size

Arguments

x

a 2-D or n-D array of any type or a list

sz

1 by ndims(x) integer vector.

sel

a positive scalar with integer value or one of the character strings 'r', 'c' or '*'

n1, n2, ...

numbers with integer values

n

a number with integer value

Description

Applied to :

an array or n-D array (constant, polynomial, string, boolean, rational)

• sz = size(x) returns a 1-by-ndims(x) vector. Each entry gives the corresponding dimension value.
• [n1, n2, ...] = size(x), the function returns in each argument the corresponding dimension value.
• The syntax n = size(x, sel) may be used to specify what dimension to get:
  • Set sel to 1 or 'r' to get the number of rows.
  • Set sel to 2 or 'c' to get the number of columns.
  • Set sel to m, where m is a positive integer to get the mth dimension. If m is greater than ndims(x), then size(x,m) returns 1.
  • Set sel to '*' to get the product of the dimensions.

Applied to:

a list; it returns the number of elements. In this case only y = size(x) syntax can be used.

Applied to:

a linear system; y= size(x) returns in y the (row) vector [number of outputs, number of inputs] i.e. the dimension of the corresponding transfer matrix. The syntax [nr, nc] = size(x) is also valid (with (nr, nc) = (y(1), y(2))). If x is a linear system in state-space form, then [nr, nc, nx] = size(x) returns in addition the dimension nx of matrix x.

Examples

[n, m] = size(rand(3, 2))
[n, m] = size(['a', 'b'; 'c', 'd'])

x = ssrand(3, 2, 4);
[ny, nu] = size(x)
[ny, nu] = size(ss2tf(x))
[ny, nu, nx] = size(x)

// Returns the number of rows
n = size(rand(3, 2), "r")
// Returns the number of columns
m = size(rand(3, 2), "c")
// Returns the product of the dimensions
nm = size(rand(3, 2), "*")

See also

• length — length of object
• ndims — number of dimensions of an array
• syslin — linear system definition