rvcto_rvcfrom_icrf Subroutine

private subroutine rvcto_rvcfrom_icrf(from, to, eph, et, rc21, vc21, status_ok)

Returns the state of the from frame center w.r.t. the to frame center, at the specified ephemeris time et.

Arguments

Type IntentOptional Attributes Name
class(reference_frame), intent(in) :: from
class(reference_frame), intent(in) :: to
class(ephemeris_class), intent(inout) :: eph

for ephemeris computations (assumed to have already been initialized)
real(kind=wp), intent(in) :: et

ephemeris time [sec]
real(kind=wp), intent(out), dimension(3) :: rc21

position of from frame center w.r.t. to frame center
real(kind=wp), intent(out), dimension(3) :: vc21

velocity of from frame center w.r.t. to frame center
logical, intent(out) :: status_ok

true if there were no errors

Calls

proc~~rvcto_rvcfrom_icrf~~CallsGraph proc~rvcto_rvcfrom_icrf transformation_module::rvcto_rvcfrom_icrf get_rv get_rv proc~rvcto_rvcfrom_icrf->get_rv proc~from_primary_to_center transformation_module::two_body_rotating_frame%from_primary_to_center proc~rvcto_rvcfrom_icrf->proc~from_primary_to_center proc~from_primary_to_center->get_rv

Called by

proc~~rvcto_rvcfrom_icrf~~CalledByGraph proc~rvcto_rvcfrom_icrf transformation_module::rvcto_rvcfrom_icrf proc~transform transformation_module::reference_frame%transform proc~transform->proc~rvcto_rvcfrom_icrf proc~transformation_module_test transformation_module::transformation_module_test proc~transformation_module_test->proc~transform

Source Code

    subroutine rvcto_rvcfrom_icrf(from, to, eph, et, rc21, vc21, status_ok)

    !! Returns the state of the `from` frame center w.r.t. the `to` frame center,
    !! at the specified ephemeris time `et`.

    implicit none

    class(reference_frame),intent(in)    :: from
    class(reference_frame),intent(in)    :: to
    class(ephemeris_class),intent(inout) :: eph       !! for ephemeris computations (assumed to have already been initialized)
    real(wp),intent(in)                  :: et        !! ephemeris time [sec]
    real(wp),dimension(3),intent(out)    :: rc21      !! position of `from` frame center w.r.t. `to` frame center
    real(wp),dimension(3),intent(out)    :: vc21      !! velocity of `from` frame center w.r.t. `to` frame center
    logical,intent(out)                  :: status_ok !! true if there were no errors

    ! local variables
    real(wp),dimension(6) :: rvc1  !! inertial state of `from` frame center w.r.t. `from` primary body
    real(wp),dimension(6) :: rvc2  !! inertial state of `to`   frame center w.r.t. `to`   primary body
    real(wp),dimension(6) :: rvb21 !! inertial state of `from` primary body w.r.t. `to`   primary body
    real(wp),dimension(6) :: rvc21 !! inertial state of `from` frame center w.r.t. `to`   frame center

    ! get TO primary body -> FROM primary body state [inertial]
    call eph%get_rv(et,from%primary_body,to%primary_body,rvb21,status_ok)
    if (status_ok) then

        ! currently, only the two-body rotating frames may be
        ! centered somewhere other than the primary body.
        select type (from)
        class is (two_body_rotating_frame)
            call from%from_primary_to_center(eph,et,rvc1,status_ok)
        class default
            rvc1 = zero
        end select

        if (status_ok) then

            select type (to)
            class is (two_body_rotating_frame)
                call to%from_primary_to_center(eph,et,rvc2,status_ok)
            class default
                rvc2 = zero
            end select

            if (status_ok) then
                rvc21 = rvb21 + rvc1 - rvc2
                rc21  = rvc21(1:3)
                vc21  = rvc21(4:6)
                return
            else
                write(error_unit,'(A)') 'Error in rvcto_rvcfrom_icrf: '//&
                                         'Could not compute center of TO frame.'
            end if

        else
            write(error_unit,'(A)') 'Error in rvcto_rvcfrom_icrf: '//&
                                     'Could not compute center of FROM frame.'
        end if

    else !error
        write(error_unit,'(A)') 'Error in rvcto_rvcfrom_icrf: '//&
                                 'Could not compute translation.'
    end if

    ! we end up here if there was an error:
    rc21  = zero
    vc21 = zero

    end subroutine rvcto_rvcfrom_icrf