.save_context(
        _input,
        {"output": " That feels like a fantastic undertaking! What sort of undertaking are they engaged on?"}
    )
    reminiscence.load_memory_variables({"enter": 'who's Sam'})
    
    {'historical past': 'Human: Deven & Sam are engaged on a hackathon projectnAI:  That feels like a fantastic undertaking! What sort of undertaking are they engaged on?',
     'entities': {'Sam': 'Sam is engaged on a hackathon undertaking with Deven.'}}
    

    4. Dialog Data Graph Reminiscence

    This reminiscence sort makes use of a information graph to recreate reminiscence. You’ll be able to extract present entities and information triplets from messages.

    from langchain.reminiscence import ConversationKGMemory
    from langchain.llms import OpenAI
    
    llm = OpenAI(temperature=0)
    reminiscence = ConversationKGMemory(llm=llm)
    reminiscence.save_context({"enter": "say hello to sam"}, {"output": "who's sam"})
    reminiscence.save_context({"enter": "sam is a pal"}, {"output": "okay"})
    reminiscence.load_memory_variables({"enter": "who's sam"})
    
    {'historical past': 'On Sam: Sam is pal.'}
    

    You may also use this reminiscence sort in a series for conversation-based information retrieval.

    5. Dialog Abstract Reminiscence

    This reminiscence sort creates a abstract of the dialog over time, helpful for condensing info from longer conversations.

    from langchain.reminiscence import ConversationSummaryMemory
    from langchain.llms import OpenAI
    
    llm = OpenAI(temperature=0)
    reminiscence = ConversationSummaryMemory(llm=llm)
    reminiscence.save_context({"enter": "hello"}, {"output": "whats up"})
    reminiscence.load_memory_variables({})
    
    {'historical past': 'nThe human greets the AI, to which the AI responds.'}
    

    6. Dialog Abstract Buffer Reminiscence

    This reminiscence sort combines the dialog abstract and buffer, sustaining a stability between current interactions and a abstract. It makes use of token size to find out when to flush interactions.

    from langchain.reminiscence import ConversationSummaryBufferMemory
    from langchain.llms import OpenAI
    
    llm = OpenAI()
    reminiscence = ConversationSummaryBufferMemory(llm=llm, max_token_limit=10)
    reminiscence.save_context({"enter": "hello"}, {"output": "whats up"})
    reminiscence.save_context({"enter": "not a lot you"}, {"output": "not a lot"})
    reminiscence.load_memory_variables({})
    
    {'historical past': 'System: nThe human says "hello", and the AI responds with "whats up".nHuman: not a lot younAI: not a lot'}
    

    You need to use these reminiscence varieties to boost your interactions with AI fashions in Langchain. Every reminiscence sort serves a particular function and may be chosen based mostly in your necessities.

    7. Dialog Token Buffer Reminiscence

    ConversationTokenBufferMemory is one other reminiscence sort that retains a buffer of current interactions in reminiscence. Not like the earlier reminiscence varieties that target the variety of interactions, this one makes use of token size to find out when to flush interactions.

    Utilizing reminiscence with LLM:

    from langchain.reminiscence import ConversationTokenBufferMemory
    from langchain.llms import OpenAI
    
    llm = OpenAI()
    
    reminiscence = ConversationTokenBufferMemory(llm=llm, max_token_limit=10)
    reminiscence.save_context({"enter": "hello"}, {"output": "whats up"})
    reminiscence.save_context({"enter": "not a lot you"}, {"output": "not a lot"})
    
    reminiscence.load_memory_variables({})
    
    {'historical past': 'Human: not a lot younAI: not a lot'}
    

    On this instance, the reminiscence is about to restrict interactions based mostly on token size moderately than the variety of interactions.

    You may also get the historical past as an inventory of messages when utilizing this reminiscence sort.

    reminiscence = ConversationTokenBufferMemory(
        llm=llm, max_token_limit=10, return_messages=True
    )
    reminiscence.save_context({"enter": "hello"}, {"output": "whats up"})
    reminiscence.save_context({"enter": "not a lot you"}, {"output": "not a lot"})
    

    Utilizing in a series:

    You need to use ConversationTokenBufferMemory in a series to boost interactions with the AI mannequin.

    from langchain.chains import ConversationChain
    
    conversation_with_summary = ConversationChain(
        llm=llm,
        # We set a really low max_token_limit for the needs of testing.
        reminiscence=ConversationTokenBufferMemory(llm=OpenAI(), max_token_limit=60),
        verbose=True,
    )
    conversation_with_summary.predict(enter="Hello, what's up?")
    

    On this instance, ConversationTokenBufferMemory is utilized in a ConversationChain to handle the dialog and restrict interactions based mostly on token size.

    8. VectorStoreRetrieverMemory

    VectorStoreRetrieverMemory shops recollections in a vector retailer and queries the top-Ok most “salient” paperwork each time it’s known as. This reminiscence sort would not explicitly monitor the order of interactions however makes use of vector retrieval to fetch related recollections.

    from datetime import datetime
    from langchain.embeddings.openai import OpenAIEmbeddings
    from langchain.llms import OpenAI
    from langchain.reminiscence import VectorStoreRetrieverMemory
    from langchain.chains import ConversationChain
    from langchain.prompts import PromptTemplate
    
    # Initialize your vector retailer (specifics rely upon the chosen vector retailer)
    import faiss
    from langchain.docstore import InMemoryDocstore
    from langchain.vectorstores import FAISS
    
    embedding_size = 1536  # Dimensions of the OpenAIEmbeddings
    index = faiss.IndexFlatL2(embedding_size)
    embedding_fn = OpenAIEmbeddings().embed_query
    vectorstore = FAISS(embedding_fn, index, InMemoryDocstore({}), {})
    
    # Create your VectorStoreRetrieverMemory
    retriever = vectorstore.as_retriever(search_kwargs=dict(ok=1))
    reminiscence = VectorStoreRetrieverMemory(retriever=retriever)
    
    # Save context and related info to the reminiscence
    reminiscence.save_context({"enter": "My favourite meals is pizza"}, {"output": "that is good to know"})
    reminiscence.save_context({"enter": "My favourite sport is soccer"}, {"output": "..."})
    reminiscence.save_context({"enter": "I do not just like the Celtics"}, {"output": "okay"})
    
    # Retrieve related info from reminiscence based mostly on a question
    print(reminiscence.load_memory_variables({"immediate": "what sport ought to i watch?"})["history"])
    

    On this instance, VectorStoreRetrieverMemory is used to retailer and retrieve related info from a dialog based mostly on vector retrieval.

    You may also use VectorStoreRetrieverMemory in a series for conversation-based information retrieval, as proven within the earlier examples.

    These totally different reminiscence varieties in Langchain present numerous methods to handle and retrieve info from conversations, enhancing the capabilities of AI fashions in understanding and responding to person queries and context. Every reminiscence sort may be chosen based mostly on the particular necessities of your utility.


    Now we’ll discover ways to use reminiscence with an LLMChain. Reminiscence in an LLMChain permits the mannequin to recollect earlier interactions and context to supply extra coherent and context-aware responses.

    To arrange reminiscence in an LLMChain, it’s worthwhile to create a reminiscence class, equivalent to ConversationBufferMemory. This is how one can set it up:

    from langchain.chains import LLMChain
    from langchain.llms import OpenAI
    from langchain.reminiscence import ConversationBufferMemory
    from langchain.prompts import PromptTemplate
    
    template = """You're a chatbot having a dialog with a human.
    
