LangChain
欢迎使用Pinecone和LangChain的集成指南。本文档涵盖了将高性能向量数据库Pinecone与基于大型语言模型（LLMs）构建应用程序的框架LangChain集成的步骤。
Pinecone使开发人员能够基于向量相似性搜索构建可扩展的实时推荐和搜索系统。另一方面，LangChain提供了管理和优化应用程序中语言模型使用的模块。其核心理念是促进数据感知应用程序，其中语言模型与其他数据源及其环境交互。
通过将Pinecone与LangChain集成，您可以开发利用两个平台的优势的复杂应用程序。这可让我们为LLMs添加"长期记忆"，从而大大增强自主代理、聊天机器人和问答系统等的能力。
自然有许多使用这两个工具的方式。我们已经在许多示例和学习材料中详细介绍了这个过程，包括：
本指南的其余部分将向您展示如何使用Pinecone和LangChain进行简单的检索增强示例。
LangChain中的检索增强
LLMs存在数据新鲜度问题。世界上最强大的LLMs，如GPT-4，对最近的世界事件一无所知。
LLMs的世界被冻结在时间中。他们的世界存在于他们的训练数据所在的世界的静态快照中。
解决这个问题的一个方法是检索增强。其思想是我们从外部知识库中检索相关信息，并将这些信息提供给我们的LLM。在这个笔记本中，我们将学习如何做到这一点。
首先，我们必须安装我们将在本笔记本中使用的先决条件库。
Python
!pip install -qU langchain==0.0.162 openai tiktoken "pinecone-client[grpc]" datasets apache_beam mwparserfromhell
🚨 注意：上述“pip install”命令是为Jupyter Notebooks格式化的。如果在其他地方运行，则可能需要删除！。
建立知识库
Python
from datasets import load_dataset
data = load_dataset("wikipedia", "20220301.simple", split='train[:10000]')
data
Dataset({
features: ['id', 'url', 'title', 'text'],
num_rows: 10000
})
Python
data[6]
{'id': '13',
'url': 'https://simple.wikipedia.org/wiki/Alan%20Turing',
'title': 'Alan Turing',
'text': 'Alan Mathison Turing OBE FRS (London, 23 June 1912 – Wilmslow, Cheshire, 7 June 1954) was an English mathematician and computer scientist. He was born in Maida Vale, London. Early life and family \nAlan Turing was born in Maida Vale, London on 23 June 1912. His father was part of a family of merchants from Scotland. His mother, Ethel Sara, was the daughter of an engineer. Education \nTuring went to St. Michael\'s, a school at 20 Charles Road, St Leonards-on-sea, when he was five years old.\n"This is only a foretaste of what is to come, and only the shadow of what is going to be.” – Alan Turing. The Stoney family were once prominent landlords, here in North Tipperary. His mother Ethel Sara Stoney (1881–1976) was daughter of Edward Waller Stoney (Borrisokane, North Tipperary) and Sarah Crawford (Cartron Abbey, Co. Longford); Protestant Anglo-Irish gentry. Educated in Dublin at Alexandra School and College; on October 1st 1907 she married Julius Mathison Turing, latter son of Reverend John Robert Turing and Fanny Boyd, in Dublin. Born on June 23rd 1912, Alan Turing would go on to be regarded as one of the greatest figures of the twentieth century. A brilliant mathematician and cryptographer Alan was to become the founder of modern-day computer science and artificial intelligence; designing a machine at Bletchley Park to break secret Enigma encrypted messages used by the Nazi German war machine to protect sensitive commercial, diplomatic and military communications during World War 2. Thus, Turing made the single biggest contribution to the Allied victory in the war against Nazi Germany, possibly saving the lives of an estimated 2 million people, through his effort in shortening World War II. In 2013, almost 60 years later, Turing received a posthumous Royal Pardon from Queen Elizabeth II. Today, the “Turing law” grants an automatic pardon to men who died before the law came into force, making it possible for living convicted gay men to seek pardons for offences now no longer on the statute book. Alas, Turing accidentally or otherwise lost his life in 1954, having been subjected by a British court to chemical castration, thus avoiding a custodial sentence. He is known to have ended his life at the age of 41 years, by eating an apple laced with cyanide. Career \nTuring was one of the people who worked on the first computers. He created the theoretical Turing machine in 1936. The machine was imaginary, but it included the idea of a computer program. Turing was interested in artificial intelligence. He proposed the Turing test, to say when a machine could be called "intelligent". A computer could be said to "think" if a human talking with it could not tell it was a machine. During World War II, Turing worked with others to break German ciphers (secret messages). He worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain\'s codebreaking centre that produced Ultra intelligence.