c
c     Numerical Analysis:
c     The Mathematics of Scientific Computing
c     D.R. Kincaid & E.W. Cheney
c     Brooks/Cole Publ., 1990
c
c     Section 2.3
c
c     Example of unstable sequence
c
c
c     file: unstab1.f
c
      dimension x(0:15),y(0:15),e(0:15),f(0:15)
      double precision y
c
      print *
      print *,' Unstable sequence'
      print *,' Section 2.3, Kincaid-Cheney'
      print *
      print 4,'n','x(n)','true','error','rel. error'
c
      x(0) = 1.0
      x(1) = 1.0/3.0
      y(0) = 1.d0
      y(1) = 1.d0/3.d0
c
      do 2 n=1,14
         x(n+1) = (13./3.)*x(n) - (4./3.)*x(n-1)
         y(n+1) = (1.d0/3.d0)**(n+1)
 2    continue
c
      do 3 n=0,15
         e(n) = real(dble(x(n)) - y(n))
         f(n) = abs(e(n)/real(y(n)))
         print 5,n,x(n),real(y(n)),e(n),f(n)
 3    continue
c
 4    format (a6,a10,a15,a16,a19)
 5    format(1x,i5,4(2x,e13.6))
      stop
      end