MATLAB POLYSPACE RELEASE NOTES Manual do Utilizador descarregar pdf (Página 147)

Other Data Structures

In this section.. .

“Multidimensional A rrays” on page 4-9

“Cell Arrays” on page 4-11

“Characters and Text” on page 4-13

“Structures” on page 4-16

Multidimensional Arrays

Multidimensional arrays in MATLAB are arrays with more than two

subscripts. One way of creating a multidimensional array is by calling

zeros,

ones, rand,orrandn with more than two arguments. For example,

R = randn(3,4,5);

creates a 3-by-4-by-5 array with a total of 3 *4* 5 = 60 normally distributed

random elements.

A three-dimensional array might represent three-dimensional phys ical data,

say the temperature in a room, sampled on a rectangular grid. Or it might

represent a sequence of m atrices, A

(k)

, or sam ples of a time-dependent m atrix ,

A(t). In these latter cases, the (i, j)th element of the kth matrix, or the t

matrix, is denoted by

A(i,j,k).

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

p = perms(1:4);

generates the 4! = 24 permutations of 1:4.Thekth perm utation is the row

vector

p(k,:).Then

A = magic(4);

M = zeros(4,4,24);

for k = 1:24

4-9

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MATLAB POLYSPACE RELEASE NOTES Manual do Utilizador Página 147