anchor.diff:              Ep = Ep - G * m(j) * m(i) / sqrt(norm2(r(i, :) - r(j, :))**2 + epsilon2)
   
            end do
  -     
  +
         end do
  -     
  +
         E = Ec + Ep
   
      end subroutine compute_energy
  - 
  +
      subroutine integrate(f, df, dt)
         implicit none
  -  
  +
         real(xp), intent(in) :: dt
         real(xp), dimension(:, :), intent(inout) :: f, df
  -  
  +
         f = f + df * dt
  -  
  +
      end subroutine integrate
  - 
  +
   end module physics
  
positive.code: 
        real(kind = xp), dimension(:, :), intent(in)  :: r
        real(kind = xp), dimension(:, :), intent(out) :: v
    
        real(kind = xp) :: omega
    
        omega = 0.5_xp / pi
        v(:, 1) =   omega * r(:, 2)
        v(:, 2) = - omega * r(:, 1)
        v(:, 3) = 0._xp
   
     end subroutine initial_speeds
     
     subroutine compute_initial_variables()
        implicit none
  
  
negative.code:          end do
  
        end do
  
     end subroutine compute_force
  
     subroutine compute_energy (m, r, v, Ec, Ep, E)
        implicit none
  
        real(kind=xp), dimension(:),    intent(in) :: m
        real(kind=xp), dimension(:, :), intent(in) :: r, v
  
        real(kind=xp), intent(out) :: Ec, Ep, E
  
        integer :: i, j
  
        Ec = 0._xp
  