The term "transformer" can refer to different things depending on the context, but I'll assume you're asking about the transformer architecture used in deep learning, particularly the one popularized by the "Attention Is All You Need" paper by Vaswani et al. in 2017. The transformer is a type of neural network architecture primarily used for natural language processing tasks, such as machine translation, language modeling, and text generation. It has since become a fundamental building block for various other tasks in the field of deep learning.
The function of a transformer is to enable effective and efficient modeling of long-range dependencies in sequences of data. It addresses some limitations of previous sequence-to-sequence models, like recurrent neural networks (RNNs) and long short-term memory (LSTM) networks, which struggle with handling long-range dependencies due to their sequential nature.
The key innovation in the transformer is the self-attention mechanism, also known as scaled dot-product attention. This mechanism allows the model to weigh the importance of different words (or tokens) in the input sequence when processing each word, giving it the ability to focus on relevant parts of the input when generating the output.
The transformer architecture consists of an encoder-decoder structure:
Encoder: The encoder takes the input sequence (e.g., a sentence in a source language for machine translation) and processes it in parallel, calculating self-attention scores to learn the contextual representations of each word in the sequence.
Decoder: The decoder takes the encoder's contextual representations and generates the output sequence (e.g., a translated sentence in a target language). The decoder also uses self-attention to ensure that each word in the output sequence is generated with the proper context from both the input sequence and the previously generated words.
The transformer architecture's ability to handle long-range dependencies in parallel makes it more computationally efficient than RNNs and LSTMs, which process sequences sequentially. This efficiency has made transformers highly successful in various natural language processing tasks and has led to the development of larger and more powerful models, such as BERT (Bidirectional Encoder Representations from Transformers) and GPT (Generative Pre-trained Transformer). These models have achieved state-of-the-art results on a wide range of language understanding and generation tasks.