uhat_dot Function

public pure function uhat_dot(u, udot) result(uhatd)

Time derivative of a unit vector.

Arguments

Type IntentOptional Attributes Name
real(kind=wp), intent(in), dimension(3) :: u

vector [u]
real(kind=wp), intent(in), dimension(3) :: udot

derivative of vector [du/dt]

Return Value real(kind=wp), dimension(3)

derivative of unit vector [d(uhat)/dt]


Called by

proc~~uhat_dot~~CalledByGraph proc~uhat_dot uhat_dot proc~from_ijk_to_lvlh_mat from_ijk_to_lvlh_mat proc~from_ijk_to_lvlh_mat->proc~uhat_dot proc~from_ijk_to_rsw_mat from_ijk_to_rsw_mat proc~from_ijk_to_rsw_mat->proc~uhat_dot proc~from_ijk_to_vuw_mat from_ijk_to_vuw_mat proc~from_ijk_to_vuw_mat->proc~uhat_dot interface~from_ijk_to_lvlh from_ijk_to_lvlh interface~from_ijk_to_lvlh->proc~from_ijk_to_lvlh_mat interface~from_ijk_to_rsw from_ijk_to_rsw interface~from_ijk_to_rsw->proc~from_ijk_to_rsw_mat interface~from_ijk_to_vuw from_ijk_to_vuw interface~from_ijk_to_vuw->proc~from_ijk_to_vuw_mat proc~from_lvlh_to_ijk_mat from_lvlh_to_ijk_mat proc~from_lvlh_to_ijk_mat->interface~from_ijk_to_lvlh proc~from_rsw_to_ijk_mat from_rsw_to_ijk_mat proc~from_rsw_to_ijk_mat->interface~from_ijk_to_rsw proc~from_vuw_to_ijk_mat from_vuw_to_ijk_mat proc~from_vuw_to_ijk_mat->interface~from_ijk_to_vuw proc~relative_motion_test relative_motion_test proc~relative_motion_test->interface~from_ijk_to_lvlh proc~relative_motion_test->interface~from_ijk_to_rsw interface~from_lvlh_to_ijk from_lvlh_to_ijk interface~from_lvlh_to_ijk->proc~from_lvlh_to_ijk_mat interface~from_rsw_to_ijk from_rsw_to_ijk interface~from_rsw_to_ijk->proc~from_rsw_to_ijk_mat interface~from_vuw_to_ijk from_vuw_to_ijk interface~from_vuw_to_ijk->proc~from_vuw_to_ijk_mat

Source Code

    pure function uhat_dot(u,udot) result(uhatd)

    implicit none

    real(wp),dimension(3),intent(in) :: u      !! vector [`u`]
    real(wp),dimension(3),intent(in) :: udot   !! derivative of vector [`du/dt`]
    real(wp),dimension(3)            :: uhatd  !! derivative of unit vector [`d(uhat)/dt`]

    real(wp)              :: umag  !! vector magnitude
    real(wp),dimension(3) :: uhat  !! unit vector

    umag = norm2(u)

    if (umag == zero) then  !singularity
        uhatd = zero
    else
        uhat = u / umag
        uhatd = ( udot - dot_product(uhat,udot)*uhat ) / umag
    end if

    end function uhat_dot