Book Image

Getting Started with Google BERT

By : Sudharsan Ravichandiran
Book Image

Getting Started with Google BERT

By: Sudharsan Ravichandiran

Overview of this book

BERT (bidirectional encoder representations from transformer) has revolutionized the world of natural language processing (NLP) with promising results. This book is an introductory guide that will help you get to grips with Google's BERT architecture. With a detailed explanation of the transformer architecture, this book will help you understand how the transformer’s encoder and decoder work. You’ll explore the BERT architecture by learning how the BERT model is pre-trained and how to use pre-trained BERT for downstream tasks by fine-tuning it for NLP tasks such as sentiment analysis and text summarization with the Hugging Face transformers library. As you advance, you’ll learn about different variants of BERT such as ALBERT, RoBERTa, and ELECTRA, and look at SpanBERT, which is used for NLP tasks like question answering. You'll also cover simpler and faster BERT variants based on knowledge distillation such as DistilBERT and TinyBERT. The book takes you through MBERT, XLM, and XLM-R in detail and then introduces you to sentence-BERT, which is used for obtaining sentence representation. Finally, you'll discover domain-specific BERT models such as BioBERT and ClinicalBERT, and discover an interesting variant called VideoBERT. By the end of this BERT book, you’ll be well-versed with using BERT and its variants for performing practical NLP tasks.
Table of Contents (15 chapters)
1
Section 1 - Starting Off with BERT
5
Section 2 - Exploring BERT Variants
8
Section 3 - Applications of BERT

Chapter 1, A Primer on Transformers

  1. The steps involved in the self-attention mechanism are given here:
  • First, we compute the dot product between the query matrix and the key matrix and get the similarity scores.
  • Next, we divide by the square root of the dimension of the key vector .
  • Then, we apply the softmax function to normalize the scores and obtain the score matrix .
  • Finally, we compute the attention matrix by multiplying the score matrix with the value matrix .
  1. The self-attention mechanism is also called scaled dot product attention, since here we are computing the dot product (between the query and key vector) and scaling the values (with ).
  2. To create query, key, and value matrices, we introduce three new weight matrices called . We create the query , key , and value matrices, by multiplying the input matrix by ,, and , respectively.
  3. If we were to pass the preceding input matrix directly to the transformer, it would not understand the word order. So, instead of feeding...