NAME:
	ufun
PURPOSE:
	Damping function for new likelihood function
	following Richard.L White 

CALLING SEQUENCE:
	u = ufun(n, t, obs, cal)

INPUTS:
	n = 1 means no effect!!!
	t should be > 0
	obs = observed array
	obs = the observed array
	calc = the calculated array
	"obs" and "cal" SHOULD BE EXPRESSED IN UNITS
	OF MEASURMENT UNCERTAINTIES

KEYWORDS:

METHOD:
	Image restoration Using the Damped
 	Richardson-Lucy Method, in The restoration of HST Image 
	and Spectra II, Space Telecsope Science institute, 1994
	R.J. Hanisch and R.L.White eds, 104-110

 CALLED BY:
	adrlb
HISTORY:
	J. Sylwester, Apr 1996, written

 unpack_trace
 Datify-style hack to deal with unpacking TRACE images into datify-style flat fits images.

 Written quickly without much regard for style, Craig DeForest, 25-Feb-1999

 Principally called by DATIFY.PRO when it counters a TRACE-like file.
 CALLS:
 CALLED BY
	datify

 NAME:
 UPDATE_LINE_TEMPLATES

 PURPOSE:
 This procedure looks for files that contain line templates

 CATEGORY:
 XRAY, GAMMA_RAYS, SPECTRUM, SPEX

 CALLING SEQUENCE:
 update_line_templates, FILE=['template1.txt','template2.txt]

 INPUT KEYWORDS:
 FILE - name(s)/pattern(s) of template file(s) to read.
 PATH - path(s) to search for template file(s).

 OUTPUT KEYWORDS:
 N_LINE - number of valid line complexes found in template files.
 ERR_MSG - string containing error message.  Null if no error occurred.
 ERR_CODE - [0 / 1] if an error [did / did not] occurr.

 CALLED BY:
	LINE_COMPLEX
 COMMON BLOCKS:
 LINE_COMPLEX_COM

 CALLS: ***
	CHECKVAR [1], CONCAT_DIR [1], CONCAT_DIR [2], CONCAT_DIR [3], LOC_FILE [1]
	LOC_FILE [2], LOC_FILE [3], checkvar [2], concat_dir [4], curdir [1], curdir [2]
	get_logenv [1], get_logenv [2], is_member [1], is_member [2], rd_tfile [1]
	rd_tfile [2]
 MODIFICATION HISTORY:
   23-July-2002, Paul Bilodeau - added checking for empty strings in
     complex_def_files variable.
   19-aug_2002, Paul Bilodeau - Calculate N_LINE in this routine.
     Added calls to concat_dir and curdir.

 Project     : CHIANTI

       CHIANTI is an atomic database package for the calculation of
       continuum and emission line spectra from astrophysical plasmas. It is a 
       collaborative project involving the Naval Research Laboratory
       (Washington DC, USA), the Arcetri Observatory (Firenze, Italy), and the
       Cambridge University (United Kingdom).
 
                   
 Name        : USE_CHIANTI
               
 Purpose     : Sets up system variables for use of CHIANTI routines
               
 Explanation : The  CHIANTI software uses system variables
               that have to be defined. This routine is called by the 
               CHIANTI routines if these system variables are not defined.

               ** If one is using the solar-soft package, these should 
               already be defined*****.

               ** If the CHIANTI package is used as stand-alone, then 
               this routine can be used for the setup with e.g.:

               use_chianti,'/home/data/chianti/'

               if /home/data/chianti/ points to the actual place where 
               the CHIANTI top directory is.

               
 Use         : IDL> use_chianti, '/home/data/chianti/', $
                                 [ioneq= , abund=]
    
 Inputs      : None
               
 Opt. Inputs : The full pathname of the CHIANTI top directory.
               
 Outputs     : None
               
 Opt. Outputs: None
               
 Keywords    : IONEQ  - to define the default ionization eq. file to be used.
               ABUND  -  to define the default abundance file to be used.

 Calls       : ***
	CONCAT_DIR [1], CONCAT_DIR [2], CONCAT_DIR [3], DEVICELIB [1], DEVICELIB [2]
	FILE_EXIST [2], concat_dir [4], dir_exist [1], dir_exist [2], file_exist [1]
	file_exist [3]
 Common      : None
               
 Restrictions: None
               
 Side effects: None
               
 Category    : 
               
 Prev. Hist. : Based on use_dere_chianti, written by C D Pike, RAL

 Written     : Giulio Del Zanna (GDZ)  DAMTP  (University of Cambridge, UK) 
               
 Modified    : Version 1, GDZ 10-Oct-2000
               Version 2, GDZ 10-Jan-2001
               added the definition of the !abund_file

               V. 3, GDZ, 2-May-2002 Modified substantially, adding a new
               system variable.

               V.4, 10-July-2002 GDZ
                 Removed the definition of !chianti_top, upon request.

               V.5, 25-July-2002, GDZ 
                Fixed a problem with IDL versions earlier than 5.3 (the routine
                would not compile). ALso, introduced the use of concat_dir for
                cross-platform compatibility.
                    
               V.6, 06-Aug-02 GDZ
                 Changed the use of CHIANTI system variables. Added comments on
                 the which CHIANTI version is used.
               V.7 12-Aug-02 GDZ Changed default abundance file. Removed '***'
               V.8, GDZ 13-Feb-2003
                   Changed default ioneq  file, to include ALL the elements.

               V.9,  12-Aug-2005, GDZ 
                   Changed default ioneq file from mazzotta_etal_ext to 
                   mazzotta_etal_9.ioneq where ion fractions have been extended
                   up to 10^9 K. This is useful to avoid steps in the
                   emissivities at high-temperatures.

               V.10,  19-Sept-2005, GDZ 
                   made last version backward-compatible.


 Version     : V.10,  19-Sept-2005

 Name:
	 USE_VLTH
 Purpose:
 	This procedure sets the logical scalar USE_VLTH in the common block f_vth_com

 	if set, then thermal spectrum includes line spectrum from MEWE_SPEC
 Category:
	spectra, xrays
 Inputs:
	/set	Use Mewe_spec to generate thermal bremsstrahlung model
       /noset  Just use continuum spectrum from Brem_49.pro
       default is just the continuum spectrum

 Calls: ***
	CHECKVAR [1], checkvar [2]
 CALLED BY:
	FLARE_XRAY_MODEL, GE_WINDOW [1], HESSI_FLARE_SPECTRUM, HESSI_MODEL_COUNTS
 History:
	ras, 18-may-94