PRO dustem_fit_sed_ext_pol_example,model=model $

                                  ,sed_file=sed_file $
                                  ,ext_file=ext_file $
                                  ,Nitermax=Nitermax $

                                  ,fits_save=fits_save $

                                  ,wait=wait $

                                   ,noobj=noobj $
                                   ,help=help $
                                  ,verbose=verbose

;+
; NAME:
;    dustem_fit_sed_ext_pol_example  
;

; PURPOSE: This routine is an example of how to fit an observational
; data in emission + extinction SED (StokesI,Q,U) with DustEM and
; DustEMWrap.

;  
; See the DustEMWrap User Guide for more information.
;
; CATEGORY:
;    DustEMWrap, Distributed, High-Level, User Example
;
; CALLING SEQUENCE:

;    dustem_fit_sed_ext_pol_example[,model=][sed_file=][ext_file=][,Nitermax=][,fits_save=][,/help,/wait,/verbose,/noobj]

;
; INPUTS:
;    None
;
; OPTIONAL INPUT PARAMETERS:
;    None
;
; OUTPUTS:
;    None
;
; OPTIONAL OUTPUT PARAMETERS:
;    Plots, results structure in binary FITS table format
;
; ACCEPTED KEY-WORDS:

;    model = specifies the interstellar dust mixture used by
;            DustEM. See userguide or dustem_test_model_exists.pro
;            for more details about available models in current release.

;    sed_file = string naming the path to text file in .xcat format that
;          describes the observational SED. If not set, the file
;          'Data/EXAMPLE_OBSDATA/example_SED_2.xcat' is used.  
;    ext_file = string naming the path to text file in .xcat format that
;          describes the observational extinction SED. If not set, the file

;          'Data/EXAMPLE_OBSDATA/Mathis90Fitz99_DISM_NH20.xcat' is used.  

;    Nitermax = maximum number of fit iterations. Default is 5.

;    fits_save = if set, save the fit results in a binary

;               FITS file. The code then restore this file and plots
;               the results using the saved results information.
;    help      = if set, print this help
;    wait      = if set, wait this many seconds between each step of
;                the code (for illustration purposes)
;    verbose      = if set, subroutines will run in verbose mode

;    noobj     = if set, runs with no object graphics

;
; COMMON BLOCKS:
;    None
;
; SIDE EFFECTS:
;    None
;
; RESTRICTIONS:
;    The DustEM fortran code must be installed
;    The DustEMWrap IDL code must be installed
;
; PROCEDURES AND SUBROUTINES USED:

;
; EXAMPLES
;    dustem_fit_sed_ext_pol_example

;    dustem_fit_sed_ext_pol_example,Nitermax=1,fits_save='/tmp/mysavefile.fits'
;    dustem_fit_sed_ext_pol_example,model='G17_MODELC'

;
; MODIFICATION HISTORY:
;    Written by JPB Apr-2011
;    Evolution details on the DustEMWrap gitlab.
;    See http://dustemwrap.irap.omp.eu/ for FAQ and help.  
;-

IF keyword_set(help) THEN BEGIN

  doc_library,'dustem_fit_sed_ext_pol_example'

  goto,the_end
END

IF keyword_set(model) THEN BEGIN
  use_model=strupcase(model)
ENDIF ELSE BEGIN

  use_model='G17_MODELD'    

ENDELSE

exists=dustem_test_model_exists(use_model,/pol)
if exists ne 1 then $
   message,'Unknown/unpolarized dust model: '+use_model

use_window=2       ; default graphics window number to use for plotting the results

use_verbose=0
if keyword_set(verbose) then use_verbose=1

use_Nitermax=5        ; maximum number of iterations for the fit
IF keyword_set(Nitermax) THEN use_Nitermax=Nitermax

dustem_define_la_common

;=== Set the (model-dependent) parameters that you want to fit
;=== Refer to the DustEM and DustEMWrap userguides for an explanation
;    of the different grain types

;=== Set the (model-dependent) parameters that you want to fit (pd),
;=== their initial values (iv)
;=== and whether they are bounded (ulimed,llimed,llims,ulims).
;=== Fixed parameters (fpd) and their values (fiv) are also set here.
;=== Refer to the DustEM and DustEMWrap User guides for an explanation
;=== of the physical meaning of dust model and plug-in parameters, and
;=== how to specify them.