\nUsing cryptanalysis, he helped to break the codes of the Enigma machine. After that, he worked on other German codes. From 1945 to 1947, Turing worked on the design of the ACE (Automatic Computing Engine) at the National Physical Laboratory. He presented a paper on 19 February 1946. That paper was "the first detailed design of a stored-program computer". Although it was possible to build ACE, there were delays in starting the project. In late 1947 he returned to Cambridge for a sabbatical year. While he was at Cambridge, the Pilot ACE was built without him. It ran its first program on 10\xa0May 1950. Private life \nTuring was a homosexual man. In 1952, he admitted having had sex with a man in England. At that time, homosexual acts were illegal. Turing was convicted. He had to choose between going to jail and taking hormones to lower his sex drive. He decided to take the hormones. After his punishment, he became impotent. He also grew breasts. In May 2012, a private member\'s bill was put before the House of Lords to grant Turing a statutory pardon. In July 2013, the government supported it. A royal pardon was granted on 24 December 2013. Death \nIn 1954, Turing died from cyanide poisoning. The cyanide came from either an apple which was poisoned with cyanide, or from water that had cyanide in it. The reason for the confusion is that the police never tested the apple for cyanide. It is also suspected that he committed suicide. The treatment forced on him is now believed to be very wrong. It is against medical ethics and international laws of human rights. In August 2009, a petition asking the British Government to apologise to Turing for punishing him for being a homosexual was started. The petition received thousands of signatures. Prime Minister Gordon Brown acknowledged the petition. He called Turing\'s treatment "appalling". References Other websites \nJack Copeland 2012. Alan Turing: The codebreaker who saved \'millions of lives\'. BBC News / Technology English computer scientists\nEnglish LGBT people\nEnglish mathematicians\nGay men\nLGBT scientists\nScientists from London\nSuicides by poison\nSuicides in the United Kingdom\n1912 births\n1954 deaths\nOfficers of the Order of the British Empire'}
每个记录都包含大量文本。因此，我们的第一个任务是确定一个良好的预处理方法，将这些文章分成更“简洁”的块，以后在我们的Pinecone向量数据库中嵌入和存储。
为此，我们使用LangChain的RecursiveCharacterTextSplitter将文本分成指定最大长度的块。
Python
import tiktoken
tiktoken.encoding_for_model('gpt-3.5-turbo')
<Encoding 'cl100k_base'>
Python
import tiktoken
tokenizer = tiktoken.get_encoding('cl100k_base')
# create the length function
def tiktoken_len(text):
tokens = tokenizer.encode(
text,
disallowed_special=()
)
return len(tokens)
tiktoken_len("hello I am a chunk of text and using the tiktoken_len function "
"we can find the length of this chunk of text in tokens")
26
Python
from langchain.text_splitter import RecursiveCharacterTextSplitter
text_splitter = RecursiveCharacterTextSplitter(
chunk_size=400,
chunk_overlap=20,
length_function=tiktoken_len,
separators=[" ", "\n", " ", ""]
)
Python
chunks = text_splitter.split_text(data[6]['text'])[:3]
chunks
