1-dimensional matrix: vector, such as [1,2,3]

2-dimensional matrix: The most common matrix, such as [11,12,13],[21,22,23],[31,32,33]]

3-dimensional matrix:such as [[[111,112,113],[121,122,123],[131,132,133]],[[211,212,213],[221,222,223],[231,232,233]]]

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In some matrix functions, dimensionalitylayer n is usually used to describe the calculated object. For example, in the 2-dimensional matrix [[11,12,13],[21,22,23],[31,32,33]], the dimensional member of the first layer refers to three vector members [11,12,13],[21,22,23],[31,32,33]. The second dimension refers to the members of each vector such as the first vector containing 11, 12, and 13

Similarly in the 3-dimensional matrix[[[111,112,113],[121,122,123],[131,132,133]],[[211,212,213],[221,222,223],[231,232,233]]] ,n=1, refers to two 3 * 3 matrix

n=2, refers to the vector members of each matrix

n=3, refers to the members of each vector