;=== Example is provided for G17_MODELD 

;=== If you choose a different dust model, you will need to adjust the
;=== parameter information accordingly.

pd = [ $
     '(*!dustem_params).grains(0).mdust_o_mh',$         ;PAH0 mass fraction
     '(*!dustem_params).grains(1).mdust_o_mh',$         ;amCBE mass fraction
     '(*!dustem_params).grains(2).mdust_o_mh',$         ;aSil

     'dustem_plugin_modify_dust_pol_2', $

     'dustem_plugin_modify_dust_polx_2' ]

true_vals = [5.4e-4, 6.4e-4,4.8e-4, 48., 52] ; these are the true values that will be used to generate the data
iv = true_vals+[2.00E-4,-2.00E-4,2.00E-4,10, -10] ; this is the vector of starting guesses for the fit

Npar=n_elements(pd)
ulimed=replicate(0,Npar)

llimed=replicate(1,Npar) & llimed[3]=0 & llimed[4]=0

llims=replicate(1.e-15,Npar)

use_polarization=1

;=== Fixed parameters
fpd=[ $
    '(*!dustem_params).G0' ,  $     ;multiplicative factor to total ISRF
    'dustem_plugin_continuum_2' $       ;intensity of a BB continuum
    ]

;=== Initial parameter values for fixed parameters
fiv=[ $
    1. , $                      ;multiplicative factor to total ISRF
    3.e-3$                      ;intensity of BB continuum
]

if keyword_set(wait) then begin
   message,'Finished setting dust model and plug-in parameters: '+use_model,/info
   wait,wait
end

;== INITIALISE DUSTEM

dustem_init,model=use_model,polarization=use_polarization

!dustem_nocatch=1

!dustem_verbose=use_verbose

IF keyword_set(noobj) THEN !dustem_noobj=1
!EXCEPT=2 ; for debugging

;=== READ OBSERVATIONAL EXTINCTION DATA 
;=== IF THE USER DOES NOT PROVIDE AN EXTINCTION CURVE FILE , WE READ MATHIS TO INITIALISE THE OBSERVATIONAL STRUCTURE.

dir=!dustem_wrap_soft_dir+'/Data/EXAMPLE_OBSDATA/'

use_ext_file=dir+'Mathis90Fitz99_DISM_NH20.xcat' 
IF keyword_set(ext_file) THEN use_ext_file=ext_file
ext=read_xcat(use_ext_file,/silent)
IF not keyword_set(ext_file) THEN BEGIN
   message, 'You have not provided an extinction curve. I will generate one from the '+use_model+' model',/info
   ;;=== CREATE ENTRIES FOR ALL STOKES (OTHERWISE NEXT CALL TO
   ;;=== DUSTEM_SET_DATA WILL COMPLAIN SINCE WE HAVE INITIALISED
   ;;=== DUSTEM IN POLARIZATION MODE
   ;;=== WE ASSUME THAT A USER-PROVIDED EXT CURVE WILL SATISFY ALL REQUIREMENTS
   ext.EXT_I=1.
   for i=4l,n_tags(ext)-1 do begin
      ext.(i) = 1.E-15
   endfor
ENDIF   



;=== READ OBSERVATIONAL EMISSION DATA 
;=== IF THE USER DOES NOT PROVIDE A SED FILE , WE READ AN EXAMPLE_SED FILE TO INITIALISE THE OBSERVATIONAL STRUCTURE.

dir=!dustem_wrap_soft_dir+'/Data/EXAMPLE_OBSDATA/'

file=dir+'example_SED_3.xcat'

if keyword_set(sed_file) then file=sed_file 

sed=read_xcat(file,/silent)

IF not keyword_set(sed_file) THEN BEGIN
   message, 'You have not provided an SED. I will generate one from the '+use_model+' model',/info
 ;;=== CREATE ENTRIES FOR ALL STOKES (OTHERWISE NEXT CALL TO
   ;;=== DUSTEM_SET_DATA WILL COMPLAIN SINCE WE HAVE INITIALISED
   ;;=== DUSTEM IN POLARIZATION MODE
   ;;=== WE ASSUME THAT A USER-PROVIDED SED CURVE WILL SATISFY ALL REQUIREMENTS
   sed.StokesI=1.
   for i=4l,n_tags(sed)-1 do begin
      sed.(i) = 1.E-15
   endfor
ENDIF   

;=== HERE WE SET THE DATA SO THAT THE COMPUTE_ FUNCTIONS BELOW HAVE
;=== THE NECESSARY FIELDS AND INFORMATION

dustem_set_data,m_fit=sed,m_show=sed,x_fit=ext,x_show=ext 

;== SET INITIAL VALUES AND LIMITS OF THE PARAMETERS FOR THE FIT 
;== AND ACTIVATE ANY PLUGINS (HENCE WE NEED TO DO THIS BEFORE THE COMPUTE_ CALLS)
dustem_init_params,use_model,pd,iv,fpd=fpd,fiv=fiv,ulimed=ulimed,llimed=llimed,ulims=ulims,llims=llims,polarization=use_polarization

if keyword_set(wait) then begin
   message,'Finished initializing DustEMWrap, including plugins and fixed parameters',/info
   wait,wait
end

if not keyword_set(ext_file) then begin
;== GENERATE THE EXTINCTION DATA USING THE MODEL AND TRUE VALUES
   ext.EXT_I = dustem_compute_ext(true_vals,st=st)
   toto = dustem_compute_stokext(true_vals,st=st,Qext_spec=dustem_qext,Uext_spec=dustem_uext)
   ext.EXT_Q = toto[0]
   ext.EXT_U = toto[1]
end