['Alan Mathison Turing OBE FRS (London, 23 June 1912 – Wilmslow, Cheshire, 7 June 1954) was an English mathematician and computer scientist. He was born in Maida Vale, London. Early life and family \nAlan Turing was born in Maida Vale, London on 23 June 1912. His father was part of a family of merchants from Scotland. His mother, Ethel Sara, was the daughter of an engineer. Education \nTuring went to St. Michael\'s, a school at 20 Charles Road, St Leonards-on-sea, when he was five years old.\n"This is only a foretaste of what is to come, and only the shadow of what is going to be.” – Alan Turing. The Stoney family were once prominent landlords, here in North Tipperary. His mother Ethel Sara Stoney (1881–1976) was daughter of Edward Waller Stoney (Borrisokane, North Tipperary) and Sarah Crawford (Cartron Abbey, Co. Longford); Protestant Anglo-Irish gentry. Educated in Dublin at Alexandra School and College; on October 1st 1907 she married Julius Mathison Turing, latter son of Reverend John Robert Turing and Fanny Boyd, in Dublin. Born on June 23rd 1912, Alan Turing would go on to be regarded as one of the greatest figures of the twentieth century.',
'A brilliant mathematician and cryptographer Alan was to become the founder of modern-day computer science and artificial intelligence; designing a machine at Bletchley Park to break secret Enigma encrypted messages used by the Nazi German war machine to protect sensitive commercial, diplomatic and military communications during World War 2. Thus, Turing made the single biggest contribution to the Allied victory in the war against Nazi Germany, possibly saving the lives of an estimated 2 million people, through his effort in shortening World War II. In 2013, almost 60 years later, Turing received a posthumous Royal Pardon from Queen Elizabeth II. Today, the “Turing law” grants an automatic pardon to men who died before the law came into force, making it possible for living convicted gay men to seek pardons for offences now no longer on the statute book. Alas, Turing accidentally or otherwise lost his life in 1954, having been subjected by a British court to chemical castration, thus avoiding a custodial sentence. He is known to have ended his life at the age of 41 years, by eating an apple laced with cyanide. Career \nTuring was one of the people who worked on the first computers. He created the theoretical Turing machine in 1936. The machine was imaginary, but it included the idea of a computer program. Turing was interested in artificial intelligence. He proposed the Turing test, to say when a machine could be called "intelligent". A computer could be said to "think" if a human talking with it could not tell it was a machine.',
'During World War II, Turing worked with others to break German ciphers (secret messages). He worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain\'s codebreaking centre that produced Ultra intelligence.\nUsing cryptanalysis, he helped to break the codes of the Enigma machine. After that, he worked on other German codes. From 1945 to 1947, Turing worked on the design of the ACE (Automatic Computing Engine) at the National Physical Laboratory. He presented a paper on 19 February 1946. That paper was "the first detailed design of a stored-program computer". Although it was possible to build ACE, there were delays in starting the project. In late 1947 he returned to Cambridge for a sabbatical year. While he was at Cambridge, the Pilot ACE was built without him. It ran its first program on 10\xa0May 1950. Private life \nTuring was a homosexual man. In 1952, he admitted having had sex with a man in England. At that time, homosexual acts were illegal. Turing was convicted. He had to choose between going to jail and taking hormones to lower his sex drive. He decided to take the hormones. After his punishment, he became impotent. He also grew breasts. In May 2012, a private member\'s bill was put before the House of Lords to grant Turing a statutory pardon. In July 2013, the government supported it. A royal pardon was granted on 24 December 2013. Death \nIn 1954, Turing died from cyanide poisoning. The cyanide came from either an apple which was poisoned with cyanide, or from water that had cyanide in it. The reason for the confusion is that the police never tested the apple for cyanide. It is also suspected that he committed suicide.']
