User`s guide

size
11-207
11size
Purpose Provide the output/input/array dimensions of LTI models, the model order of
TF, SS, and ZPK models, and the number of frequencies of FRD models
Syntax size(sys)
d = size(sys)
Ny = size(sys,1)
Nu = size(sys,2)
Sk = size(sys,2+k)
Ns = size(sys,'order')
Nf = size(sys,'frequency')
Description When invoked without output a rguments, 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 responset o
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.
Ns = size(sys,'order') returns the model order of a TF, SS, or ZPK model.
This is the same as t he number of states for state-space models. When
sys is
an LTI array of SS models with differing numb ers of states in each model:
•
Ns is the multidimensional array of the orders of each of the models in the
LTI array.
• The dimensions of
Ns are given by the array dimensions of the LTI array sys.
Nf = size(sys,'frequency') returns the number of frequencies when sys is
an FRD. This is the same as the length of
sys.frequency.