Multi-head attention is an advanced mechanism in transformer architectures that allows the model to simultaneously attend to different representation subspaces of the input data. It consists of multiple attention heads, each computing its own attention scores and output. Formally, given input matrices Q (queries), K (keys), and V (values), the multi-head attention can be expressed as: MultiHead(Q, K, V) = Concat(head_1, ..., head_h)W^O, where head_i = Attention(QW_i^Q, KW_i^K, VW_i^V) for i = 1, ..., h. Here, W_i^Q, W_i^K, and W_i^V are learned projection matrices for each head, and W^O is a final linear transformation. This architecture allows the model to capture diverse contextual relationships by aggregating information from multiple perspectives, thus enhancing its representational capacity and improving performance on various tasks such as language modeling and image processing.
Multi-head attention is like having several people working together to solve a problem. Each person looks at the same information but focuses on different details. For example, if a group is analyzing a movie, one person might focus on the plot, another on the characters, and yet another on the cinematography. By combining their insights, they get a fuller understanding of the movie. In AI, multi-head attention helps models analyze data more effectively by allowing them to pay attention to various aspects at the same time, which is especially useful in tasks like translating languages or understanding text.