在本文中，我们将介绍如何使用Hugging Face的大型语言模型（LLM）构建一些常见的应用，包括摘要（Summarization）、情感分析（Sentiment analysis）、翻译（Translation）、零样本分类（Zero-shot classification）和少样本学习（Few-shot learning）。我们将探索现有的开源和专有模型，展示如何直接应用于各种应用场景。同时，我们还将介绍简单的提示工程（prompt engineering），以及如何使用Hugging Face的API配置LLM管道。

学习目标：

• 使用各种现有模型构建常见应用。

• 理解基本的提示工程。

• 了解LLM推理中的搜索和采样方法。

• 熟悉Hugging Face的主要抽象概念：数据集、管道、分词器和模型。

环境安装

常见的大预言模型应用

本节旨在让您对几种常见的LLM应用有所了解，并展示使用LLM的入门方法的简易性。

在浏览示例时，请注意所使用的数据集、模型、API和选项。这些简单的示例可作为构建自己应用程序的起点。

摘要(Summarization)

摘要可以分为两种形式：

1. 抽取式摘要（extractive）：从文本中选择代表性的摘录作为摘要。

2. 生成式摘要（abstractive）：通过生成新的文本来形成摘要。

在本文中，我们将使用生成式摘要模型。

背景阅读：Hugging Face的摘要任务页面列出了支持摘要的模型架构。摘要章节提供了详细的操作指南。

在本节中，我们将使用以下内容：

• 数据集：xsum数据集，该数据集提供了一系列BBC新闻文章和相应的摘要。

• 模型：t5-small模型，该模型具有6000万个参数（对于PyTorch而言是242MB）。T5是由Google创建的编码器-解码器模型，支持多个任务，包括摘要、翻译、问答和文本分类。有关更多详细信息，请参阅Google的博客文章、GitHub上的代码或研究论文。

数据集加载

`xsum_dataset = load_dataset(
       "xsum", version="1.2.0", cache_dir="/root/home/LLMs/week1"   
)  # Note: We specify cache_dir to use predownloaded data.   
xsum_dataset  # The printed representation of this object shows the `num_rows` of each dataset split.      

# 输出   
DatasetDict({    
    train: Dataset({           
        features: ['document', 'summary', 'id'],           
        num_rows: 204045       
    })       
    validation: Dataset({      
        features: ['document', 'summary', 'id'],           
        num_rows: 11332       
    })       
    test: Dataset({      
        features: ['document', 'summary', 'id'],           
        num_rows: 11334       
    })   
})   `

该数据集提供了三列：

• document：包含BBC文章的文本内容。

• summary：一个“ground-truth”摘要。请注意，“ground-truth”摘要是主观的，可能与您所写的摘要不同。这是一个很好的例子，说明许多LLM应用程序没有明显的“正确”答案。

• id：文章的唯一标识符。

xsum_sample = xsum_dataset["train"].select(range(10))   
display(xsum_sample.to_pandas())   

接下来，我们将使用Hugging Face的pipeline工具加载一个预训练模型。在LLM（Language Model）pipeline的构造函数中，我们需要指定以下参数：

• task：第一个参数用于指定主要任务。您可以参考Hugging Face的task文档获取更多信息。

• model：这是从Hugging Face Hub加载的预训练模型的名称。

• min_length、max_length：我们可以设置生成的摘要的最小和最大标记长度范围。

• truncation：一些输入文章可能过长，超出了LLM处理的限制。大多数LLM模型对输入序列的长度有固定的限制。通过设置此选项，我们可以告诉pipeline在需要时对输入进行截断。

# Apply to 1 article   
summarizer(xsum_sample["document"][0])      

# Apply to a batch of articles   
results = summarizer(xsum_sample["document"])      

# Display the generated summary side-by-side with the reference summary and original document.   
# We use Pandas to join the inputs and outputs together in a nice format.   
import pandas as pd       

display(    
    pd.DataFrame.from_dict(results)       
    .rename({"summary_text": "generated_summary"}, axis=1)       
    .join(pd.DataFrame.from_dict(xsum_sample))[       
        ["generated_summary", "summary", "document"]       
    ]   
)      

# 输出   
results   
[{'summary_text': 'the full cost of damage in Newton Stewart is still being assessed . many roads in peeblesshire remain badly affected by standing water . a flood alert remains in place across the'},  
 {'summary_text': 'a fire alarm went off at the Holiday Inn in Hope Street on Saturday . guests were asked to leave the hotel . the two buses were parked side-by-side in'},    
 {'summary_text': 'Sebastian Vettel will start third ahead of team-mate Kimi Raikkonen . stewards only handed Hamilton a reprimand after governing body said "n'},    
 {'summary_text': 'the 67-year-old is accused of committing the offences between March 1972 and October 1989 . he denies all the charges, including two counts of indecency'},    
 {'summary_text': 'a man receiving psychiatric treatment at the clinic threatened to shoot himself and others . the incident comes amid tension in Istanbul following several attacks on the reina nightclub .'},    
 {'summary_text': 'Gregor Townsend gave a debut to powerhouse wing Taqele Naiyaravoro . the dragons gave first starts of the season to wing a'},    
 {'summary_text': 'Veronica Vanessa Chango-Alverez, 31, was killed and another man injured in the crash . police want to trace Nathan Davis, 27, who has links to the Audi .'},    
 {'summary_text': 'the 25-year-old was hit by a motorbike during the Gent-Wevelgem race . he was riding for the Wanty-Gobert team and was taken'},    
 {'summary_text': 'gundogan will not be fit for the start of the premier league season at Brighton on 12 august . the 26-year-old says his recovery time is now being measured in "week'},    
 {'summary_text': 'the crash happened about 07:20 GMT at the junction of the A127 and Progress Road in leigh-on-Sea, Essex . the man, aged in his 20s'}]      

情感分析(Sentiment analysis)