Other Data Structures
This section introduces you to some other data structures in MATLAB, including
Multidimensional arrays in MATLAB are arrays with more than two subscripts. They can be created by calling
randn with more than two arguments. For example,
creates a 3-by-4-by-5 array with a total of 3x4x5 = 60 normally distributed random elements.
A three-dimensional array might represent three-dimensional physical data, say the temperature in a room, sampled on a rectangular grid. Or, it might represent a sequence of matrices, A(k), or samples of a time-dependent matrix, A(t). In these latter cases, the (i, j)th element of the kth matrix, or the tkth matrix, is denoted by
MATLAB and Dürer's versions of the magic square of order 4 differ by an interchange of two columns. Many different magic squares can be generated by interchanging columns. The statement
generates the 4! = 24 permutations of
kth permutation is the row vector,
stores the sequence of 24 magic squares in a three-dimensional array,
M. The size of
It turns out that the third matrix in the sequence is Dürer's.
computes sums by varying the
dth subscript. So
is a 1-by-4-by-24 array containing 24 copies of the row vector
is a 4-by-1-by-24 array containing 24 copies of the column vector
adds the 24 matrices in the sequence. The result has size 4-by-4-by-1, so it looks like a 4-by-4 array.