anchor.diff:    y(1) = 3.9d0     ! u0
     y(2) = 1.1d0     ! v0
     y(3) = 2.8d0     ! w0
  -  rpar(1) = 1.2    ! a
  -  rpar(2) = 2.5    ! b
  +  rpar(1) = 1.2d0  ! a
  +  rpar(2) = 2.5d0  ! b
     rpar(3) = 1.d-5  ! ep
   
     ! set final solution
  
positive.code:      DJac(3,2) = 0.0
       DJac(3,3) = -1.d0/ep - u
    else 
       DJac = 0.d0
       DJac(3,3) = -1.d0/ep
    end if
    ier = 0
  
negative.code:   ytrue(3) = 2.4999733761419733
  
    ! set tolerances according to problem specifications
    atol = 1.d-9
    rtol = 1.d-6
    
    ! initialize vector module
  