C SAMPLE PROGRAM FOR DFMIN
C
      DOUBLE PRECISION A, B, XSTAR, TOL, DFMIN, F
      EXTERNAL F
      A     = 0.1D0
      B     = 0.9D0
      TOL   = 1.0D-5
      XSTAR = DFMIN (A, B, F, TOL)
      WRITE (*,*) 'DFMIN RESULTS'
      WRITE (*,'(2X,A,D18.10)') ' XSTAR =', XSTAR
      WRITE (*,*)
      WRITE (*,*) 'REFERENCE RESULTS FROM IBM PC/AT'
      WRITE (*,*) '  XSTAR =  0.8164961769E+00'    
      STOP
      END
C
      DOUBLE PRECISION FUNCTION F(X)
      DOUBLE PRECISION X
      F = X*(X*X - 2.0D0) - 5.0D0
      RETURN
      END