IF not keyword_set(sed_file) THEN BEGIN
;== GENERATE THE EMISSION DATA USING THE MODEL AND TRUE VALUES
   sed.StokesI = dustem_compute_sed(true_vals,st=st)
   toto = dustem_compute_stokes(true_vals,st=st,Q_spec=dustem_qsed,U_spec=dustem_used)
   sed.StokesQ = toto[0]
   sed.StokesU = toto[1]
end

;=== RESET THE OBSERVATIONAL STRUCTURE IF WE HAVE GENERATED DATA USING
;=== A MODEL
if not keyword_set(ext_file) or  not keyword_set(sed_file) THEN BEGIN

   dustem_set_data, m_fit=sed,m_show=sed,x_fit=ext,x_show=ext

   if keyword_set(wait) then begin
      message,'Finished generating data from the model '+use_model,/info
      wait,wait
   end

end

;== INFORMATION TO RUN THE FIT
tol=1.e-10  ;fit tolerence

;=== INFORMATION TO MAKE THE PLOT
;=== _x/_extinction means extinction plots, _m/_emissions means emission plots

xr_x = [0.01,30]

yr_x = [5.00E-8,10]

xr_m = [1.,5e5]
yr_m = [5e-8,1.00e6]

tit_m='Spectral Energy Distribution' 
tit_x='Dust Optical Depth' 

;===  RUN THE FIT

t1=systime(0,/sec)
res=dustem_mpfit_data(tol=tol,Nitermax=use_Nitermax,gtol=gtol $

                      ,/xlog,/ylog,xr_m=xr_m,yr_m=yr_m,xr_x=xr_x,yr_x=yr_x,xtit=xtit,ytit=ytit,tit_m=tit_m,tit_x=tit_x $

                      ,legend_xpos=legend_xpos,legend_ypos=legend_ypos $

                      ,errors=errors,chi2=chi2,rchi2=rchi2,show_plot=show_plot)

t2=systime(0,/sec)

if keyword_set(wait) then begin
   message,'Finished running DustEMWrap, using Niters: '+strtrim(string(use_Nitermax),2),/info
   message,'Time taken [sec]: '+sigfig(t2-t1,2,/sci),/info
   wait,wait
end

;=== MAKE THE FINAL PLOT
IF keyword_set(postscript) THEN BEGIN
    dir_ps='./'
    set_plot,'PS'
    ps_file=dir_ps+postscript
    device,filename=ps_file,/color
ENDIF

IF !dustem_noobj THEN BEGIN 
  dustemwrap_plot_noobj,(*(*!dustem_fit).CURRENT_PARAM_VALUES),st=dummy,xr=xr,/xstyle,yr=yr,/ysty,/ylog,/xlog,tit_m=tit_m+' (Final fit)',tit_x=tit_x+' (Final fit)' 
ENDIF ELSE BEGIN
  dustemwrap_plot,(*(*!dustem_fit).CURRENT_PARAM_VALUES),st=dummy,xr=xr,/xstyle,yr=yr,/ysty,/ylog,/xlog,tit_m=tit_m+' (Final fit)',tit_x=tit_x+' (Final fit)' 
ENDELSE

IF keyword_set(postscript) THEN BEGIN
  set_plot,'X'
  device,/close
  message,'Wrote '+ps_file,/info
ENDIF

if keyword_set(wait) then begin
   message,'Made the plot of the final results',/info
   wait,wait
end


IF keyword_set(fits_save) THEN BEGIN
   message,'Writing out results structure: '+fits_save,/info
   dustem_write_fits_table,filename=fits_save,help=help
;=== At this point, you could erase all dustem system variables, or exit idl... all the
;=== information needed to recover the results and remake the plots has been saved in the FITS table

;;    dustem_read_fits_table,filename=fits_save,dustem_st=dustem_spectra_st
;; ;==== plot result taken from the saved fits table
;;    res=*(*!dustem_fit).CURRENT_PARAM_VALUES
;;   ;If the user prefers non-OOP plotting then reset !dustem_noobj=1 here since dustem_init is called in reads_fits_table.
;;    IF !dustem_noobj THEN BEGIN
;;       dustemwrap_plot_noobj,res,st=dustem_spectra_st,xr=xr,/xstyle,yr=yr,/ysty,/ylog,/xlog,tit_m=tit_m+' (From Saved FITS file)',tit_x=tit_x+' (From Saved FITS file)'
;;    ENDIF ELSE BEGIN
;;       dustemwrap_plot,res,st=dustem_spectra_st,xr=xr,/xstyle,yr=yr,/ysty,/ylog,/xlog,tit_m=tit_m+' (From Saved FITS file)',tit_x=tit_x+' (From Saved FITS file)'
;;    ENDELSE

   IF keyword_set(wait) THEN BEGIN

      message,'Saved the results as FITS in the file: '+fits_save,/info

      wait,wait
   ENDIF

ENDIF

the_end:

message,'Finished dustem_fit_sed_ext_pol_example',/info

END