set_d2accel_dt2 Subroutine

  subroutine set_d2accel_dt2 ( this, d2at_dt2, d2ar_dt2, &
                                     d2atheta_dt2, d2aphi_dt2 )
  !! Routine that sets the second coordinate time derivative of the
  !! 4-acceleration.

    implicit none

    class(self_force), intent(inout) :: this
    !! The routine is called on this [[self_force]] object.
    real(wp), intent(in) :: d2at_dt2
    !! The second time derivative of the \(t\)-component of the 4-acceleration,
    !! \(\ddot{a}^t\).
    real(wp), intent(in) :: d2ar_dt2
    !! The second time derivative of the \(r\)-component of the 4-acceleration,
    !! \(\ddot{a}^r\).
    real(wp), intent(in) :: d2atheta_dt2
    !! The second time derivative of the \(\theta\)-component of the
    !! 4-acceleration, \(\ddot{a}^{\theta}\).
    real(wp), intent(in) :: d2aphi_dt2
    !! The second time derivative of the \(\phi\)-component of the
    !! 4-acceleration, \(\ddot{a}^{\phi}\).

    this%d2a_dt2 = (/ d2at_dt2, d2ar_dt2, d2atheta_dt2, d2aphi_dt2 /)
  end subroutine set_d2accel_dt2