Vectara
Vectara 是值得信赖的 AI 助手和代理平台，专注于为企业关键任务应用程序提供支持。 Vectara 无服务器 RAG 即服务通过一个易于使用的 API 提供了 RAG 的所有组件，包括：
- 一种从文件（PDF、PPT、DOCX 等）中提取文本的方法
- 基于机器学习的分块技术，提供最先进的性能。
- 回旋镖 嵌入模型。
- 它自己的内部向量数据库，用于存储文本块和嵌入向量。
- 一种查询服务，可自动将查询编码为嵌入，并检索最相关的文本片段，支持混合搜索以及多种重排序选项，例如多语言相关性重排序器、MMR、UDF重排序器。
- 一个基于检索到的文档（上下文）创建生成式摘要的大型语言模型，包含引用。
更多信息：
本笔记本展示了如何使用基本的检索功能，当仅将Vectara用作向量存储（不带摘要功能）时，包括：similarity_search 和 similarity_search_with_score 以及使用LangChain的 as_retriever 功能。
设置
要使用 VectaraVectorStore，首先需要安装配套包。
!uv pip install -U pip && uv pip install -qU langchain-vectara
入门指南
开始使用以下步骤：
- 如果您还没有账号，注册免费的Vectara试用。
- 在您的账户中，您可以创建一个或多个语料库。每个语料库代表一个存储从输入文档中提取的文本数据的区域。要创建语料库，请使用“创建语料库”按钮。然后，您需要为语料库提供名称和描述。您还可以选择定义过滤属性并应用一些高级选项。如果单击您创建的语料库，您可以在顶部直接看到其名称和语料库ID。
- 接下来，您需要创建API密钥以访问语料库。在语料库视图中点击“访问控制”选项卡，然后点击“创建API密钥”按钮。为您的密钥命名，并选择您希望密钥是仅用于查询还是查询+索引。点击“创建”，您现在已拥有一个有效的API密钥。请妥善保密此密钥。
要将LangChain与Vectara一起使用，您需要具备以下两个值：corpus_key 和 api_key。
您可以通过两种方式向LangChain提供VECTARA_API_KEY：
-
在您的环境中包含这两个变量：
VECTARA_API_KEY。例如，您可以使用 os.environ 和 getpass 设置这些变量，如下所示：
import os
import getpass
os.environ["VECTARA_API_KEY"] = getpass.getpass("Vectara API Key:")
- 将它们添加到
Vectara向量存储构造函数中：
vectara = Vectara(
vectara_api_key=vectara_api_key
)
在本笔记本中，我们假设它们是在环境中提供的。
import os
os.environ["VECTARA_API_KEY"] = "<VECTARA_API_KEY>"
os.environ["VECTARA_CORPUS_KEY"] = "VECTARA_CORPUS_KEY"
from langchain_vectara import Vectara
from langchain_vectara.vectorstores import (
ChainReranker,
CorpusConfig,
CustomerSpecificReranker,
File,
GenerationConfig,
MmrReranker,
SearchConfig,
VectaraQueryConfig,
)
vectara = Vectara(vectara_api_key=os.getenv("VECTARA_API_KEY"))
首先，我们将联盟文本加载到Vectara中。
请注意，我们使用的是 add_files 接口，该接口不需要任何本地处理或分块操作——Vectara 会接收文件内容，并执行所有必要的预处理、分块以及将文件嵌入到其知识库中。
在这种情况下，它使用了一个 .txt 文件，但同样适用于许多其他文件类型。
corpus_key = os.getenv("VECTARA_CORPUS_KEY")
file_obj = File(
file_path="../document_loaders/example_data/state_of_the_union.txt",
metadata={"source": "text_file"},
)
vectara.add_files([file_obj], corpus_key)
['state_of_the_union.txt']
Vectara RAG（检索增强生成）
我们现在创建一个 VectaraQueryConfig 对象来控制检索和汇总选项：
- 我们启用了总结功能，指定希望LLM选择最匹配的7个片段并用英语回答。
使用此配置，让我们创建一个 LangChain Runnable 对象，该对象通过 as_rag 方法封装了完整的 Vectara RAG 管道：
generation_config = GenerationConfig(
max_used_search_results=7,
response_language="eng",
generation_preset_name="vectara-summary-ext-24-05-med-omni",
enable_factual_consistency_score=True,
)
search_config = SearchConfig(
corpora=[CorpusConfig(corpus_key=corpus_key)],
limit=25,
reranker=ChainReranker(
rerankers=[
CustomerSpecificReranker(reranker_id="rnk_272725719", limit=100),
MmrReranker(diversity_bias=0.2, limit=100),
]
),
)
config = VectaraQueryConfig(
search=search_config,
generation=generation_config,
)
query_str = "what did Biden say?"
rag = vectara.as_rag(config)
rag.invoke(query_str)["answer"]
"President Biden discussed several key issues in his recent statements. He emphasized the importance of keeping schools open and noted that with a high vaccination rate and reduced hospitalizations, most Americans can safely return to normal activities without masks [1]. He addressed the need to hold social media platforms accountable for their impact on children and called for stronger privacy protections and mental health services [2]. Biden also announced measures against Russian oligarchs, including closing American airspace to Russian flights and targeting their assets, as part of efforts to weaken Russia's economy [3], [7]. Additionally, he reaffirmed the need to protect women's rights, particularly the right to choose as affirmed in Roe v. Wade [5]."
