How do you calculate controllability matrix when A has non-numeric parameters?

The controllability matrix for a second-order system is Pc={B AB A^2] where A=[1 a;0 b] where a and b are non-numeric. How do you define A matrix in this case?

Answer 1

[Star Strider]

That is possible with the Symbolic Math Toolbox, although not with the Control System Toolbox:

syms A B a b 
B = sym('b',[2 2]);
A=[1 a;0 b];
Pc=[B A*B A^2];
NrUncontrollableStates = length(A) - rank(Pc)