Python
tiktoken_len(chunks[0]), tiktoken_len(chunks[1]), tiktoken_len(chunks[2])
(299, 323, 382)
使用text_splitter，我们可以得到更好尺寸的文本块。稍后在索引过程中将使用此功能。现在让我们看一下如何进行嵌入。
创建嵌入
使用LangChain的OpenAI嵌入功能构建嵌入非常简单。我们首先需要运行下一个单元格，以添加我们的OpenAI API密钥：
Python
from getpass import getpass
OPENAI_API_KEY = getpass("OpenAI API Key: ") # platform.openai.com
（请注意，OpenAI是一项付费服务，因此运行本笔记本的其余部分可能会产生一些小费用）
初始化API密钥后，我们可以像下面这样初始化text-embedding-ada-002嵌入模型：
Python
from langchain.embeddings.openai import OpenAIEmbeddings
model_name = 'text-embedding-ada-002'
embed = OpenAIEmbeddings(
model=model_name,
openai_api_key=OPENAI_API_KEY
)
Now we embed some text like so:
Python
texts = [
'this is the first chunk of text',
'then another second chunk of text is here'
]
res = embed.embed_documents(texts)
len(res), len(res[0])
(2, 1536)
从中可以得到两个（与我们的两个文本块对齐）1536维度的嵌入。
现在我们开始初始化Pinecone向量数据库。
向量数据库
要创建我们的向量数据库，我们首先需要从Pinecone获取免费API密钥。然后我们这样初始化：
Python
import pinecone
# find API key in console at app.pinecone.io
YOUR_API_KEY = getpass("Pinecone API Key: ")
# find ENV (cloud region) next to API key in console
YOUR_ENV = input("Pinecone environment: ")
index_name = 'langchain-retrieval-augmentation'
pinecone.init(
api_key=YOUR_API_KEY,
environment=YOUR_ENV
)
if index_name not in pinecone.list_indexes():
# we create a new index
pinecone.create_index(
name=index_name,
metric='cosine',
dimension=len(res[0]) # 1536 dim of text-embedding-ada-002
)
然后我们连接到新的索引：
Python
index = pinecone.GRPCIndex(index_name)
index.describe_index_stats()
{'dimension': 1536,
'index_fullness': 0.1,
'namespaces': {'': {'vector_count': 27437}},
'total_vector_count': 27437}
我们应该看到新的Pinecone索引具有total_vector_count为0，因为我们尚未添加任何向量。
索引
我们可以使用LangChain向量存储对象执行索引任务。但目前直接使用Pinecone Python客户端更快。我们将分批进行，每批100个或更多。
Python
from tqdm.auto import tqdm
from uuid import uuid4
batch_limit = 100
texts = []
metadatas = []
for i, record in enumerate(tqdm(data)):
# first get metadata fields for this record
metadata = {
'wiki-id': str(record['id']),
'source': record['url'],
'title': record['title']
}
# now we create chunks from the record text
record_texts = text_splitter.split_text(record['text'])
# create individual metadata dicts for each chunk
record_metadatas = [{
"chunk": j, "text": text, **metadata
} for j, text in enumerate(record_texts)]
# append these to current batches
texts.extend(record_texts)
metadatas.extend(record_metadatas)
# if we have reached the batch_limit we can add texts
if len(texts) >= batch_limit:
ids = [str(uuid4()) for _ in range(len(texts))]
embeds = embed.embed_documents(texts)
index.upsert(vectors=zip(ids, embeds, metadatas))
texts = []
metadatas = []
if len(texts) > 0:
ids = [str(uuid4()) for _ in range(len(texts))]
embeds = embed.embed_documents(texts)
index.upsert(vectors=zip(ids, embeds, metadatas))
0%| | 0/10000 [00:00<?, ?it/s]
我们现在已经索引了所有内容。我们可以这样检查索引中向量的数量：
Python
index.describe_index_stats()
{'dimension': 1536,
'index_fullness': 0.1,
'namespaces': {'': {'vector_count': 27437}},
'total_vector_count': 27437}
创建向量存储并查询
现在我们已经构建了索引，可以切换到 LangChain。我们首先使用刚刚构建的索引初始化一个向量存储。我们可以这样做：
Python
from langchain.vectorstores import Pinecone
text_field = "text"
# switch back to normal index for langchain
index = pinecone.Index(index_name)
vectorstore = Pinecone(
index, embed.embed_query, text_field
)
Python
query = "who was Benito Mussolini?"
