Function dustem_create_stokes, st, key=key, val=val, scope,help=help

;+
; NAME:
;    dustem_create_stokes
; PURPOSE:
;    Produces stokes emission parameters for the dust and synchrotron components
; CATEGORY:
;    DUSTEM Wrapper
; CALLING SEQUENCE:
;    dustem_create_stokes(st,key=key,val=val)
; INPUTS:
;    st (st = dustem_run(p_dim))
; OPTIONAL INPUT PARAMETERS:
;    key  = input parameter number
;    val  = input parameter value
; OUTPUTS:
;    out = array containing the stokes emission parameters associated to the dust/synchrotron component or a concatenated version for both
; OPTIONAL OUTPUT PARAMETERS:
;    None
; ACCEPTED KEY-WORDS:
;    help                  = if set, print this help
; COMMON BLOCKS:
;    None
; SIDE EFFECTS:
;    None
; RESTRICTIONS:
;    The dustem fortran code must be installed
;    The dustem idl wrapper must be installed
; PROCEDURE:
;    This is a dustem plugin
;-

IF keyword_set(help) THEN BEGIN
  doc_library,'dustem_create_stokes'
  goto,the_end
ENDIF

psi_ref_dust=0 
psi_ref_synch=0  

out=['']

IF keyword_set(key) THEN BEGIN 
  a=where(key EQ 1,count1)
  b=where(key EQ 2,count2)
  c=where(key EQ 3,count3)

 
  IF count3 NE 0 then begin
 
  frac_synch=(val(c))(0)
 
  endif else frac_synch=0.7 ;default value for synchrotron polarization fraction

 
  IF count1 NE 0 then begin
  psi_ref_dust=(val(a))(0)
  ;test to not devide by zero

  frac=st.polsed.em_tot/st.sed.em_tot
  tes=where(finite(frac) eq 0)
  frac(tes)=0.
  
  
  polar_ippsi2iqu,((st.sed).em_tot),Q_dust,U_dust,frac,psi_ref_dust
  
  out=[out,Q_dust,U_dust]
  endif
  
  IF count2 NE 0 then begin

  psi_ref_synch=(val(b))(0)
  
  
  frac=(*(*!dustem_plugin).synchrotron)/(*(*!dustem_plugin).synchrotron)
  tes=where(finite(frac) eq 0)
  frac(tes)=0.
  frac*=frac_synch
  polar_ippsi2iqu,(*(*!dustem_plugin).synchrotron),Q_synch,U_synch,frac,psi_ref_synch 
  out=[out,Q_synch,U_synch]
  endif 
  
ENDIF

scope=((*!dustem_scope).stokes)

return, out[1:*]
the_end:

end