%% Create State-Space Model with Both Fixed and Tunable Parameters
% This example shows how to create a state-space genss model having both fixed and tunable parameters.
% A = \left[ {\begin{array}{*{20}{c}}
% 1&{a + b}\\
% 0&{ab}
% \end{array}} \right],\quad B = \left[ {\begin{array}{*{20}{c}}
% { - 3.0}\\
% {1.5}
% \end{array}} \right],\quad C = \left[ {\begin{array}{*{20}{c}}
% {0.3}&0
% \end{array}} \right],\quad D = 0,
% where a and b are tunable parameters, whose initial values are -1 and 3, respectively.
% Create the tunable parameters using realp.

a = realp('a',-1);
b = realp('b',3);

%
% Define a generalized matrix using algebraic expressions of a and b.

A = [1 a+b;0 a*b];

% A is a generalized matrix whose Blocks property contains a and b. The initial value of A is [1 2;0 -3], from the initial values of a and b.
%
% Create the fixed-value state-space matrices.

B = [-3.0;1.5];
C = [0.3 0];
D = 0;

%
% Use ss to create the state-space model.

sys = ss(A,B,C,D)

%
% sys is a generalized LTI model (genss) with tunable parameters a and b.
% Copyright 2012 The MathWorks, Inc.