h_cl — closed loop matrix
[Acl]=h_cl(P,r,K) [Acl]=h_cl(P22,K)
linear system (syslin list), augmented plant or nominal plant respectively
1x2 row vector, dimensions of 2,2 part of P (r=[rows,cols]=size(P22))
linear system (syslin list), controller
real square matrix
Given the standard plant P (with r=size(P22)) and the controller
K, this function returns the closed loop matrix Acl.
The poles of Acl must be stable for the internal stability
of the closed loop system.
Acl is the A-matrix of the linear system [I -P22;-K I]^-1 i.e.
the A-matrix of lft(P,r,K)