DocArray Hnsw 搜索
DocArrayHnswSearch 是由 Docarray 提供的一种轻量级文档索引实现，完全本地运行，并且最适合用于小型到中型的数据集。它在 hnswlib 中存储向量，在 SQLite 中存储所有其他数据。
您需要使用 langchain-community 安装 pip install -qU langchain-community 才能使用此集成
这个笔记本展示了如何使用与DocArrayHnswSearch相关的功能。
设置
未取消注释下方单元格以安装 DocArray 并设置/获取您的 OpenAI API 密钥（如果您还没有这样做的话）。
%pip install --upgrade --quiet "docarray[hnswlib]"
# Get an OpenAI token: https://platform.openai.com/account/api-keys
# import os
# from getpass import getpass
# OPENAI_API_KEY = getpass()
# os.environ["OPENAI_API_KEY"] = OPENAI_API_KEY
用DocArrayHnswSearch
from langchain_community.document_loaders import TextLoader
from langchain_community.vectorstores import DocArrayHnswSearch
from langchain_openai import OpenAIEmbeddings
from langchain_text_splitters import CharacterTextSplitter
documents = TextLoader("../../how_to/state_of_the_union.txt").load()
text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
docs = text_splitter.split_documents(documents)
embeddings = OpenAIEmbeddings()
db = DocArrayHnswSearch.from_documents(
docs, embeddings, work_dir="hnswlib_store/", n_dim=1536
)
相似度搜索
query = "What did the president say about Ketanji Brown Jackson"
docs = db.similarity_search(query)
print(docs[0].page_content)
Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections.
Tonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service.
One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court.
And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.
相似性搜索（带分数）
The returned distance score is cosine distance. Therefore, a lower score is better.
docs = db.similarity_search_with_score(query)
docs[0]
(Document(page_content='Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. \n\nTonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. \n\nOne of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. \n\nAnd I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.', metadata={}),
0.36962226)
import shutil
# delete the dir
shutil.rmtree("hnswlib_store")