Control System Toolbox™

size - Provide output/input/array dimensions of LTI model and number of frequencies of FRD model

Syntax

d = size(sys)
Ny = size(sys,1)
Nu = size(sys,2)
Sk = size(sys,2+k)
Nf = size(sys,'frequency')

Description

When invoked without output arguments, size(sys) returns a vector of the number of outputs and inputs for a single LTI model. The lengths of the array dimensions are also included in the response to size when sys is an LTI array. size is the overloaded version of the MATLAB function size for LTI objects.

d = size(sys) returns:

• The row vector d = [Ny Nu] for a single LTI model sys with Ny outputs and Nu inputs

• The row vector d = [Ny Nu S1 S2 ... Sp] for an S1-by-S2-by-...-by-Sp array of LTI models with Ny outputs and Nu inputs

Ny = size(sys,1) returns the number of outputs of sys.

Nu = size(sys,2) returns the number of inputs of sys.

Sk = size(sys,2+k) returns the length of the k-th array dimension when sys is an LTI array.

Nf = size(sys,'frequency') returns the number of frequencies when sys is an FRD. This is the same as the length of sys.frequency.

Example

Consider the random LTI array of state-space models

sys = rss(5,3,2,3);

Its dimensions are obtained by typing

size(sys)
3x1 array of state-space models
Each model has 3 outputs, 2 inputs, and 5 states.

See Also

isempty, issiso, ndims

sisotool

sminreal