    {chat_history}
    Human: {human_input}
    Chatbot:"""
    
    immediate = PromptTemplate(
        input_variables=["chat_history", "human_input"], template=template
    )
    reminiscence = ConversationBufferMemory(memory_key="chat_history")
    
    llm = OpenAI()
    llm_chain = LLMChain(
        llm=llm,
        immediate=immediate,
        verbose=True,
        reminiscence=reminiscence,
    )
    
    llm_chain.predict(human_input="Hello there my pal")
    

    On this instance, the ConversationBufferMemory is used to retailer the dialog historical past. The memory_key parameter specifies the important thing used to retailer the dialog historical past.

    If you’re utilizing a chat mannequin as a substitute of a completion-style mannequin, you may construction your prompts in another way to raised make the most of the reminiscence. This is an instance of how one can arrange a chat model-based LLMChain with reminiscence:

    from langchain.chat_models import ChatOpenAI
    from langchain.schema import SystemMessage
    from langchain.prompts import (
        ChatPromptTemplate,
        HumanMessagePromptTemplate,
        MessagesPlaceholder,
    )
    
    # Create a ChatPromptTemplate
    immediate = ChatPromptTemplate.from_messages(
        [
            SystemMessage(
                content="You are a chatbot having a conversation with a human."
            ),  # The persistent system prompt
            MessagesPlaceholder(
                variable_name="chat_history"
            ),  # Where the memory will be stored.
            HumanMessagePromptTemplate.from_template(
                "{human_input}"
            ),  # Where the human input will be injected
        ]
    )
    
    reminiscence = ConversationBufferMemory(memory_key="chat_history", return_messages=True)
    
    llm = ChatOpenAI()
    
    chat_llm_chain = LLMChain(
        llm=llm,
        immediate=immediate,
        verbose=True,
        reminiscence=reminiscence,
    )
    
    chat_llm_chain.predict(human_input="Hello there my pal")
    

    On this instance, the ChatPromptTemplate is used to construction the immediate, and the ConversationBufferMemory is used to retailer and retrieve the dialog historical past. This method is especially helpful for chat-style conversations the place context and historical past play an important function.

    Reminiscence can be added to a series with a number of inputs, equivalent to a query/answering chain. This is an instance of how one can arrange reminiscence in a query/answering chain:

    from langchain.embeddings.openai import OpenAIEmbeddings
    from langchain.embeddings.cohere import CohereEmbeddings
    from langchain.text_splitter import CharacterTextSplitter
    from langchain.vectorstores.elastic_vector_search import ElasticVectorSearch
    from langchain.vectorstores import Chroma
    from langchain.docstore.doc import Doc
    from langchain.chains.question_answering import load_qa_chain
    from langchain.llms import OpenAI
    from langchain.prompts import PromptTemplate
    from langchain.reminiscence import ConversationBufferMemory
    
    # Break up an extended doc into smaller chunks
    with open("../../state_of_the_union.txt") as f:
        state_of_the_union = f.learn()
    text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
    texts = text_splitter.split_text(state_of_the_union)
    
    # Create an ElasticVectorSearch occasion to index and search the doc chunks
    embeddings = OpenAIEmbeddings()
    docsearch = Chroma.from_texts(
        texts, embeddings, metadatas=[{"source": i} for i in range(len(texts))]
    )
    
    # Carry out a query concerning the doc
    question = "What did the president say about Justice Breyer"
    docs = docsearch.similarity_search(question)
    
    # Arrange a immediate for the question-answering chain with reminiscence
    template = """You're a chatbot having a dialog with a human.
    
    Given the next extracted elements of an extended doc and a query, create a last reply.
    
    {context}
    
    {chat_history}
    Human: {human_input}
    Chatbot:"""
    
    immediate = PromptTemplate(
        input_variables=["chat_history", "human_input", "context"], template=template
    )
    reminiscence = ConversationBufferMemory(memory_key="chat_history", input_key="human_input")
    chain = load_qa_chain(
        OpenAI(temperature=0), chain_type="stuff", reminiscence=reminiscence, immediate=immediate
    )
    
    # Ask the query and retrieve the reply
    question = "What did the president say about Justice Breyer"
    end result = chain({"input_documents": docs, "human_input": question}, return_only_outputs=True)
    
    print(end result)
    print(chain.reminiscence.buffer)
    

    On this instance, a query is answered utilizing a doc cut up into smaller chunks. The ConversationBufferMemory is used to retailer and retrieve the dialog historical past, permitting the mannequin to supply context-aware solutions.

    Including reminiscence to an agent permits it to recollect and use earlier interactions to reply questions and supply context-aware responses. This is how one can arrange reminiscence in an agent:

    from langchain.brokers import ZeroShotAgent, Instrument, AgentExecutor
    from langchain.reminiscence import ConversationBufferMemory
    from langchain.llms import OpenAI
    from langchain.chains import LLMChain
    from langchain.utilities import GoogleSearchAPIWrapper
    
    # Create a device for looking out
    search = GoogleSearchAPIWrapper()
    instruments = [
        Tool(
            name="Search",
            func=search.run,
            description="useful for when you need to answer questions about current events",
        )
    ]
    
    # Create a immediate with reminiscence
    prefix = """Have a dialog with a human, answering the next questions as greatest you may. You've got entry to the next instruments:"""
    suffix = """Start!"
    
    {chat_history}
    Query: {enter}
    {agent_scratchpad}"""
    
    immediate = ZeroShotAgent.create_prompt(
        instruments,
        prefix=prefix,
        suffix=suffix,
        input_variables=["input", "chat_history", "agent_scratchpad"],
    )
    reminiscence = ConversationBufferMemory(memory_key="chat_history")
    
    # Create an LLMChain with reminiscence
    llm_chain = LLMChain(llm=OpenAI(temperature=0), immediate=immediate)
    agent = ZeroShotAgent(llm_chain=llm_chain, instruments=instruments, verbose=True)
    agent_chain = AgentExecutor.from_agent_and_tools(
        agent=agent, instruments=instruments, verbose=True, reminiscence=reminiscence
    )
    
    # Ask a query and retrieve the reply
    response = agent_chain.run(enter="How many individuals reside
    
     in Canada?")
    print(response)
    
    # Ask a follow-up query
    response = agent_chain.run(enter="What's their nationwide anthem known as?")
    print(response)
    

    On this instance, reminiscence is added to an agent, permitting it to recollect the earlier dialog historical past and supply context-aware solutions. This allows the agent to reply follow-up questions precisely based mostly on the data saved in reminiscence.

    LangChain Expression Language

    On this planet of pure language processing and machine studying, composing complicated chains of operations is usually a daunting process. Thankfully, LangChain Expression Language (LCEL) involves the rescue, offering a declarative and environment friendly solution to construct and deploy refined language processing pipelines. LCEL is designed to simplify the method of composing chains, making it doable to go from prototyping to manufacturing with ease. On this weblog, we’ll discover what LCEL is and why you would possibly need to use it, together with sensible code examples as an instance its capabilities.

    LCEL, or LangChain Expression Language, is a strong device for composing language processing chains. It was purpose-built to assist the transition from prototyping to manufacturing seamlessly, with out requiring in depth code adjustments. Whether or not you are constructing a easy “immediate + LLM” chain or a fancy pipeline with a whole bunch of steps, LCEL has you lined.

