A transformer refers to two main things in the context of technology and machine learning: the transformer architecture and the transformer model.
Transformer Architecture:
The transformer architecture is a deep learning architecture introduced in the paper "Attention Is All You Need" by Vaswani et al. in 2017. It revolutionized various natural language processing (NLP) tasks by addressing some limitations of previous sequence-to-sequence models like recurrent neural networks (RNNs) and convolutional neural networks (CNNs). The transformer architecture is particularly known for its ability to handle long-range dependencies in sequences efficiently, which is crucial in tasks involving language understanding, generation, and translation.
Transformer Model:
The transformer model is built upon the concept of attention mechanisms, specifically self-attention, which allows the model to weigh the importance of different words in a sequence while processing each word. It consists of two main components: the encoder and the decoder.
Encoder:
The encoder takes the input sequence and processes it through multiple layers, each containing two main sub-layers: the multi-head self-attention mechanism and a feedforward neural network. The self-attention mechanism calculates the relevance of each word in the input sequence to every other word, capturing contextual information effectively. The feedforward neural network then processes the outputs of the self-attention mechanism to generate enriched representations of the input.
Decoder:
The decoder generates the output sequence, such as a translation or a response in a chatbot scenario. It also consists of multiple layers, but in addition to the self-attention and feedforward layers, it has a third sub-layer: the multi-head attention over the encoder's output. This allows the decoder to focus on relevant parts of the input while generating the output sequence.
The transformer architecture's key innovation lies in its ability to perform parallel processing of sequences due to its self-attention mechanism, which allows it to capture global dependencies without the sequential processing bottleneck of RNNs. This leads to faster training times and better performance on various NLP tasks.
In summary, the transformer architecture has become a foundational technology in natural language processing and has extended to other domains as well, including computer vision. Its core idea of self-attention and parallel processing has significantly improved the capabilities of neural networks to understand and generate sequences of data.