matrix multiplication is an efficient algorithm that can optimize some one-dimensional recursions to log(n), and can also find path plans, etc., so it is an extremely applicable algorithm. matrix is ​​one of the basic concepts in linear algebra. an m×n matrix is ​​an array of m×n numbers arranged in m rows and n columns. because it brings a lot of data together compactly, it can sometimes represent some complex models simply. matrix multiplication may seem strange, but it's actually very useful and widely used.