    Listed here are some causes to make use of LCEL in your language processing initiatives:

    1. Quick Token Streaming: LCEL delivers tokens from a Language Mannequin to an output parser in real-time, bettering responsiveness and effectivity.
    2. Versatile APIs: LCEL helps each synchronous and asynchronous APIs for prototyping and manufacturing use, dealing with a number of requests effectively.
    3. Automated Parallelization: LCEL optimizes parallel execution when doable, lowering latency in each sync and async interfaces.
    4. Dependable Configurations: Configure retries and fallbacks for enhanced chain reliability at scale, with streaming assist in improvement.
    5. Stream Intermediate Outcomes: Entry intermediate outcomes throughout processing for person updates or debugging functions.
    6. Schema Era: LCEL generates Pydantic and JSONSchema schemas for enter and output validation.
    7. Complete Tracing: LangSmith robotically traces all steps in complicated chains for observability and debugging.
    8. Simple Deployment: Deploy LCEL-created chains effortlessly utilizing LangServe.

    Now, let’s dive into sensible code examples that display the facility of LCEL. We’ll discover widespread duties and eventualities the place LCEL shines.

    Immediate + LLM

    Essentially the most basic composition entails combining a immediate and a language mannequin to create a series that takes person enter, provides it to a immediate, passes it to a mannequin, and returns the uncooked mannequin output. This is an instance:

    from langchain.prompts import ChatPromptTemplate
    from langchain.chat_models import ChatOpenAI
    
    immediate = ChatPromptTemplate.from_template("inform me a joke about {foo}")
    mannequin = ChatOpenAI()
    chain = immediate | mannequin
    
    end result = chain.invoke({"foo": "bears"})
    print(end result)
    

    On this instance, the chain generates a joke about bears.

    You’ll be able to connect cease sequences to your chain to regulate the way it processes textual content. For instance:

    chain = immediate | mannequin.bind(cease=["n"])
    end result = chain.invoke({"foo": "bears"})
    print(end result)
    

    This configuration stops textual content technology when a newline character is encountered.

    LCEL helps attaching operate name info to your chain. This is an instance:

    features = [
        {
            "name": "joke",
            "description": "A joke",
            "parameters": {
                "type": "object",
                "properties": {
                    "setup": {"type": "string", "description": "The setup for the joke"},
                    "punchline": {
                        "type": "string",
                        "description": "The punchline for the joke",
                    },
                },
                "required": ["setup", "punchline"],
            },
        }
    ]
    chain = immediate | mannequin.bind(function_call={"identify": "joke"}, features=features)
    end result = chain.invoke({"foo": "bears"}, config={})
    print(end result)
    

    This instance attaches operate name info to generate a joke.

    Immediate + LLM + OutputParser

    You’ll be able to add an output parser to rework the uncooked mannequin output right into a extra workable format. This is how you are able to do it:

    from langchain.schema.output_parser import StrOutputParser
    
    chain = immediate | mannequin | StrOutputParser()
    end result = chain.invoke({"foo": "bears"})
    print(end result)
    

    The output is now in a string format, which is extra handy for downstream duties.

    When specifying a operate to return, you may parse it straight utilizing LCEL. For instance:

    from langchain.output_parsers.openai_functions import JsonOutputFunctionsParser
    
    chain = (
        immediate
        | mannequin.bind(function_call={"identify": "joke"}, features=features)
        | JsonOutputFunctionsParser()
    )
    end result = chain.invoke({"foo": "bears"})
    print(end result)
    

    This instance parses the output of the “joke” operate straight.

    These are just some examples of how LCEL simplifies complicated language processing duties. Whether or not you are constructing chatbots, producing content material, or performing complicated textual content transformations, LCEL can streamline your workflow and make your code extra maintainable.

    RAG (Retrieval-augmented Era)

    LCEL can be utilized to create retrieval-augmented technology chains, which mix retrieval and language technology steps. This is an instance:

    from operator import itemgetter
    
    from langchain.prompts import ChatPromptTemplate
    from langchain.chat_models import ChatOpenAI
    from langchain.embeddings import OpenAIEmbeddings
    from langchain.schema.output_parser import StrOutputParser
    from langchain.schema.runnable import RunnablePassthrough, RunnableLambda
    from langchain.vectorstores import FAISS
    
    # Create a vector retailer and retriever
    vectorstore = FAISS.from_texts(
        ["harrison worked at kensho"], embedding=OpenAIEmbeddings()
    )
    retriever = vectorstore.as_retriever()
    
    # Outline templates for prompts
    template = """Reply the query based mostly solely on the next context:
    {context}
    
    Query: {query}
    """
    immediate = ChatPromptTemplate.from_template(template)
    
    mannequin = ChatOpenAI()
    
    # Create a retrieval-augmented technology chain
    chain = (
        {"context": retriever, "query": RunnablePassthrough()}
        | immediate
        | mannequin
        | StrOutputParser()
    )
    
    end result = chain.invoke("the place did harrison
    
     work?")
    print(end result)
    

    On this instance, the chain retrieves related info from the context and generates a response to the query.

    Conversational Retrieval Chain

    You’ll be able to simply add dialog historical past to your chains. This is an instance of a conversational retrieval chain:

    from langchain.schema.runnable import RunnableMap
    from langchain.schema import format_document
    
    from langchain.prompts.immediate import PromptTemplate
    
    # Outline templates for prompts
    _template = """Given the next dialog and a observe up query, rephrase the observe up query to be a standalone query, in its authentic language.
    
    Chat Historical past:
    {chat_history}
    Comply with Up Enter: {query}
    Standalone query:"""
    CONDENSE_QUESTION_PROMPT = PromptTemplate.from_template(_template)
    
    template = """Reply the query based mostly solely on the next context:
    {context}
    
    Query: {query}
    """
    ANSWER_PROMPT = ChatPromptTemplate.from_template(template)
    
    # Outline enter map and context
    _inputs = RunnableMap(
        standalone_question=RunnablePassthrough.assign(
            chat_history=lambda x: _format_chat_history(x["chat_history"])
        )
        | CONDENSE_QUESTION_PROMPT
        | ChatOpenAI(temperature=0)
        | StrOutputParser(),
    )
    _context =  retriever 
    conversational_qa_chain = _inputs | _context | ANSWER_PROMPT | ChatOpenAI()
    
    end result = conversational_qa_chain.invoke(
        {
            "query": "the place did harrison work?",
            "chat_history": [],
        }
    )
    print(end result)
    

    On this instance, the chain handles a follow-up query inside a conversational context.

    With Reminiscence and Returning Supply Paperwork

    LCEL additionally helps reminiscence and returning supply paperwork. This is how you should utilize reminiscence in a series:

    from operator import itemgetter
    from langchain.reminiscence import ConversationBufferMemory
    
    # Create a reminiscence occasion
    reminiscence = ConversationBufferMemory(
        return_messages=True, output_key="reply", input_key="query"
    )
    
    # Outline steps for the chain
    loaded_memory = RunnablePassthrough.assign(
        chat_history=RunnableLambda(reminiscence.load_memory_variables) | itemgetter("historical past"),
    )
    
    standalone_question = {
        "standalone_question": {
            "query": lambda x: x["question"],
            "chat_history": lambda x: _format_chat_history(x["chat_history"]),
        }
        | CONDENSE_QUESTION_PROMPT
        | ChatOpenAI(temperature=0)
        | StrOutputParser(),
    }
    
    retrieved_documents =  retriever,
        "query": lambda x: x["standalone_question"],
    
    
    final_inputs = {
        "context": lambda x: _combine_documents(x["docs"]),
        "query": itemgetter("query"),
    }
    
    reply =  ANSWER_PROMPT 
    
    # Create the ultimate chain by combining the steps
    final_chain = loaded_memory | standalone_question | retrieved_documents | reply
    
    inputs = {"query": "the place did harrison work?"}
    end result = final_chain.invoke(inputs)
    print(end result)
    

    On this instance, reminiscence is used to retailer and retrieve dialog historical past and supply paperwork.