我们也可以像这样使用流式接口：
output = {}
curr_key = None
for chunk in rag.stream(query_str):
for key in chunk:
if key not in output:
output[key] = chunk[key]
else:
output[key] += chunk[key]
if key == "answer":
print(chunk[key], end="", flush=True)
curr_key = key
President Biden discussed several key issues in his recent statements. He emphasized the importance of keeping schools open and noted that with a high vaccination rate and reduced hospitalizations, most Americans can safely return to normal activities without masks [1]. He addressed the need to hold social media platforms accountable for their impact on children and called for stronger privacy protections and mental health services [2]. Biden also announced measures against Russia, including preventing its central bank from defending the Ruble and targeting Russian oligarchs' assets, as part of efforts to weaken Russia's economy and military [3]. Additionally, he reaffirmed the commitment to protect women's rights, particularly the right to choose as affirmed in Roe v. Wade [5]. Lastly, he advocated for funding the police with necessary resources and training to ensure community safety [6].
幻觉检测和事实一致性评分
Vectara 创建了 HHEM - 一个开源模型，可用于评估 RAG 响应的事实一致性。
作为 Vectara RAG 的一部分，“事实一致性评分”（或 FCS），它是开源 HHEM 的改进版本，通过 API 提供。该评分会自动包含在 RAG 流水线的输出中。
resp = rag.invoke(query_str)
print(resp["answer"])
print(f"Vectara FCS = {resp['fcs']}")
President Biden discussed several key topics in his recent statements. He emphasized the importance of keeping schools open and noted that with a high vaccination rate and reduced hospitalizations, most Americans can safely return to normal activities without masks [1]. He addressed the need to hold social media platforms accountable for their impact on children and called for stronger privacy protections and mental health services [2]. Biden also announced measures against Russian oligarchs, including closing American airspace to Russian flights and targeting their assets, as part of efforts to weaken Russia's economy [3], [7]. Additionally, he reaffirmed the need to protect women's rights, particularly the right to choose as affirmed in Roe v. Wade [5].
Vectara FCS = 0.61621094
Vectara 作为 LangChain 检索器
Vectara 组件也可以仅用作检索器。
在这种情况下，它的行为与任何其他 LangChain 检索器一样。此模式的主要用途是语义搜索，此时我们会禁用摘要功能：
config.generation = None
config.search.limit = 5
retriever = vectara.as_retriever(config=config)
retriever.invoke(query_str)
[Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='The U.S. Department of Justice is assembling a dedicated task force to go after the crimes of Russian oligarchs. We are joining with our European allies to find and seize your yachts your luxury apartments your private jets. We are coming for your ill-begotten gains. And tonight I am announcing that we will join our allies in closing off American air space to all Russian flights – further isolating Russia – and adding an additional squeeze –on their economy. The Ruble has lost 30% of its value.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='When they came home, many of the world’s fittest and best trained warriors were never the same. Dizziness. \n\nA cancer that would put them in a flag-draped coffin. I know. \n\nOne of those soldiers was my son Major Beau Biden. We don’t know for sure if a burn pit was the cause of his brain cancer, or the diseases of so many of our troops. But I’m committed to finding out everything we can.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='He rejected repeated efforts at diplomacy. He thought the West and NATO wouldn’t respond. And he thought he could divide us at home. We were ready. Here is what we did. We prepared extensively and carefully.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='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.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='Putin’s latest attack on Ukraine was premeditated and unprovoked. He rejected repeated efforts at diplomacy. He thought the West and NATO wouldn’t respond. And he thought he could divide us at home. We were ready. Here is what we did.')]
