!---------------------------------------------------------------------------
!---------------------------------------------------------------------------
!---------------------------------------------------------------------------

subroutine pretzel_set (what, factor, u)

  use cesrv_struct
  use cesrv_interface

  implicit none

  type (universe_struct) :: u

  integer i, what

  real(rp) factor

! put pretzels to zero so factor works correctly

  call do_var_transfer (u%hsep_kick, 1.0_rp, 'ZERO', u, .false.)

  if (what == pretzel_off$) then
    call do_var_transfer (u%hsep_kick, factor, 'ZERO', u, .true.)
  elseif (what == pretzel_saved$) then
    call do_var_transfer (u%hsep_kick, factor, 'SAVED', u, .true.)
  elseif (what == pretzel_design$) then
    call do_var_transfer (u%hsep_kick, factor, 'DESIGN', u, .true.)
  else
    print *, 'ERROR IN PRETZEL_SET: UNKNOWN SWITCH: ', what
    call err_exit
  endif

  logic%pretzel = what
  logic%pretzel_factor = factor

  do i = 1, 98
    call var_bookkeeper(u%sex_k2%v(i), u%ring, u%orb)
  enddo

  call ring_calc (u)

end subroutine