    A number of Chains

    You’ll be able to string collectively a number of chains utilizing Runnables. This is an instance:

    from operator import itemgetter
    
    from langchain.chat_models import ChatOpenAI
    from langchain.prompts import ChatPromptTemplate
    from langchain.schema import StrOutputParser
    
    prompt1 = ChatPromptTemplate.from_template("what's the metropolis {particular person} is from?")
    prompt2 = ChatPromptTemplate.from_template(
        "what nation is the town {metropolis} in? reply in {language}"
    )
    
    mannequin = ChatOpenAI()
    
    chain1 = prompt1 | mannequin | StrOutputParser()
    
    chain2 = (
        {"metropolis": chain1, "language": itemgetter("language")}
        | prompt2
        | mannequin
        | StrOutputParser()
    )
    
    end result = chain2.invoke({"particular person": "obama", "language": "spanish"})
    print(end result)
    

    On this instance, two chains are mixed to generate details about a metropolis and its nation in a specified language.

    Branching and Merging

    LCEL means that you can cut up and merge chains utilizing RunnableMaps. This is an instance of branching and merging:

    from operator import itemgetter
    
    from langchain.chat_models import ChatOpenAI
    from langchain.prompts import ChatPromptTemplate
    from langchain.schema import StrOutputParser
    
    planner = (
        ChatPromptTemplate.from_template("Generate an argument about: {enter}")
        | ChatOpenAI()
        | StrOutputParser()
        | {"base_response": RunnablePassthrough()}
    )
    
    arguments_for = (
        ChatPromptTemplate.from_template(
            "Record the professionals or constructive facets of {base_response}"
        )
        | ChatOpenAI()
        | StrOutputParser()
    )
    arguments_against = (
        ChatPromptTemplate.from_template(
            "Record the cons or unfavorable facets of {base_response}"
        )
        | ChatOpenAI()
        | StrOutputParser()
    )
    
    final_responder = (
        ChatPromptTemplate.from_messages(
            [
                ("ai", "{original_response}"),
                ("human", "Pros:n{results_1}nnCons:n{results_2}"),
                ("system", "Generate a final response given the critique"),
            ]
        )
        | ChatOpenAI()
        | StrOutputParser()
    )
    
    chain = (
        planner
        | {
            "results_1": arguments_for,
            "results_2": arguments_against,
            "original_response": itemgetter("base_response"),
        }
        | final_responder
    )
    
    end result = chain.invoke({"enter": "scrum"})
    print(end result)
    

    On this instance, a branching and merging chain is used to generate an argument and consider its professionals and cons earlier than producing a last response.

    Writing Python Code with LCEL

    One of many highly effective functions of LangChain Expression Language (LCEL) is writing Python code to unravel person issues. Under is an instance of how one can use LCEL to write down Python code:

    from langchain.chat_models import ChatOpenAI
    from langchain.prompts import ChatPromptTemplate
    from langchain.schema.output_parser import StrOutputParser
    from langchain_experimental.utilities import PythonREPL
    
    template = """Write some python code to unravel the person's drawback. 
    
    Return solely python code in Markdown format, e.g.:
    
    ```python
    ....
    ```"""
    immediate = ChatPromptTemplate.from_messages([("system", template), ("human", "{input}")])
    
    mannequin = ChatOpenAI()
    
    def _sanitize_output(textual content: str):
        _, after = textual content.cut up("```python")
        return after.cut up("```")[0]
    
    chain = immediate | mannequin | StrOutputParser() | _sanitize_output | PythonREPL().run
    
    end result = chain.invoke({"enter": "what's 2 plus 2"})
    print(end result)
    

    On this instance, a person gives enter, and LCEL generates Python code to unravel the issue. The code is then executed utilizing a Python REPL, and the ensuing Python code is returned in Markdown format.

    Please word that utilizing a Python REPL can execute arbitrary code, so use it with warning.

    Including Reminiscence to a Chain

    Reminiscence is important in lots of conversational AI functions. This is how one can add reminiscence to an arbitrary chain:

    from operator import itemgetter
    from langchain.chat_models import ChatOpenAI
    from langchain.reminiscence import ConversationBufferMemory
    from langchain.schema.runnable import RunnablePassthrough, RunnableLambda
    from langchain.prompts import ChatPromptTemplate, MessagesPlaceholder
    
    mannequin = ChatOpenAI()
    immediate = ChatPromptTemplate.from_messages(
        [
            ("system", "You are a helpful chatbot"),
            MessagesPlaceholder(variable_name="history"),
            ("human", "{input}"),
        ]
    )
    
    reminiscence = ConversationBufferMemory(return_messages=True)
    
    # Initialize reminiscence
    reminiscence.load_memory_variables({})
    
    chain = (
        RunnablePassthrough.assign(
            historical past=RunnableLambda(reminiscence.load_memory_variables) | itemgetter("historical past")
        )
        | immediate
        | mannequin
    )
    
    inputs = {"enter": "hello, I am Bob"}
    response = chain.invoke(inputs)
    response
    
    # Save the dialog in reminiscence
    reminiscence.save_context(inputs, {"output": response.content material})
    
    # Load reminiscence to see the dialog historical past
    reminiscence.load_memory_variables({})
    

    On this instance, reminiscence is used to retailer and retrieve dialog historical past, permitting the chatbot to take care of context and reply appropriately.

    Utilizing Exterior Instruments with Runnables

    LCEL means that you can seamlessly combine exterior instruments with Runnables. This is an instance utilizing the DuckDuckGo Search device:

    from langchain.chat_models import ChatOpenAI
    from langchain.prompts import ChatPromptTemplate
    from langchain.schema.output_parser import StrOutputParser
    from langchain.instruments import DuckDuckGoSearchRun
    
    search = DuckDuckGoSearchRun()
    
    template = """Flip the next person enter right into a search question for a search engine:
    
    {enter}"""
    immediate = ChatPromptTemplate.from_template(template)
    
    mannequin = ChatOpenAI()
    
    chain = immediate | mannequin | StrOutputParser() | search
    
    search_result = chain.invoke({"enter": "I would like to determine what video games are tonight"})
    print(search_result)
    

    On this instance, LCEL integrates the DuckDuckGo Search device into the chain, permitting it to generate a search question from person enter and retrieve search outcomes.

    LCEL’s flexibility makes it simple to include numerous exterior instruments and providers into your language processing pipelines, enhancing their capabilities and performance.

