NomicEmbeddings
这将帮助您开始使用LangChain的Nomic嵌入模型。有关NomicEmbeddings
功能和配置选项的详细文档,请参阅API参考。
概述
集成详情
提供商 | 包 |
---|---|
Nomic | langchain-nomic |
设置
要访问Nomic嵌入模型,您需要创建一个Nomic账户,获取一个API密钥,并安装langchain-nomic
集成包。
凭证
前往 https://atlas.nomic.ai/ 注册 Nomic 并生成一个 API 密钥。完成此操作后,设置 NOMIC_API_KEY
环境变量:
import getpass
import os
if not os.getenv("NOMIC_API_KEY"):
os.environ["NOMIC_API_KEY"] = getpass.getpass("Enter your Nomic API key: ")
如果你想获取模型调用的自动追踪,你也可以通过取消注释以下内容来设置你的LangSmith API密钥:
# os.environ["LANGCHAIN_TRACING_V2"] = "true"
# os.environ["LANGCHAIN_API_KEY"] = getpass.getpass("Enter your LangSmith API key: ")
安装
LangChain Nomic 集成位于 langchain-nomic
包中:
%pip install -qU langchain-nomic
Note: you may need to restart the kernel to use updated packages.
实例化
现在我们可以实例化我们的模型对象并生成聊天完成:
from langchain_nomic import NomicEmbeddings
embeddings = NomicEmbeddings(
model="nomic-embed-text-v1.5",
# dimensionality=256,
# Nomic's `nomic-embed-text-v1.5` model was [trained with Matryoshka learning](https://blog.nomic.ai/posts/nomic-embed-matryoshka)
# to enable variable-length embeddings with a single model.
# This means that you can specify the dimensionality of the embeddings at inference time.
# The model supports dimensionality from 64 to 768.
# inference_mode="remote",
# One of `remote`, `local` (Embed4All), or `dynamic` (automatic). Defaults to `remote`.
# api_key=... , # if using remote inference,
# device="cpu",
# The device to use for local embeddings. Choices include
# `cpu`, `gpu`, `nvidia`, `amd`, or a specific device name. See
# the docstring for `GPT4All.__init__` for more info. Typically
# defaults to CPU. Do not use on macOS.
)
API Reference:NomicEmbeddings
索引与检索
嵌入模型通常用于检索增强生成(RAG)流程中,既作为索引数据的一部分,也用于后续的检索。有关更详细的说明,请参阅我们的RAG教程。
下面,看看如何使用我们上面初始化的embeddings
对象来索引和检索数据。在这个例子中,我们将在InMemoryVectorStore
中索引和检索一个示例文档。
# Create a vector store with a sample text
from langchain_core.vectorstores import InMemoryVectorStore
text = "LangChain is the framework for building context-aware reasoning applications"
vectorstore = InMemoryVectorStore.from_texts(
[text],
embedding=embeddings,
)
# Use the vectorstore as a retriever
retriever = vectorstore.as_retriever()
# Retrieve the most similar text
retrieved_documents = retriever.invoke("What is LangChain?")
# show the retrieved document's content
retrieved_documents[0].page_content
API Reference:InMemoryVectorStore
'LangChain is the framework for building context-aware reasoning applications'
直接使用
在底层,向量存储和检索器实现正在调用 embeddings.embed_documents(...)
和 embeddings.embed_query(...)
来分别为 from_texts
和检索 invoke
操作中使用的文本创建嵌入。
你可以直接调用这些方法来获取嵌入,用于你自己的用例。
嵌入单个文本
你可以使用embed_query
嵌入单个文本或文档:
single_vector = embeddings.embed_query(text)
print(str(single_vector)[:100]) # Show the first 100 characters of the vector
[0.024642944, 0.029083252, -0.14013672, -0.09082031, 0.058898926, -0.07489014, -0.0138168335, 0.0037
嵌入多个文本
你可以使用embed_documents
嵌入多个文本:
text2 = (
"LangGraph is a library for building stateful, multi-actor applications with LLMs"
)
two_vectors = embeddings.embed_documents([text, text2])
for vector in two_vectors:
print(str(vector)[:100]) # Show the first 100 characters of the vector
[0.012771606, 0.023727417, -0.12365723, -0.083740234, 0.06530762, -0.07110596, -0.021896362, -0.0068
[-0.019058228, 0.04058838, -0.15222168, -0.06842041, -0.012130737, -0.07128906, -0.04534912, 0.00522
API 参考
有关NomicEmbeddings
功能和配置选项的详细文档,请参阅API参考。