function rtheta(n)
%n = 6; 
m=2;
T = chaingraph(n);
global RR HH
%RR = []; HH=[];
while 1
  for i=1:m
    for j=1:m
      psi(i,j) = randinseg(1,5);
    end
  end
  P = treefillprob(m,n,T,psi);
  [b,A,C,dd] = is_markov(P,m,n); th = strict(A);
  %[hh,Ht,H] = gethhn(P,m,n); th = H;
  R = max(psi(:))/min(psi(:));
  RR(end+1) = R;
  HH(end+1) = th;
  hold off
  plot(RR,HH,'ob');
  %alf = max( log(1-HH)./(1-RR) );
  hold on
  %plot(RR,(1-exp(alf*(1-RR))),'.r');
  plot(RR,(RR-1)./(RR+1),'.r')
  drawnow
  %fprintf('n = %d alf = %1.9f \n',n,alf);
end
return