anchor.diff:      i1 = A(i)
       do j=1, size(A)
           j1 = A(j)
  -        call set_next_eigeval(iunt, kpr, j1, i1, 0, w, dk)
  +        call set_next_eigeval(iunt, g, kpr, j1, i1, 0, w, dk, prg)
       end do
   end do
   
  
positive.code: 
  end program
  
  subroutine set_next_eigeval(iunt, kp, i, j, k, w, dk)
      implicit none
      integer(kind=4), intent(in) :: iunt, i, j, k, w
      real(kind=8), intent(in) :: kp(3), dk
  
      write(unit=iunt,fmt='(F15.10,F15.10,F15.10,F5.1)') kp(1)+i*dk, kp(2)+j*dk, kp(3)+k*dk, dble(w)
      ! write(unit=iunt,fmt='(I5,I5,I5)') i, j, k
      return
  end subroutine
negative.code:     i1 = A(i)
      do j=1, size(A)
          j1 = A(j)
          call set_next_eigeval(iunt, g, kpr, j1, 0, i1, w, dk, prg)
      end do
  end do
  
  