vectorstore.similarity_search(
query, # our search query
k=3 # return 3 most relevant docs
)
[Document(page_content='Benito Amilcare Andrea Mussolini KSMOM GCTE (29 July 1883 – 28 April 1945) was an Italian politician and journalist. He was also the Prime Minister of Italy from 1922 until 1943. He was the leader of the National Fascist Party. Biography Early life\nBenito Mussolini was named after Benito Juarez, a Mexican opponent of the political power of the Roman Catholic Church, by his anticlerical (a person who opposes the political interference of the Roman Catholic Church in secular affairs) father. Mussolini\'s father was a blacksmith. Before being involved in politics, Mussolini was a newspaper editor (where he learned all his propaganda skills) and elementary school teacher. At first, Mussolini was a socialist, but when he wanted Italy to join the First World War, he was thrown out of the socialist party. He \'invented\' a new ideology, Fascism, much out of Nationalist\xa0and Conservative views. Rise to power and becoming dictator\nIn 1922, he took power by having a large group of men, "Black Shirts," march on Rome and threaten to take over the government. King Vittorio Emanuele III gave in, allowed him to form a government, and made him prime minister. In the following five years, he gained power, and in 1927 created the OVRA, his personal secret police force. Using the agency to arrest, scare, or murder people against his regime, Mussolini was dictator\xa0of Italy by the end of 1927. Only the King and his own Fascist party could challenge his power.', lookup_str='', metadata={'chunk': 0.0, 'source': 'https://simple.wikipedia.org/wiki/Benito%20Mussolini', 'title': 'Benito Mussolini', 'wiki-id': '6754'}, lookup_index=0),
Document(page_content='Fascism as practiced by Mussolini\nMussolini\'s form of Fascism, "Italian Fascism"- unlike Nazism, the racist ideology that Adolf Hitler followed- was different and less destructive than Hitler\'s. Although a believer in the superiority of the Italian nation and national unity, Mussolini, unlike Hitler, is quoted "Race? It is a feeling, not a reality. Nothing will ever make me believe that biologically pure races can be shown to exist today". Mussolini wanted Italy to become a new Roman Empire. In 1923, he attacked the island of Corfu, and in 1924, he occupied the city state of Fiume. In 1935, he attacked the African country Abyssinia (now called Ethiopia). His forces occupied it in 1936. Italy was thrown out of the League of Nations because of this aggression. In 1939, he occupied the country Albania. In 1936, Mussolini signed an alliance with Adolf Hitler, the dictator of Germany. Fall from power and death\nIn 1940, he sent Italy into the Second World War on the side of the Axis countries. Mussolini attacked Greece, but he failed to conquer it. In 1943, the Allies landed in Southern Italy. The Fascist party and King Vittorio Emanuel III deposed Mussolini and put him in jail, but he was set free by the Germans, who made him ruler of the Italian Social Republic puppet state which was in a small part of Central Italy. When the war was almost over, Mussolini tried to escape to Switzerland with his mistress, Clara Petacci, but they were both captured and shot by partisans. Mussolini\'s dead body was hanged upside-down, together with his mistress and some of Mussolini\'s helpers, on a pole at a gas station in the village of Millan, which is near the border between Italy and Switzerland.', lookup_str='', metadata={'chunk': 1.0, 'source': 'https://simple.wikipedia.org/wiki/Benito%20Mussolini', 'title': 'Benito Mussolini', 'wiki-id': '6754'}, lookup_index=0),