    Including Moderation to an LLM Utility

    To make sure that your LLM utility adheres to content material insurance policies and contains moderation safeguards, you may combine moderation checks into your chain. This is how one can add moderation utilizing LangChain:

    from langchain.chains import OpenAIModerationChain
    from langchain.llms import OpenAI
    from langchain.prompts import ChatPromptTemplate
    
    reasonable = OpenAIModerationChain()
    
    mannequin = OpenAI()
    immediate = ChatPromptTemplate.from_messages([("system", "repeat after me: {input}")])
    
    chain = immediate | mannequin
    
    # Authentic response with out moderation
    response_without_moderation = chain.invoke({"enter": "you might be silly"})
    print(response_without_moderation)
    
    moderated_chain = chain | reasonable
    
    # Response after moderation
    response_after_moderation = moderated_chain.invoke({"enter": "you might be silly"})
    print(response_after_moderation)
    

    On this instance, the OpenAIModerationChain is used so as to add moderation to the response generated by the LLM. The moderation chain checks the response for content material that violates OpenAI’s content material coverage. If any violations are discovered, it is going to flag the response accordingly.

    Routing by Semantic Similarity

    LCEL means that you can implement customized routing logic based mostly on the semantic similarity of person enter. This is an instance of how one can dynamically decide the chain logic based mostly on person enter:

    from langchain.chat_models import ChatOpenAI
    from langchain.embeddings import OpenAIEmbeddings
    from langchain.prompts import PromptTemplate
    from langchain.schema.output_parser import StrOutputParser
    from langchain.schema.runnable import RunnableLambda, RunnablePassthrough
    from langchain.utils.math import cosine_similarity
    
    physics_template = """You're a very good physics professor. 
    You're nice at answering questions on physics in a concise and straightforward to know method. 
    When you do not know the reply to a query you admit that you do not know.
    
    Here's a query:
    {question}"""
    
    math_template = """You're a excellent mathematician. You're nice at answering math questions. 
    You're so good as a result of you'll be able to break down arduous issues into their part elements, 
    reply the part elements, after which put them collectively to reply the broader query.
    
    Here's a query:
    {question}"""
    
    embeddings = OpenAIEmbeddings()
    prompt_templates = [physics_template, math_template]
    prompt_embeddings = embeddings.embed_documents(prompt_templates)
    
    def prompt_router(enter):
        query_embedding = embeddings.embed_query(enter["query"])
        similarity = cosine_similarity([query_embedding], prompt_embeddings)[0]
        most_similar = prompt_templates[similarity.argmax()]
        print("Utilizing MATH" if most_similar == math_template else "Utilizing PHYSICS")
        return PromptTemplate.from_template(most_similar)
    
    chain = (
        {"question": RunnablePassthrough()}
        | RunnableLambda(prompt_router)
        | ChatOpenAI()
        | StrOutputParser()
    )
    
    print(chain.invoke({"question": "What's a black gap"}))
    print(chain.invoke({"question": "What's a path integral"}))
    

    On this instance, the prompt_router operate calculates the cosine similarity between person enter and predefined immediate templates for physics and math questions. Based mostly on the similarity rating, the chain dynamically selects probably the most related immediate template, guaranteeing that the chatbot responds appropriately to the person’s query.

    Utilizing Brokers and Runnables

    LangChain means that you can create brokers by combining Runnables, prompts, fashions, and instruments. This is an instance of constructing an agent and utilizing it:

    from langchain.brokers import XMLAgent, device, AgentExecutor
    from langchain.chat_models import ChatAnthropic
    
    mannequin = ChatAnthropic(mannequin="claude-2")
    
    @device
    def search(question: str) -> str:
        """Search issues about present occasions."""
        return "32 levels"
    
    tool_list = [search]
    
    # Get immediate to make use of
    immediate = XMLAgent.get_default_prompt()
    
    # Logic for going from intermediate steps to a string to move into the mannequin
    def convert_intermediate_steps(intermediate_steps):
        log = ""
        for motion, commentary in intermediate_steps:
            log += (
                f"<device>{motion.device}</device><tool_input>{motion.tool_input}"
                f"</tool_input><commentary>{commentary}</commentary>"
            )
        return log
    
    # Logic for changing instruments to a string to go within the immediate
    def convert_tools(instruments):
        return "n".be part of([f"{tool.name}: {tool.description}" for tool in tools])
    
    agent = (
        {
            "query": lambda x: x["question"],
            "intermediate_steps": lambda x: convert_intermediate_steps(
                x["intermediate_steps"]
            ),
        }
        | immediate.partial(instruments=convert_tools(tool_list))
        | mannequin.bind(cease=["</tool_input>", "</final_answer>"])
        | XMLAgent.get_default_output_parser()
    )
    
    agent_executor = AgentExecutor(agent=agent, instruments=tool_list, verbose=True)
    
    end result = agent_executor.invoke({"query": "What is the climate in New York?"})
    print(end result)
    

    On this instance, an agent is created by combining a mannequin, instruments, a immediate, and a customized logic for intermediate steps and power conversion. The agent is then executed, offering a response to the person’s question.

    Querying a SQL Database

    You need to use LangChain to question a SQL database and generate SQL queries based mostly on person questions. This is an instance:

    from langchain.prompts import ChatPromptTemplate
    
    template = """Based mostly on the desk schema beneath, write a SQL question that might reply the person's query:
    {schema}
    
    Query: {query}
    SQL Question:"""
    immediate = ChatPromptTemplate.from_template(template)
    
    from langchain.utilities import SQLDatabase
    
    # Initialize the database (you may want the Chinook pattern DB for this instance)
    db = SQLDatabase.from_uri("sqlite:///./Chinook.db")
    
    def get_schema(_):
        return db.get_table_info()
    
    def run_query(question):
        return db.run(question)
    
    from langchain.chat_models import ChatOpenAI
    from langchain.schema.output_parser import StrOutputParser
    from langchain.schema.runnable import RunnablePassthrough
    
    mannequin = ChatOpenAI()
    
    sql_response = (
        RunnablePassthrough.assign(schema=get_schema)
        | immediate
        | mannequin.bind(cease=["nSQLResult:"])
        | StrOutputParser()
    )
    
    end result = sql_response.invoke({"query": "What number of workers are there?"})
    print(end result)
    
    template = """Based mostly on the desk schema beneath, query, SQL question, and SQL response, write a pure language response:
    {schema}
    
    Query: {query}
    SQL Question: {question}
    SQL Response: {response}"""
    prompt_response = ChatPromptTemplate.from_template(template)
    
    full_chain = (
        RunnablePassthrough.assign(question=sql_response)
        | RunnablePassthrough.assign(
            schema=get_schema,
            response=lambda x: db.run(x["query"]),
        )
        | prompt_response
        | mannequin
    )
    
    response = full_chain.invoke({"query": "What number of workers are there?"})
    print(response)
    

    On this instance, LangChain is used to generate SQL queries based mostly on person questions and retrieve responses from a SQL database. The prompts and responses are formatted to supply pure language interactions with the database.


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    LangServe & LangSmith

    LangServe helps builders deploy LangChain runnables and chains as a REST API. This library is built-in with FastAPI and makes use of pydantic for information validation. Moreover, it gives a shopper that can be utilized to name into runnables deployed on a server, and a JavaScript shopper is out there in LangChainJS.

    Options

    • Enter and Output schemas are robotically inferred out of your LangChain object and enforced on each API name, with wealthy error messages.
    • An API docs web page with JSONSchema and Swagger is out there.
    • Environment friendly /invoke, /batch, and /stream endpoints with assist for a lot of concurrent requests on a single server.
    • /stream_log endpoint for streaming all (or some) intermediate steps out of your chain/agent.
    • Playground web page at /playground with streaming output and intermediate steps.
    • Constructed-in (non-obligatory) tracing to LangSmith; simply add your API key (see Directions).
    • All constructed with battle-tested open-source Python libraries like FastAPI, Pydantic, uvloop, and asyncio.

