%  Example 5.6.  Determine robust stability.
clear
%  Define the nominal plant transfer function.
nup=10;
dep=[1 -1];
%  Define the controller.
nuk=1/2;
dek=1;
%  Generate the closed loop transfer function from wd to yd.
[nu,de]=feedback(nuk,dek,nup,dep);
nu=-nu;
%  Compute the infinity-norm.
Mydwd=nd2sys(nu,de);
temp=hinfnorm(Mydwd);
%  The infinity-norm is given as the average of the bounds.
HinfNorm=(temp(1)+temp(2))/2
