FUNCTION dustem_compute_sed,p_dim,st,_extra=extra,out_st=out_st,wave0=wave0

;+
; NAME:
;    dustem_compute_sed
; PURPOSE:
;    Computes an SED from a given Dustem spectrum
; CATEGORY:
;    Dustem
; CALLING SEQUENCE:
;    sed=dustem_compute_sed(p_dim[,st=][,cont=][,_extra=][,/help])
; INPUTS:

;    p_dim      = parameter values (used only if st is not provided)

; OPTIONAL INPUT PARAMETERS:

;    st        = Dustem output structure, if provided, overrides p_dim

; OUTPUTS:
;    sed       = computed SED for filters in !dustem_data
; OPTIONAL OUTPUT PARAMETERS:

;    cont      = NIR continuum

;    out_st      = same as sed

; ACCEPTED KEY-WORDS:
;    help      = If set, print this help
; COMMON BLOCKS:
;    None
; SIDE EFFECTS:
;    None
; RESTRICTIONS:
;    The dustem idl wrapper must be installed
; PROCEDURE:
;    None
; EXAMPLES
;    
; MODIFICATION HISTORY:
;    Written by J.-Ph. Bernard
;    see evolution details on the dustem cvs maintained at CESR
;    Contact J.-Ph. Bernard (Jean-Philippe.Bernard@cesr.fr) in case of problems.
;-

IF keyword_set(help) THEN BEGIN
  doc_library,'dustem_compute_sed'
  dustem_sed=0.
  goto,the_end
ENDIF

IF not keyword_set(st) THEN BEGIN

  st=dustem_run(p_dim)

  dustem_activate_plugins,p_dim/(*(*!dustem_fit).param_init_values),res=res,st  

ENDIF

;If keyword_set(result) THEN result=st

if not keyword_set(wave0) then wave0 = 0.

; Convert into MJy/sr/1d20

fact = 1.e4*1.E20/(4.*!pi)/(3.e8/1.e-6/st.sed.wav)*1.e20/1.e7 ;this is correct despite the way it is presented (1.e4/1e.7*1e.20=1.e17 which is the factor to convert from ergs to Mega Janskys)

spec = st.sed.em_tot * fact

;ADDING PLUGIN TO SPECTRUM----------------
;if n_tags(!dustem_data.sed) gt 1 then begin ; executing only when !dustem_data.sed is set meaning that this allows for the creation of fake seds
for i=0L,n_tags(*!dustem_scope)-1 do begin

if total(strsplit((*(*!dustem_scope).(i)),'+',/extract) eq 'ADD_SED') then spec+=(*(*!dustem_plugin).(i))[*,0]

endfor
;endif
;------------------------------------------

if not isarray(spec) THEN stop 

;COMPUTE THE MODEL SED
dustem_sed = (*!dustem_data.sed).values * 0.

IF !dustem_do_cc NE 0 AND !dustem_never_do_cc EQ 0 THEN BEGIN
  message,'DOING color correction calculations',/info
ENDIF ELSE BEGIN
  message,'SKIPPING color correction calculations: we take previous values of cc',/info
ENDELSE

ind_sed=where((*!dustem_data.sed).filt_names NE 'SPECTRUM' and (*!dustem_data.sed).wav gt wave0,count_sed)
IF count_sed NE 0 THEN BEGIN

  filter_names=((*!dustem_data.sed).filt_names)[ind_sed]

  ;FOR ii=0L,n_elements(filter_names)-1 DO BEGIN
  ssed=dustem_cc(st.sed.wav,spec,filter_names,cc=cc)
  ;ENDFOR

  dustem_sed[ind_sed]=ssed

ENDIF ELSE BEGIN

  print,"**** WARNING **** NO FILTER defined in DATA for COLOUR CORRECTION" 

ENDELSE

;For spectrum data points, interpolate in log-log
;Linear interpolation leads to wrong values, in particular where few
;wavelengths points exist in the model (long wavelengths).
ind_spec=where((*!dustem_data.sed).filt_names EQ 'SPECTRUM',count_spec)
IF count_spec NE 0 THEN BEGIN

  dustem_sed[ind_spec]=interpol(spec,st.sed.wav,(((*!dustem_data.sed).wav)[ind_spec]))

;  dustem_sed(ind_spec)=10^interpol(alog10(spec),alog10(st.sed.wav),alog10((((*!dustem_data.sed).wav)(ind_spec))))
ENDIF
out_st=st

;clean pointers
heap_gc

the_end:

;VG : error in cc IRAS1 when no PAH 
j=where(dustem_sed ne dustem_sed,count)

if count gt 0 then dustem_sed[j]=0.

RETURN,dustem_sed

END