!........................................................................
!
! Subroutine :
!
! Description:
!
! Arguments  :          
!
! Mod/Commons:    
!
! Calls      :      
!
! Author     : 
!
! Modified   :     
!             
!........................................................................
!
!
! $Log$
! Revision 1.6  2007/01/30 16:15:14  dcs
! merged with branch_bmad_1.
!
! Revision 1.2  2003/04/30 17:14:54  cesrulib
! dlr's changes since last import
!
! Revision 1.1.1.1  2002/12/13 19:23:30  cesrulib
! import bmadz
!
!
!........................................................................
!
!
subroutine sex_kick_calc (ele, orb, dj)

  use bmad



  use nonlin_mod
  implicit none

  type (sextupole_res_struct) res
  type (ele_struct) ele
  type (coord_struct) orb, j_orb

  real(rp) dj(3), sqrt_j_vec(3), phi_vec(3), k2l, theta, factor, fac3(3)

  integer k

!

  dj = 0
  call convert_coords ('LAB', orb, ele, 'ACTION', j_orb)
  sqrt_j_vec = sqrt(j_orb%vec(1:5:2))
  phi_vec    = j_orb%vec(2:6:2)
  call sextupole_resonance_calc (ele, res)
  k2l = ele%value(k2$) * ele%value(l$)

  do k = 1, res%n_res
    theta = sum(res%a(k)%iq * phi_vec)
    where (sqrt_j_vec /= 0 .or. res%a(k)%ij /= 0)
      fac3 = sqrt_j_vec**res%a(k)%ij
    elsewhere
      fac3 = 1
    end where
    factor = k2l * product(fac3)
    dj(1) = dj(1) + factor * (res%a(k)%dj_cos * cos(theta) + &
                                      res%a(k)%dj_sin * sin(theta))
    theta = sum(res%b(k)%iq * phi_vec)
    where (sqrt_j_vec /= 0 .or. res%b(k)%ij /= 0)
      fac3 = sqrt_j_vec**res%b(k)%ij
    elsewhere
      fac3 = 1
    end where
    factor = k2l * product(fac3)
    dj(2) = dj(2) + factor * (res%b(k)%dj_cos * cos(theta) + &
                                       res%b(k)%dj_sin * sin(theta))
  enddo

end subroutine