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 3.2
c
c     Example of implicit function
c
c
c     file: ex3s32.f
c
      double precision  x,y,g,gp,gy,h
      data  x/0.0d0/, y/1.0d0/, h/0.1/, M/100/, N/4/
      g(x,y) = (3.0d0*x**4 - 1.0d0)*x**3 + (2.0d0*y**2 + 1.0d0)*y**3 - 3.0d0
      gp(x,y) = (10.0d0*y**2 + 3.0d0)*y**2
c
      print *
      print *,' Implicit Function Example'
      print *,' Section 3.2, Kincaid-Cheney'
      print *
c
      print 4
      print 7,0,x,y,g(x,y)
      do 3 i=1,M
         x = x + h
         gy = g(x,y)
         print 5
         do 2 j = 1,N
            y = y - gy/gp(x,y)
            gy = g(x,y)
            print 6,j,y,gy
 2       continue
         print *
         print 7,i,x,y,gy
 3    continue
c
 4    format(4x,'i',14x,'x',23x,'y',19x,'g(x,y)')
 5    format(7x,'j',13x,'y',19x,'g(x,y)')
 6    format(5x,i3,2x,d21.15,2x,d22.15)   
 7    format(2x,i3,2x,3(d22.15,2x))
      stop
      end