subroutine osc_pcalc(lat, osc_start, osc_end, osc_kicker, wavelength, co, mode)
 use bmad
 use mode3_mod
 use input_mod
 use da_interface
 use da_mod
 
 implicit none
 type (lat_struct) lat
 type (coord_struct), allocatable :: co(:)
 type (normal_modes_struct) mode
 type(ele_struct), pointer :: ele2
 type(ele_struct), target :: ele
 type (osc_param_struct) osc_param

 character*16, osc_start, osc_end, osc_kicker
 character*16 wiggler_period_ch, wig_b_ch, ph
 
 integer ix_start/0/, ix_end/0/, ix_kick/0/
 integer i

 real(rp) beam_energy, wiggler_period, wig_k, gamma_e
 real(rp) r_xz
 real(rp) wavelength
 real(rp) wig_b
 
! locate start and end elements and compute matrix from start to end

   do i=1,lat%n_ele_track
    if(index(lat%ele(i)%name,osc_start) /= 0)then
      ix_start = i
    endif
    if(index(lat%ele(i)%name,osc_end) /= 0)then
      ix_end = i
    endif
    if(index(osc_kicker(1:10),lat%ele(i)%name(1:10)) /= 0)then
      ix_kick = i
      ele = lat%ele(i)
      ele2 => ele 
      if(ele%slave_status == super_slave$ .or. ele%slave_status == slice_slave$)ele2 =>pointer_to_lord(lat%ele(i),1)
   endif
   
   end do
      if(ix_start == 0)print *,osc_start,' not found'
      if(ix_end == 0)print *,osc_end,' not found'
      if(ix_kick == 0)then
          print *,'OSC_KICKER',' not found'
       else
          print '(a, es12.4,a,es12.4)',' OSC_KICKER: length = ', ele2%value(l$),'  Nperiods = ', ele2%value(n_period$)
       endif
       
   beam_energy = lat%ele(ix_kick)%value(e_tot$) 
  if(ix_kick <= 0)then
    print *, 'OSC_PCALC: OSC_KICKER not found'
!    stop
 endif
 osc_param%wavelength = wavelength
 gamma_e = beam_energy / mass_of(positron$)
! wiggler_period = 2.*gamma_e**2/(1+wig_k**2) *osc_param%wavelength  !helical undulator
! if(associated(ele2%value(n_pole$)))then
     if(ix_kick /= 0 .and. ele2%value(n_period$)/= 0)then
   wiggler_period = ele2%value(n_period$)
   wig_k = 93.36 *ele2%value(b_max$) * wiggler_period
else
   call read_a_line(' wiggler period ?',wiggler_period_ch)
   read(wiggler_period_ch,*)wiggler_period
   call read_a_line(' wiggler peak field ?',wig_b_ch)
   read(wig_b_ch,*)wig_b
   wig_k = 93.36*wig_b*wiggler_period
 endif
 call read_a_line('planar or helical (p/h) ?',ph)
 print '(a,es12.4,a,es12.4,a16,a16)', 'wiggler period = ',wiggler_period,' wig_B = ', wig_b,' wiggler type = ', ph
 if(index(ph, 'p') /= 0)osc_param%wavelength = wiggler_period/2./gamma_e**2 * (1+wig_k**2/2.)!planar undulator
   if(index(ph,'h') /= 0)osc_param%wavelength = wiggler_period/2./gamma_e**2 * (1+wig_k**2) !helical undulator

   osc_param%linear=.true.
   osc_param%t2mat=.true.
   osc_param%theta2 = .true.
   osc_param%det = .false.
   
   call osc_parameters(lat,ix_start, ix_end, co, osc_param, .true.)
   r_xz = (osc_param%Tmat(5,6)-osc_param%tilde_m56)/osc_param%tilde_m56  

   print *

   print *, 'Optical stochastic cooling insert parameters'
   print '(2(a,es12.4,10x))',' Beam Energy = ', beam_energy,'gamma_e = ', gamma_e
   print '(a,4(a,es12.4,10x))',' Wiggler:','B_max = ', lat%ele(ix_kick)%value(b_max$), '  wiggler_period = ', wiggler_period,'  K_param = ',wig_k,' Optical wavelength = ',osc_param%wavelength
   ele = lat%ele(ix_end)
   print '(a,3es12.4)',' Pickup: beta/alpha/gamma = ', ele%a%beta,ele%a%alpha,ele%a%gamma
   print '(a,2es12.4)',' kicker: eta/etap = ', lat%ele(ix_end)%x%eta,lat%ele(ix_end)%x%etap
   ele = lat%ele(ix_end)
   print '(a,es12.4)',' kicker: Curly H = ', (ele%x%eta**2*ele%a%gamma + ele%a%beta *(ele%x%etap)**2 + 2* ele%a%alpha*ele%x%etap*ele%x%eta)**.5
   print '(a,es12.4,a,es12.4)',' Horizontal emittance = ', mode%a%emittance, '     emit_max = ', osc_param%osc_emit_max
   print '(a,es12.4,a,es12.4)',' Fractional energy spread = ', mode%sige_e,'     dp/p_max = ', osc_param%osc_dp_max
   print '(a,es12.4)',' Ratio transverse/longitudinal rate = ', r_xz

   call check_bypass_linearity(lat,co,mode, ix_start, ix_end, osc_param)

 return
 end