%
% Example 6.4
%
eps=0.1;
A1=A(1:2,1:2);
A2=A(1:2,3:5);
A3=A(3:5,1:2)*eps;
A4=A(3:5,3:5)*eps;
B1=B(1:2,1:2);
B2=B(3:5,1:2)*eps;
C1=C(1:2,1:2);
C2=C(1:2,3:5);
As=A1-A2*inv(A4)*A3
Bs=B1-A2*inv(A4)*B2
Cs=C1-C2*inv(A4)*A3
Ds=-C2*inv(A4)*B2
end