subroutine check_bypass_linearity(lat,orbit, mode,ix_start, ix_end, osc_param)
  use bmad
  use beam_mod
 
  use mode3_mod
  use da_mod

  implicit none
  type (lat_struct) lat
  type (beam_struct) beam, beam_start, beam_end
  type(beam_init_struct)beam_init 
  type(coord_struct), allocatable :: orbit(:)
  type (osc_param_struct) osc_param
  type (normal_modes_struct) mode
  
  integer i,j
  integer ix_start, ix_end
  integer nparticle/1000/
  real(rp)emit_x, emit_y, sig_z,sig_pz, ds
  real(rp) vec(6)
  logical err_flag
 character*1 word
  
!  call radiation_integrals(lat,orbit,mode)

 write(111,'(a,i10)')'nparticle = ',nparticle
 do i=0,4
     write(word,'(i1)')i

  emit_x = mode%a%emittance * (1+2.5*(i-1)) 
  emit_y = emit_x *0.5 ! mode%b%emittance 
  if(i == 0)then
     emit_x = mode%a%emittance
     emit_y=mode%b%emittance
  endif
  sig_z = mode%sig_z
  sig_pz = mode%sigE_E
   write(111,'(4(a,es12.4))')' emitx_'//word//' = ', emit_x,'; emity_'//word//' = ', emit_y,';  sigz_'//word//' = ', sig_z,';  sige_'//word//'=',sig_pz
end do
   write(111,'(a)')'exit'
  do i=0,4
  emit_x = mode%a%emittance * (1+2.5*(i-1)) 
  emit_y = emit_x *0.5 ! mode%b%emittance 
  if(i == 0)then
     emit_x = mode%a%emittance
     emit_y=mode%b%emittance
  endif
  sig_z = mode%sig_z
  sig_pz = mode%sigE_E

  beam_init%n_bunch = 1
  beam_init%dt_bunch = 0
  beam_init%n_particle=nparticle
  beam_init%bunch_charge = 1

  beam_init%a_emit = emit_x
  beam_init%b_emit = emit_y
  beam_init%sig_z = sig_z
  beam_init%sig_pz = sig_pz
    
  beam_init%center = orbit(0)%vec

  
  call init_beam_distribution(lat%ele(0), lat%param, beam_init, beam)
  beam_start = beam
  beam_end = beam

  call track_beam(lat,beam_start,ele1=lat%ele(0),ele2=lat%ele(ix_start), err=err_flag)
  call track_beam(lat,beam_end,ele1=lat%ele(0),ele2=lat%ele(ix_end), err=err_flag)
  write(111,'(a1,4(a8,es12.4))')'#',' emitx = ', emit_x,' emity = ', emit_y,' sigz = ', sig_z,' sige = ',sig_pz
  write(111,'(a1,a16,4x,6a16,4x,6a16)')'#','ds', 'x_pickup','xp_pickup','y_pickup','yp_pickup','z_pickup','pz_pickup', &
                             'x_kicker','xp_kicker','y_kicker','yp_kicker','z_kicker','pz_kicker'
  do  j=1, nparticle
    vec = beam_start%bunch(1)%particle(j)%vec -orbit(ix_start)%vec
    ds = osc_param%tmat(5,1)*vec(1) + osc_param%tmat(5,2)*vec(2) + osc_param%tmat(5,6)*vec(6)
    write(111,'(es16.6,4x,6es16.6,4x,6es16.6)')ds, &
         beam_start%bunch(1)%particle(j)%vec(1:6) - orbit(ix_start)%vec(1:6),&
         beam_end%bunch(1)%particle(j)%vec(1:6) - orbit(ix_end)%vec(1:6)
  end do
 write(111,'(/,a1,/)')'#'
 end do
 return
 end