User`s guide

4 Arrays of LTI Models
4-10
Note:
• By convention, a single LTI model is treated as a 1-by-1 array of models.
For s ingle LTI models, size returns only the I/O dimensions
[Ny Nu].
• For LTI arrays, size always returns at least two array dimensions.
For example, the size of a 2-by-1 LTI array in
[Ny Nu 2 1]
• size ignores trailing singleton dimensions beyond the second array
dimension.
For example,
size returns [Ny Nu 2 3] for a 2-by-3-by-1-by-1 LTI array of
models with
Ny outputs and Nu inputs.
• You can use the syntax
size(sys,'order') to determine the number of
states inan LTI array,
sys. Amultidimensionalarray is returned ifsys is an
SS model s uch that the numbers of states in each model in
sys are not the
same.
The function
ndims returns the total number of dimensions in an LTI array:
• 2, for single LTI models
• 2+
p, for LTI arrays, where p (greater than 2) is the number of array
dimensions
Note that
ndims (sys) = length(size(sys))
To see how these work on the sample 2-by-3 LTI array m2d of two-output,
one-input models, type
load LTIexamples
s = size(m2d)
s =
2 1 2 3