anchor.diff:  
     call HYPRE_StructVectorAssemble(hypre_x, ierr)
   
  -    ! now create the solver and solve the equation.
  +  ! now create the solver and solve the equation.
     ! Choose the solver
     call HYPRE_StructPCGCreate(MPI_COMM_WORLD, hypre_solver, ierr)
   
  
positive.code:   call HYPRE_StructPCGSetPrintLevel(hypre_solver, 1 ); ! 2 will print each CG iteration
    call HYPRE_StructPCGSetLogging(hypre_solver, 1);
  
    ! ! use an algebraic multigrid preconditioner
    call HYPRE_BoomerAMGCreate(precond, ierr)
    ! values taken from hypre library example number 5
    ! print less solver info since a preconditioner
  
negative.code:   ! External solver variables
    integer   :: offsets(2,5)
    integer :: i, j ! loop variables
    double precision, dimension(:), allocatable :: values
    integer   :: indicies(2)
    integer*8 :: hypre_grid
  