    Limitations

    • Consumer callbacks usually are not but supported for occasions that originate on the server.
    • OpenAPI docs is not going to be generated when utilizing Pydantic V2. FastAPI doesn’t assist mixing pydantic v1 and v2 namespaces. See the part beneath for extra particulars.

    Use the LangChain CLI to bootstrap a LangServe undertaking shortly. To make use of the langchain CLI, just remember to have a current model of langchain-cli put in. You’ll be able to set up it with pip set up -U langchain-cli.

    langchain app new ../path/to/listing
    

    Get your LangServe occasion began shortly with LangChain Templates. For extra examples, see the templates index or the examples listing.

    This is a server that deploys an OpenAI chat mannequin, an Anthropic chat mannequin, and a series that makes use of the Anthropic mannequin to inform a joke a couple of matter.

    #!/usr/bin/env python
    from fastapi import FastAPI
    from langchain.prompts import ChatPromptTemplate
    from langchain.chat_models import ChatAnthropic, ChatOpenAI
    from langserve import add_routes
    
    app = FastAPI(
      title="LangChain Server",
      model="1.0",
      description="A easy api server utilizing Langchain's Runnable interfaces",
    )
    
    add_routes(
        app,
        ChatOpenAI(),
        path="/openai",
    )
    
    add_routes(
        app,
        ChatAnthropic(),
        path="/anthropic",
    )
    
    mannequin = ChatAnthropic()
    immediate = ChatPromptTemplate.from_template("inform me a joke about {matter}")
    add_routes(
        app,
        immediate | mannequin,
        path="/chain",
    )
    
    if __name__ == "__main__":
        import uvicorn
    
        uvicorn.run(app, host="localhost", port=8000)
    

    As soon as you have deployed the server above, you may view the generated OpenAPI docs utilizing:

    curl localhost:8000/docs
    

    Make sure that so as to add the /docs suffix.

    from langchain.schema import SystemMessage, HumanMessage
    from langchain.prompts import ChatPromptTemplate
    from langchain.schema.runnable import RunnableMap
    from langserve import RemoteRunnable
    
    openai = RemoteRunnable("http://localhost:8000/openai/")
    anthropic = RemoteRunnable("http://localhost:8000/anthropic/")
    joke_chain = RemoteRunnable("http://localhost:8000/chain/")
    
    joke_chain.invoke({"matter": "parrots"})
    
    # or async
    await joke_chain.ainvoke({"matter": "parrots"})
    
    immediate = [
        SystemMessage(content="Act like either a cat or a parrot."),
        HumanMessage(content="Hello!")
    ]
    
    # Helps astream
    async for msg in anthropic.astream(immediate):
        print(msg, finish="", flush=True)
    
    immediate = ChatPromptTemplate.from_messages(
        [("system", "Tell me a long story about {topic}")]
    )
    
    # Can outline customized chains
    chain = immediate | RunnableMap({
        "openai": openai,
        "anthropic": anthropic,
    })
    
    chain.batch([{ "topic": "parrots" }, { "topic": "cats" }])
    

    In TypeScript (requires LangChain.js model 0.0.166 or later):

    import { RemoteRunnable } from "langchain/runnables/distant";
    
    const chain = new RemoteRunnable({
      url: `http://localhost:8000/chain/invoke/`,
    });
    const end result = await chain.invoke({
      matter: "cats",
    });
    

    Python utilizing requests:

    import requests
    response = requests.put up(
        "http://localhost:8000/chain/invoke/",
        json={'enter': {'matter': 'cats'}}
    )
    response.json()
    

    You may also use curl:

    curl --location --request POST 'http://localhost:8000/chain/invoke/' 
        --header 'Content material-Sort: utility/json' 
        --data-raw '{
            "enter": {
                "matter": "cats"
            }
        }'
    

    The next code:

    ...
    add_routes(
      app,
      runnable,
      path="/my_runnable",
    )
    

    provides of those endpoints to the server:

    • POST /my_runnable/invoke – invoke the runnable on a single enter
    • POST /my_runnable/batch – invoke the runnable on a batch of inputs
    • POST /my_runnable/stream – invoke on a single enter and stream the output
    • POST /my_runnable/stream_log – invoke on a single enter and stream the output, together with output of intermediate steps because it’s generated
    • GET /my_runnable/input_schema – json schema for enter to the runnable
    • GET /my_runnable/output_schema – json schema for output of the runnable
    • GET /my_runnable/config_schema – json schema for config of the runnable

    You will discover a playground web page to your runnable at /my_runnable/playground. This exposes a easy UI to configure and invoke your runnable with streaming output and intermediate steps.

    For each shopper and server:

    pip set up "langserve[all]"
    

    or pip set up “langserve[client]” for shopper code, and pip set up “langserve[server]” for server code.

    If it’s worthwhile to add authentication to your server, please reference FastAPI’s safety documentation and middleware documentation.

    You’ll be able to deploy to GCP Cloud Run utilizing the next command:

    gcloud run deploy [your-service-name] --source . --port 8001 --allow-unauthenticated --region us-central1 --set-env-vars=OPENAI_API_KEY=your_key
    

    LangServe gives assist for Pydantic 2 with some limitations. OpenAPI docs is not going to be generated for invoke/batch/stream/stream_log when utilizing Pydantic V2. Quick API doesn’t assist mixing pydantic v1 and v2 namespaces. LangChain makes use of the v1 namespace in Pydantic v2. Please learn the next pointers to make sure compatibility with LangChain. Aside from these limitations, we anticipate the API endpoints, the playground, and some other options to work as anticipated.

    LLM functions typically cope with recordsdata. There are totally different architectures that may be made to implement file processing; at a excessive degree:

    • The file could also be uploaded to the server by way of a devoted endpoint and processed utilizing a separate endpoint.
    • The file could also be uploaded by both worth (bytes of file) or reference (e.g., s3 url to file content material).
    • The processing endpoint could also be blocking or non-blocking.
    • If vital processing is required, the processing could also be offloaded to a devoted course of pool.

    You must decide what’s the acceptable structure to your utility. At the moment, to add recordsdata by worth to a runnable, use base64 encoding for the file (multipart/form-data shouldn’t be supported but).

    This is an instance that reveals how one can use base64 encoding to ship a file to a distant runnable. Bear in mind, you may at all times add recordsdata by reference (e.g., s3 url) or add them as multipart/form-data to a devoted endpoint.

    Enter and Output varieties are outlined on all runnables. You’ll be able to entry them by way of the input_schema and output_schema properties. LangServe makes use of these varieties for validation and documentation. If you wish to override the default inferred varieties, you should utilize the with_types technique.

    This is a toy instance as an instance the concept:

    from typing import Any
    from fastapi import FastAPI
    from langchain.schema.runnable import RunnableLambda
    
    app = FastAPI()
    
    def func(x: Any) -> int:
        """Mistyped operate that ought to settle for an int however accepts something."""
        return x + 1
    
    runnable = RunnableLambda(func).with_types(
        input_schema=int,
    )
    
    add_routes(app, runnable)
    

    Inherit from CustomUserType if you need the information to deserialize right into a pydantic mannequin moderately than the equal dict illustration. In the mean time, this kind solely works server-side and is used to specify desired decoding habits. If inheriting from this kind, the server will hold the decoded sort as a pydantic mannequin as a substitute of changing it right into a dict.

    from fastapi import FastAPI
    from langchain.schema.runnable import RunnableLambda
    from langserve import add_routes
    from langserve.schema import CustomUserType
    
    app = FastAPI()
    
    class Foo(CustomUserType):
        bar: int
    
    def func(foo: Foo) -> int:
        """Pattern operate that expects a Foo sort which is a pydantic mannequin"""
        assert isinstance(foo, Foo)
        return foo.bar
    
    add_routes(app, RunnableLambda(func), path="/foo")
    

    The playground means that you can outline customized widgets to your runnable from the backend. A widget is specified on the subject degree and shipped as a part of the JSON schema of the enter sort. A widget should comprise a key known as sort with the worth being one in all a well known listing of widgets. Different widget keys shall be related to values that describe paths in a JSON object.

