s ~ sqrt(psi)
This is the radial coordinate as used internally in i2MEX
integer, intent(in) :: ns
real(i2mex_r8), intent(in) :: psi(*)
real(i2mex_r8), intent(out) :: s(*)
integer, intent(out) :: ier
d s/ d psi
integer, intent(in) :: ns
real(i2mex_r8), intent(in) :: psi(*)
real(i2mex_r8), intent(out) :: ds(*)
integer, intent(out) :: ier
d^2 s/ d psi^2
integer, intent(in) :: ns
real(i2mex_r8), intent(in) :: psi(*)
real(i2mex_r8), intent(out) :: d2s(*)
integer, intent(out) :: ier