维克塔拉
Vectara 是值得信赖的 AI Assistant 和 Agent 平台，专注于为任务关键型应用程序做好企业准备。 Vectara 无服务器 RAG-as-a-service 在易于使用的 API 后面提供 RAG 的所有组件，包括：
- 一种从文件中提取文本的方法（PDF、PPT、DOCX 等）
- 基于 ML 的分块，提供最先进的性能。
- Boomerang 嵌入模型。
- 它自己的内部向量数据库，其中存储了文本块和嵌入向量。
- 一种查询服务，可自动将查询编码为嵌入内容，并检索最相关的文本段，包括对混合搜索的支持以及多个重新排名选项，如多语言相关性重新排名程序、MMR、UDF 重新排序程序。
- 用于根据检索到的文档（上下文）创建生成摘要的 LLM，包括引文。
有关更多信息，请访问：
此笔记本展示了在将 Vectara 用作 Vector Store（无摘要）时如何使用基本检索功能，包括：similarity_search和similarity_search_with_score以及使用 LangChainas_retriever功能性。
设置
要使用VectaraVectorStore您首先需要安装 Partner Package。
!uv pip install -U pip && uv pip install -qU langchain-vectara
开始
要开始使用，请使用以下步骤：
- 如果您还没有，请注册您的 Vectara 免费试用版。
- 在您的帐户中，您可以创建一个或多个语料库。每个语料库都表示一个区域，该区域在从输入文档摄取时存储文本数据。要创建语料库，请使用 “Create Corpus” 按钮。然后，您为语料库提供名称以及描述。（可选）您可以定义筛选属性并应用一些高级选项。如果你点击你创建的语料库，你可以在顶部看到它的名称和语料库 ID。
- 接下来，您需要创建 API 密钥来访问语料库。单击语料库中的 “Access Control” 选项卡，然后单击 “Create API Key” 按钮。为您的密钥命名，然后选择是要对密钥进行 query-only 还是 query+index。单击 “Create”（创建），您现在拥有一个有效的 API 密钥。对此密钥保密。
要将 LangChain 与 Vectara 一起使用，您需要具有以下两个值：corpus_key和api_key.
您可以提供VECTARA_API_KEY以两种方式发送到 LangChain：
-
在您的环境中包括这两个变量：
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
Vectaravectorstore 构造函数：
vectara = Vectara(
vectara_api_key=vectara_api_key
)
在此笔记本中，我们假设它们在环境中提供。
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，我们将国情咨文加载到 Vectara 中。
请注意，我们使用不需要任何本地处理或分块的 add_files 接口 - Vectara 接收文件内容并执行所有必要的预处理、分块并将文件嵌入到其知识存储中。
在这种情况下，它使用 .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（检索增强一代）
现在，我们创建一个VectaraQueryConfigobject 来控制检索和摘要选项：
- 我们启用摘要，指定我们希望 LLM 选择前 7 个匹配的块并用英语回复
使用这个配置，让我们创建一个 LangChainRunnable对象，该对象使用as_rag方法：
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]."
我们也可以使用像这样的 streaming 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，这是一个开源模型，可用于评估 RAG 响应的事实一致性。
作为 Vectara RAG 的一部分，“事实一致性分数”（或 FCS）是通过 API 提供的，它是开源 HHEM 的改进版本。这会自动包含在 RAG 管道的输出中
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 as a langchain retreiver
Vectara 组件也可以用作检索器。
在这种情况下，它的行为与任何其他 LangChain 检索器一样。这种模式的主要用途是语义搜索，在这种情况下我们禁用 summarization：
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.')]
为了向后兼容，您还可以使用检索器启用摘要，在这种情况下，摘要将添加为额外的 Document 对象：
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方面承担了大量繁重的工作。与 LangChain 的集成提供了使用其他功能的选项，例如查询预处理，例如SelfQueryRetriever或MultiQueryRetriever.让我们看一个使用 MultiQueryRetriever 的示例。
由于 MQR 使用 LLM，因此我们必须对其进行设置 - 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 | 聊天OpenAI
'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].'