    Common schema:

    sort JsonPath = quantity | string | (quantity | string)[];
    sort NameSpacedPath = { title: string; path: JsonPath }; // Utilizing title to imitate json schema, however can use namespace
    sort OneOfPath = { oneOf: JsonPath[] };
    
    sort Widget =  OneOfPath;
    ;
    

    Permits the creation of a file add enter within the UI playground for recordsdata which can be uploaded as base64 encoded strings. This is the complete instance.

    strive:
        from pydantic.v1 import Subject
    besides ImportError:
        from pydantic import Subject
    
    from langserve import CustomUserType
    
    # ATTENTION: Inherit from CustomUserType as a substitute of BaseModel in any other case
    # the server will decode it right into a dict as a substitute of a pydantic mannequin.
    class FileProcessingRequest(CustomUserType):
        """Request together with a base64 encoded file."""
    
        # The additional subject is used to specify a widget for the playground UI.
        file: str = Subject(..., further={"widget": {"sort": "base64file"}})
        num_chars: int = 100
    

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    Introduction to LangSmith

    LangChain makes it simple to prototype LLM functions and Brokers. Nonetheless, delivering LLM functions to manufacturing may be deceptively troublesome. You’ll possible should closely customise and iterate in your prompts, chains, and different elements to create a high-quality product.

    To help on this course of, LangSmith was launched, a unified platform for debugging, testing, and monitoring your LLM functions.

    When would possibly this come in useful? It’s possible you’ll discover it helpful whenever you need to shortly debug a brand new chain, agent, or set of instruments, visualize how elements (chains, llms, retrievers, and so forth.) relate and are used, consider totally different prompts and LLMs for a single part, run a given chain a number of instances over a dataset to make sure it constantly meets a top quality bar, or seize utilization traces and use LLMs or analytics pipelines to generate insights.

    Conditions:

    1. Create a LangSmith account and create an API key (see backside left nook).
    2. Familiarize your self with the platform by trying by way of the docs.

    Now, let’s get began!

    First, configure your setting variables to inform LangChain to log traces. That is completed by setting the LANGCHAIN_TRACING_V2 setting variable to true. You’ll be able to inform LangChain which undertaking to log to by setting the LANGCHAIN_PROJECT setting variable (if this is not set, runs shall be logged to the default undertaking). This may robotically create the undertaking for you if it would not exist. You will need to additionally set the LANGCHAIN_ENDPOINT and LANGCHAIN_API_KEY setting variables.

    NOTE: You may also use a context supervisor in python to log traces utilizing:

    from langchain.callbacks.supervisor import tracing_v2_enabled
    
    with tracing_v2_enabled(project_name="My Mission"):
        agent.run("How many individuals reside in canada as of 2023?")
    

    Nonetheless, on this instance, we are going to use setting variables.

    %pip set up openai tiktoken pandas duckduckgo-search --quiet
    
    import os
    from uuid import uuid4
    
    unique_id = uuid4().hex[0:8]
    os.environ["LANGCHAIN_TRACING_V2"] = "true"
    os.environ["LANGCHAIN_PROJECT"] = f"Tracing Walkthrough - {unique_id}"
    os.environ["LANGCHAIN_ENDPOINT"] = "https://api.smith.langchain.com"
    os.environ["LANGCHAIN_API_KEY"] = "<YOUR-API-KEY>"  # Replace to your API key
    
    # Utilized by the agent on this tutorial
    os.environ["OPENAI_API_KEY"] = "<YOUR-OPENAI-API-KEY>"
    

    Create the LangSmith shopper to work together with the API:

    from langsmith import Consumer
    
    shopper = Consumer()
    

    Create a LangChain part and log runs to the platform. On this instance, we are going to create a ReAct-style agent with entry to a basic search device (DuckDuckGo). The agent’s immediate may be seen within the Hub right here:

    from langchain import hub
    from langchain.brokers import AgentExecutor
    from langchain.brokers.format_scratchpad import format_to_openai_function_messages
    from langchain.brokers.output_parsers import OpenAIFunctionsAgentOutputParser
    from langchain.chat_models import ChatOpenAI
    from langchain.instruments import DuckDuckGoSearchResults
    from langchain.instruments.render import format_tool_to_openai_function
    
    # Fetches the newest model of this immediate
    immediate = hub.pull("wfh/langsmith-agent-prompt:newest")
    
    llm = ChatOpenAI(
        mannequin="gpt-3.5-turbo-16k",
        temperature=0,
    )
    
    instruments = [
        DuckDuckGoSearchResults(
            name="duck_duck_go"
        ),  # General internet search using DuckDuckGo
    ]
    
    llm_with_tools = llm.bind(features=[format_tool_to_openai_function(t) for t in tools])
    
    runnable_agent = (
        {
            "enter": lambda x: x["input"],
            "agent_scratchpad": lambda x: format_to_openai_function_messages(
                x["intermediate_steps"]
            ),
        }
        | immediate
        | llm_with_tools
        | OpenAIFunctionsAgentOutputParser()
    )
    
    agent_executor = AgentExecutor(
        agent=runnable_agent, instruments=instruments, handle_parsing_errors=True
    )
    

    We’re operating the agent concurrently on a number of inputs to cut back latency. Runs get logged to LangSmith within the background, so execution latency is unaffected:

    inputs = [
        "What is LangChain?",
        "What's LangSmith?",
        "When was Llama-v2 released?",
        "What is the langsmith cookbook?",
        "When did langchain first announce the hub?",
    ]
    
    outcomes = agent_executor.batch([{"input": x} for x in inputs], return_exceptions=True)
    
    outcomes[:2]
    

    Assuming you have efficiently arrange your setting, your agent traces ought to present up within the Tasks part within the app. Congrats!

    It seems just like the agent is not successfully utilizing the instruments although. Let’s consider this so we’ve a baseline.

    Along with logging runs, LangSmith additionally means that you can check and consider your LLM functions.