Document(page_content='Fascist Italy \nIn 1922, a new Italian government started. It was ruled by Benito Mussolini, the leader of Fascism in Italy. He became head of government and dictator, calling himself "Il Duce" (which means "leader" in Italian). He became friends with German dictator Adolf Hitler. Germany, Japan, and Italy became the Axis Powers. In 1940, they entered World War II together against France, Great Britain, and later the Soviet Union. During the war, Italy controlled most of the Mediterranean Sea. On July 25, 1943, Mussolini was removed by the Great Council of Fascism. On September 8, 1943, Badoglio said that the war as an ally of Germany was ended. Italy started fighting as an ally of France and the UK, but Italian soldiers did not know whom to shoot. In Northern Italy, a movement called Resistenza started to fight against the German invaders. On April 25, 1945, much of Italy became free, while Mussolini tried to make a small Northern Italian fascist state called the Republic of Salò. The fascist state failed and Mussolini tried to flee to Switzerland and escape to Francoist Spain, but he was captured by Italian partisans. On 28 April 1945 Mussolini was executed by a partisan. After World War Two The state became a republic on June 2, 1946. For the first time, women were able to vote. Italian people ended the Savoia dynasty and adopted a republic government. In February 1947, Italy signed a peace treaty with the Allies. They lost all the colonies and some territorial areas (Istria and parts of Dalmatia). Since then Italy has joined NATO and the European Community (as a founding member). It is one of the seven biggest industrial economies in the world. Transportation The railway network in Italy totals . It is the 17th longest in the world. High speed trains include ETR-class trains which travel at .', lookup_str='', metadata={'chunk': 5.0, 'source': 'https://simple.wikipedia.org/wiki/Italy', 'title': 'Italy', 'wiki-id': '363'}, lookup_index=0)]
所有这些都是好的、相关的结果。但我们能做什么呢？有很多任务，其中最有趣的之一（也是 LangChain 支持最好的之一）叫做 “生成式问答” 或 GQA。
生成式问答
在GQA中，我们将查询作为要由LLM回答的问题，但LLM必须根据从“vectorstore”返回的信息来回答问题。
为了做到这一点，我们要像这样初始化一个RetrievalQA对象：
Python
from langchain.chat_models import ChatOpenAI
from langchain.chains import RetrievalQA
# completion llm
llm = ChatOpenAI(
openai_api_key=OPENAI_API_KEY,
model_name='gpt-3.5-turbo',
temperature=0.0
)
qa = RetrievalQA.from_chain_type(
llm=llm,
chain_type="stuff",
retriever=vectorstore.as_retriever()
)
Python
qa.run(query)
'Benito Mussolini was an Italian politician and journalist who served as the Prime Minister of Italy from 1922 until 1943. He was the leader of the National Fascist Party and invented the ideology of Fascism. Mussolini was a dictator of Italy by the end of 1927, and his form of Fascism, "Italian Fascism," was different and less destructive than Hitler\'s Nazism. Mussolini wanted Italy to become a new Roman Empire and attacked several countries, including Abyssinia (now called Ethiopia) and Greece. He was removed from power in 1943 and was executed by Italian partisans in 1945.'
我们还可以包括LLM用来回答问题的信息来源。我们可以使用稍微不同的RetrievalQA版本——RetrievalQAWithSourcesChain来做到这一点：
Python
from langchain.chains import RetrievalQAWithSourcesChain
qa_with_sources = RetrievalQAWithSourcesChain.from_chain_type(
llm=llm,
chain_type="stuff",
retriever=vectorstore.as_retriever()
)
Python
qa_with_sources(query)
{'question': 'who was Benito Mussolini?',
'answer': 'Benito Mussolini was an Italian politician and journalist who was the Prime Minister of Italy from 1922 until 1943. He was the leader of the National Fascist Party and invented the ideology of Fascism. He became dictator of Italy by the end of 1927 and was friends with German dictator Adolf Hitler. Mussolini attacked Greece and failed to conquer it. He was removed by the Great Council of Fascism in 1943 and was executed by a partisan on April 28, 1945. After the war, several Neo-Fascist movements have had success in Italy, the most important being the Movimento Sociale Italiano. His granddaughter Alessandra Mussolini has outspoken views similar to Fascism. \n',
'sources': 'https://simple.wikipedia.org/wiki/Benito%20Mussolini, https://simple.wikipedia.org/wiki/Fascism'}
现在我们回答被问到的问题，并返回 LLM 正在使用的信息源。
更新于大约 16 小时前