function loop(A,xl,xr,delta)
% Find all eigenvalues between xl and xr for a symmetric matrix A
%               H. Hasegawa; July 2, 2006
z =[ 'alpha     count       eigenvalue      residual' ];
disp(z)
for i = xl:delta:xr
   y = gyaku1(A,i); 
   z = [sprintf('%5.2f',i) sprintf('%10.2f',y(1)) sprintf('%18.10f',y(2)) sprintf('%14.3e',y(3)) ];
   disp(z)
end