为了保持向后兼容性，您也可以通过检索器启用摘要功能，在这种情况下，摘要将作为额外的文档对象添加。
config.generation = GenerationConfig()
config.search.limit = 10
retriever = vectara.as_retriever(config=config)
retriever.invoke(query_str)
[Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='We won’t be able to compete for the jobs of the 21st Century if we don’t fix that. That’s why it was so important to pass the Bipartisan Infrastructure Law—the most sweeping investment to rebuild America in history. This was a bipartisan effort, and I want to thank the members of both parties who worked to make it happen. We’re done talking about infrastructure weeks. We’re going to have an infrastructure decade.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='The U.S. Department of Justice is assembling a dedicated task force to go after the crimes of Russian oligarchs. We are joining with our European allies to find and seize your yachts your luxury apartments your private jets. We are coming for your ill-begotten gains. And tonight I am announcing that we will join our allies in closing off American air space to all Russian flights – further isolating Russia – and adding an additional squeeze –on their economy. The Ruble has lost 30% of its value.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='When they came home, many of the world’s fittest and best trained warriors were never the same. Dizziness. \n\nA cancer that would put them in a flag-draped coffin. I know. \n\nOne of those soldiers was my son Major Beau Biden. We don’t know for sure if a burn pit was the cause of his brain cancer, or the diseases of so many of our troops. But I’m committed to finding out everything we can.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='Preventing Russia’s central bank from defending the Russian Ruble making Putin’s $630 Billion “war fund” worthless. We are choking off Russia’s access to technology that will sap its economic strength and weaken its military for years to come. Tonight I say to the Russian oligarchs and corrupt leaders who have bilked billions of dollars off this violent regime no more. The U.S. Department of Justice is assembling a dedicated task force to go after the crimes of Russian oligarchs. We are joining with our European allies to find and seize your yachts your luxury apartments your private jets.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='He rejected repeated efforts at diplomacy. He thought the West and NATO wouldn’t respond. And he thought he could divide us at home. We were ready. Here is what we did. We prepared extensively and carefully.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='It delivered immediate economic relief for tens of millions of Americans. Helped put food on their table, keep a roof over their heads, and cut the cost of health insurance. And as my Dad used to say, it gave people a little breathing room. And unlike the $2 Trillion tax cut passed in the previous administration that benefitted the top 1% of Americans, the American Rescue Plan helped working people—and left no one behind. Lots of jobs. \n\nIn fact—our economy created over 6.5 Million new jobs just last year, more jobs created in one year \nthan ever before in the history of America.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='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.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='All told, we created 369,000 new manufacturing jobs in America just last year. Powered by people I’ve met like JoJo Burgess, from generations of union steelworkers from Pittsburgh, who’s here with us tonight. As Ohio Senator Sherrod Brown says, “It’s time to bury the label “Rust Belt.” It’s time. \n\nBut with all the bright spots in our economy, record job growth and higher wages, too many families are struggling to keep up with the bills. Inflation is robbing them of the gains they might otherwise feel.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='Putin’s latest attack on Ukraine was premeditated and unprovoked. He rejected repeated efforts at diplomacy. He thought the West and NATO wouldn’t respond. And he thought he could divide us at home. We were ready. Here is what we did.'),
Document(metadata={'X-TIKA:Parsed-By': 'org.apache.tika.parser.csv.TextAndCSVParser', 'Content-Encoding': 'UTF-8', 'X-TIKA:detectedEncoding': 'UTF-8', 'X-TIKA:encodingDetector': 'UniversalEncodingDetector', 'Content-Type': 'text/plain; charset=UTF-8', 'source': 'text_file', 'framework': 'langchain'}, page_content='Danielle says Heath was a fighter to the very end. He didn’t know how to stop fighting, and neither did she. Through her pain she found purpose to demand we do better. Tonight, Danielle—we are. The VA is pioneering new ways of linking toxic exposures to diseases, already helping more veterans get benefits.'),
Document(metadata={'summary': True, 'fcs': (0.54785156,)}, page_content='President Biden spoke about several key issues. He emphasized the importance of the Bipartisan Infrastructure Law, calling it the most significant investment to rebuild America and highlighting it as a bipartisan effort [1]. He also announced measures against Russian oligarchs, including assembling a task force to seize their assets and closing American airspace to Russian flights, further isolating Russia economically [2]. Additionally, he expressed a commitment to investigating the health impacts of burn pits on military personnel, referencing his son, Major Beau Biden, who suffered from brain cancer [3].')]
使用Vectara进行高级LangChain查询预处理
Vectara的“RAG即服务”在创建问答或聊天机器人链时承担了大量的繁重工作。与LangChain的集成提供了使用额外功能的可能性，例如查询预处理，像SelfQueryRetriever或MultiQueryRetriever。让我们看看使用MultiQueryRetriever的一个示例。
由于 MQR 使用了大型语言模型 (LLM)，我们必须进行设置——在这里我们选择 ChatOpenAI：
from langchain.retrievers.multi_query import MultiQueryRetriever
from langchain_openai.chat_models import ChatOpenAI
llm = ChatOpenAI(temperature=0)
mqr = MultiQueryRetriever.from_llm(retriever=retriever, llm=llm)
def get_summary(documents):
return documents[-1].page_content
(mqr | get_summary).invoke(query_str)
API 参考：MultiQueryRetriever | ChatOpenAI
'The remarks made by Biden include his emphasis on the importance of the Bipartisan Infrastructure Law, which he describes as the most significant investment to rebuild America in history. He highlights the bipartisan effort involved in passing this law and expresses gratitude to members of both parties for their collaboration. Biden also mentions the transition from "infrastructure weeks" to an "infrastructure decade" [1]. Additionally, he shares a personal story about his father having to leave their home in Scranton, Pennsylvania, to find work, which influenced his decision to fight for the American Rescue Plan to help those in need [2].'