    On this part, you’ll leverage LangSmith to create a benchmark dataset and run AI-assisted evaluators on an agent. You’ll achieve this in just a few steps:

    • Create a LangSmith dataset:

    Under, we use the LangSmith shopper to create a dataset from the enter questions from above and an inventory labels. You’ll use these later to measure efficiency for a brand new agent. A dataset is a set of examples, that are nothing greater than input-output pairs you should utilize as check instances to your utility:

    outputs = [
        "LangChain is an open-source framework for building applications using large language models. It is also the name of the company building LangSmith.",
        "LangSmith is a unified platform for debugging, testing, and monitoring language model applications and agents powered by LangChain",
        "July 18, 2023",
        "The langsmith cookbook is a github repository containing detailed examples of how to use LangSmith to debug, evaluate, and monitor large language model-powered applications.",
        "September 5, 2023",
    ]
    
    dataset_name = f"agent-qa-{unique_id}"
    
    dataset = shopper.create_dataset(
        dataset_name,
        description="An instance dataset of questions over the LangSmith documentation.",
    )
    
    for question, reply in zip(inputs, outputs):
        shopper.create_example(
            inputs={"enter": question}, outputs={"output": reply}, dataset_id=dataset.id
        )
    
    • Initialize a brand new agent to benchmark:

    LangSmith helps you to consider any LLM, chain, agent, or perhaps a customized operate. Conversational brokers are stateful (they’ve reminiscence); to make sure that this state is not shared between dataset runs, we are going to move in a chain_factory (

    aka a constructor) operate to initialize for every name:

    # Since chains may be stateful (e.g. they will have reminiscence), we offer
    # a solution to initialize a brand new chain for every row within the dataset. That is completed
    # by passing in a manufacturing unit operate that returns a brand new chain for every row.
    def agent_factory(immediate):
        llm_with_tools = llm.bind(
            features=[format_tool_to_openai_function(t) for t in tools]
        )
        runnable_agent = (
            {
                "enter": lambda x: x["input"],
                "agent_scratchpad": lambda x: format_to_openai_function_messages(
                    x["intermediate_steps"]
                ),
            }
            | immediate
            | llm_with_tools
            | OpenAIFunctionsAgentOutputParser()
        )
        return AgentExecutor(agent=runnable_agent, instruments=instruments, handle_parsing_errors=True)
    

    Manually evaluating the outcomes of chains within the UI is efficient, however it may be time-consuming. It may be useful to make use of automated metrics and AI-assisted suggestions to guage your part’s efficiency:

    from langchain.analysis import EvaluatorType
    from langchain.smith import RunEvalConfig
    
    evaluation_config = RunEvalConfig(
        evaluators=[
            EvaluatorType.QA,
            EvaluatorType.EMBEDDING_DISTANCE,
            RunEvalConfig.LabeledCriteria("helpfulness"),
            RunEvalConfig.LabeledScoreString(
                {
                    "accuracy": """
    Score 1: The answer is completely unrelated to the reference.
    Score 3: The answer has minor relevance but does not align with the reference.
    Score 5: The answer has moderate relevance but contains inaccuracies.
    Score 7: The answer aligns with the reference but has minor errors or omissions.
    Score 10: The answer is completely accurate and aligns perfectly with the reference."""
                },
                normalize_by=10,
            ),
        ],
        custom_evaluators=[],
    )
    
    • Run the agent and evaluators:

    Use the run_on_dataset (or asynchronous arun_on_dataset) operate to guage your mannequin. This may:

    1. Fetch instance rows from the desired dataset.
    2. Run your agent (or any customized operate) on every instance.
    3. Apply evaluators to the ensuing run traces and corresponding reference examples to generate automated suggestions.

    The outcomes shall be seen within the LangSmith app:

    chain_results = run_on_dataset(
        dataset_name=dataset_name,
        llm_or_chain_factory=functools.partial(agent_factory, immediate=immediate),
        analysis=evaluation_config,
        verbose=True,
        shopper=shopper,
        project_name=f"runnable-agent-test-5d466cbc-{unique_id}",
        tags=[
            "testing-notebook",
            "prompt:5d466cbc",
        ],
    )
    

    Now that we’ve our check run outcomes, we are able to make adjustments to our agent and benchmark them. Let’s do that once more with a special immediate and see the outcomes:

    candidate_prompt = hub.pull("wfh/langsmith-agent-prompt:39f3bbd0")
    
    chain_results = run_on_dataset(
        dataset_name=dataset_name,
        llm_or_chain_factory=functools.partial(agent_factory, immediate=candidate_prompt),
        analysis=evaluation_config,
        verbose=True,
        shopper=shopper,
        project_name=f"runnable-agent-test-39f3bbd0-{unique_id}",
        tags=[
            "testing-notebook",
            "prompt:39f3bbd0",
        ],
    )
    

    LangSmith helps you to export information to widespread codecs equivalent to CSV or JSONL straight within the net app. You may also use the shopper to fetch runs for additional evaluation, to retailer in your individual database, or to share with others. Let’s fetch the run traces from the analysis run:

    runs = shopper.list_runs(project_name=chain_results["project_name"], execution_order=1)
    
    # After a while, these shall be populated.
    shopper.read_project(project_name=chain_results["project_name"]).feedback_stats
    

    This was a fast information to get began, however there are various extra methods to make use of LangSmith to hurry up your developer circulation and produce higher outcomes.

    For extra info on how one can get probably the most out of LangSmith, try LangSmith documentation.

    Degree up with Nanonets

    Whereas LangChain is a priceless device for integrating language fashions (LLMs) along with your functions, it might face limitations with regards to enterprise use instances. Let’s discover how Nanonets goes past LangChain to deal with these challenges:

    1. Complete Information Connectivity:
    LangChain presents connectors, however it might not cowl all of the workspace apps and information codecs that companies depend on. Nanonets gives information connectors for over 100 extensively used workspace apps, together with Slack, Notion, Google Suite, Salesforce, Zendesk, and lots of extra. It additionally helps all unstructured information varieties like PDFs, TXTs, photographs, audio recordsdata, and video recordsdata, in addition to structured information varieties like CSVs, spreadsheets, MongoDB, and SQL databases.

    2. Job Automation for Workspace Apps:
    Whereas textual content / response technology works nice, LangChain’s capabilities are restricted with regards to utilizing pure language to carry out duties in numerous functions. Nanonets presents set off/motion brokers for the preferred workspace apps, permitting you to arrange workflows that hear for occasions and carry out actions. For instance, you may automate e-mail responses, CRM entries, SQL queries, and extra, all by way of pure language instructions.

    3. Actual-time Information Sync:
    LangChain fetches static information with information connectors, which can not sustain with information adjustments within the supply database. In distinction, Nanonets ensures real-time synchronization with information sources, guaranteeing that you simply’re at all times working with the newest info.

    3. Simplified Configuration:
    Configuring the weather of the LangChain pipeline, equivalent to retrievers and synthesizers, is usually a complicated and time-consuming course of. Nanonets streamlines this by offering optimized information ingestion and indexing for every information sort, all dealt with within the background by the AI Assistant. This reduces the burden of fine-tuning and makes it simpler to arrange and use.

    4. Unified Answer:
    Not like LangChain, which can require distinctive implementations for every process, Nanonets serves as a one-stop answer for connecting your information with LLMs. Whether or not it’s worthwhile to create LLM functions or AI workflows, Nanonets presents a unified platform to your various wants.

    Nanonets AI Workflows

    Nanonets Workflows is a safe, multi-purpose AI Assistant that simplifies the combination of your information and information with LLMs and facilitates creation of no-code functions and workflows. It presents an easy-to-use person interface, making it accessible for each people and organizations.

    To get began, you may schedule a name with one in all our AI specialists, who can present a personalised demo and trial of Nanonets Workflows tailor-made to your particular use case.

    As soon as arrange, you should utilize pure language to design and execute complicated functions and workflows powered by LLMs, integrating seamlessly along with your apps and information.

    Supercharge your groups with Nanonets AI to create apps and combine your information with AI-driven functions and workflows, permitting your groups to give attention to what actually issues.


    Automate guide duties and workflows with our AI-driven workflow builder, designed by Nanonets for you and your groups.


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