%% Examine and Change Properties of an Existing Model
% Load an existing state-space (ss) model.

load('PadeApproximation1.mat','sys')
sys

%
% The display shows that sys is a state-space model, and includes some of the property values of sys. To see all properties of sys, use the get command.

get(sys)

%
% Use dot notation to access the values of particular properties. For example, display the A matrix of sys.

Amat = sys.A

%
% Dot notation also lets you change the value of individual model properties.

sys.InputDelay = 4.2;
sys.InputName = 'thrust';
sys.OutputName = 'velocity';

%
% When you must change multiple property values at the same time to preserve the validity of the model, such as changing the dimensions of the state-space matrices, you can use the set command. For example, create a 1-state state-space model, and then replace the matrices with new values representing a 2-state model.

sys2 = rss(1);
Anew = [-2, 1; 0.5 0];
Bnew = [1; -1];
Cnew = [0, -0.4];
set(sys2,'A',Anew,'B',Bnew,'C',Cnew)
sys2

% Changing certain properties, such as Ts or TimeUnit, can cause undesirable changes in system behavior. See the property descriptions in the model reference pages for more information.
% Copyright 2012 The MathWorks, Inc.