PN Subroutine

  1. astro_module.f90
  2. astro_module
  3. PN

public subroutine PN(p, r, u)

Convert a p-vector into modulus and unit vector.

Status: vector/matrix support routine.

Note

 If P is null, the result is null.  Otherwise the result is
 a unit vector.

History

  • IAU SOFA revision: 2006 November 13

Arguments

TypeIntentOptionalAttributesName
real(kind=wp), intent(in), dimension(3):: p

p-vector
real(kind=wp), intent(out) :: r

modulus
real(kind=wp), intent(out), dimension(3):: u

unit vector

Calls

proc~~pn~~CallsGraph proc~pn PN proc~zp ZP proc~pn->proc~zp proc~sxp SXP proc~pn->proc~sxp

Called by

proc~~pn~~CalledByGraph proc~pn PN proc~apcs APCS proc~apcs->proc~pn proc~apcg APCG proc~apcg->proc~apcs proc~apcs13 APCS13 proc~apcs13->proc~apcs proc~apco APCO proc~apco->proc~apcs proc~apcg13 APCG13 proc~apcg13->proc~apcg proc~apci APCI proc~apci->proc~apcg proc~apco13 APCO13 proc~apco13->proc~apco proc~apci13 APCI13 proc~apci13->proc~apci proc~atco13 ATCO13 proc~atco13->proc~apco13 proc~atoc13 ATOC13 proc~atoc13->proc~apco13 proc~atci13 ATCI13 proc~atci13->proc~apci13 proc~atic13 ATIC13 proc~atic13->proc~apci13

Contents

Source Code

PN

Source Code

    subroutine PN ( p, r, u )

    implicit none

    real(wp),dimension(3),intent(in) :: p !! p-vector
    real(wp),intent(out) :: r !! modulus
    real(wp),dimension(3),intent(out) :: u !! unit vector

    real(wp) :: w

    !  Obtain the modulus and test for zero.
    call PM ( p, w )
    if ( w == 0.0_wp ) then
       !  Null vector.
       call ZP ( u )
    else
       !  Unit vector.
       call SXP ( 1.0_wp/w, p, u )
    end if

    !  Return the modulus.
    r = w

    end subroutine PN