function p7_1_1(a,e) %Compare the analytical bound on the Hinf norm with that %produced by MATLAB. if (e<=0) disp('epsilon must be positive!') return end A=-a; %Define canonical matrices B1=[0 1/e]; B2=1; C1=[0;1]; D11=[0 0;0 0]; D12=[e;0]; C2=1; D21=[1 0]; D22=0; B=[B1 B2]; C=[C1;C2] D=[D11 D12;D21 D22]; P=pck(A,B,C,D); [k,g,gfin]=hinfsyn(P,1,1,0,10*abs(a)*e+10,1e-8); %Compute minimal Hinf %norm in MATLAB if (a<=0) ganalytic=sqrt(2*((a*e)^2+1)+2*sqrt(((a*e)^2+1)^2-1)); else ganalytic=sqrt(2*((a*e)^2+1)-2*sqrt(((a*e)^2+1)^2-1)); end sprintf('Hinfsyn says that the maximal lower bound for gamma is %d.',gfin) sprintf('The analytical maximal lower bound on gamma is %d',ganalytic)