Return the toroidal flux/(2*pi) in res.
    The toroidal flux/(2*pi) is the integral of q d psi
integer, intent(in) :: ns
real(i2mex_r8), intent(in) :: psi(ns)
real(i2mex_r8), intent(out) :: res(ns)
integer, intent(out) :: ier
    Return d (toroidal flux/(2*pi))/d psi in res
    This is just the q profile
integer, intent(in) :: ns
real(i2mex_r8), intent(in) :: psi(ns)
real(i2mex_r8), intent(out) :: res(ns)
integer, intent(out) :: ier
    Return d^2 (toroidal flux/(2*pi))/d psi^2 in res
    This is just the d q/ d psi
integer, intent(in) :: ns
real(i2mex_r8), intent(in) :: psi(ns)
real(i2mex_r8), intent(out) :: res(ns)
integer, intent(out) :: ier