User`s guide

Indexing Into LTI Arrays
4-23
Similarly, the commands
sys(:,:,3,2) = sys(:,:,4,1);
sys(1,2,3,2) = 0;
reassign the entire model in the (3,2) position ofthe LTI array sys and the (1,2)
subsystem of this model, respectively.
LTI Arrays of SS Models with Differing Numbers of States
You must use an entire LTI model for reassignment if you have an LTI array
sys of state-space models for which:
• The numbers of states in each model in sys is not constant.
• You want to change the dimensions of the
a, b,andcmatrices in one model
asyoureassignits
a,b,andcproperties.
For example, if
sys = ss(stack(1,tf(1,[1 2 1]),tf(1,[1 1])));
then the model sys(:,:,1) is of order 2, while sys(:,:,2) is of order 1. To
reassign the
a, b,andcproperties of sys(:,:,1) so that the state dimension of
the new model is not 2, you must make the entire model a ssignment at once.
You can do this as follows.
sys(:,:,1) = sys2
where sys2 represents an LTI model for which size(sys2,'order') is not 2.
Deleting Parts of an LTI Array
You can use indexing to delete any part of an LTI array by reassigning it to be
empty (
[]). For instance,
sys = rss(4,3,2,5,2);
sys(1,:) = [];
size(sys)
5x2 array of continuous-time state-space models
Each model has 2 outputs, 2 inputs, and 4 states.
deletes the first output channel from every model of this LTI a rray.