NAME:
	IMAGE_CONT

 PURPOSE:
	Overlay an image and a contour plot.

 CATEGORY:
	General graphics.

 CALLING SEQUENCE:
	IMAGE_CONT, A

 INPUTS:
	A:	The two-dimensional array to display.

 KEYWORD PARAMETERS:
 WINDOW_SCALE:	Set this keyword to scale the window size to the image size.
		Otherwise, the image size is scaled to the window size.
		This keyword is ignored when outputting to devices with 
		scalable pixels (e.g., PostScript).

	ASPECT:	Set this keyword to retain the image's aspect ratio.
		Square pixels are assumed.  If WINDOW_SCALE is set, the 
		aspect ratio is automatically retained.

	INTERP:	If this keyword is set, bilinear interpolation is used if 
		the image is resized.

 OUTPUTS:
	No explicit outputs.

 CALLS: ***
	IMAGE_C
 COMMON BLOCKS:
	None.

 SIDE EFFECTS:
	The currently selected display is affected.

 RESTRICTIONS:
	None.

 PROCEDURE:
	If the device has scalable pixels, then the image is written over
	the plot window.

 MODIFICATION HISTORY:
	DMS, May, 1988.

 PROJECT:  CHIANTI

       CHIANTI is an Atomic Database Package for Spectroscopic Diagnostics of
       Astrophysical Plasmas. It is a collaborative project involving the Naval
       Research Laboratory (USA), the University of Florence (Italy), the
       University of Cambridge and the Rutherford Appleton Laboratory (UK). 


 NAME: INTEGRAL_CALC
       
 PURPOSE:

       To compute the atomic data integral for use in column or volume
	emission measure work.

 CATEGORY:

       Scientific analysis

 EXPLANATION:

 	Defining

	G(T) = 0.83 * Fr(T) * N_j * A_ji / N_e

	where Fr(T) is the ionisation fraction (e.g., from Arnaud & 
	Rothenflug), N_j the relative population of level j, A_ji the 
	A-value for the j->i transition and N_e the electron density. The 
	0.83 is the ratio of hydrogen to free electrons, which is constant 
	above around 10^4 K. This function is sharply-peaked at a 
	temperature T_mem (the temperature of maximum emission, which can 
	be different from the temperature of maximum ionisation, T_max) 
	and so an oft-used approximation is to take G(T) constant in the 
	range log T_mem - 0.15 to log T_mem + 0.15 and zero outside. The 
	value of the constant, which we call C_lambda here, is then given 
	by

	C_lambda =    integral { G(T) dT }
                     --------------------
                  T_mem * (10^0.15 - 10^-0.15)

	If EM(s) is the column emission measure, F the flux (erg cm-2 s-1)
	in a line lambda, Ab the abundance of the element and DE (erg) the
	energy for the transition, then:

	F = DE * Ab * C_lambda * EM(s)

	If we are dealing with intensities I (erg cm-2 s-1 sr-1) then:

	4pi * I = DE * Ab * C_lambda * EM(s)

	This program extracts the ionisation balance and emissivities from 
	the CHIANTI database and calculates C_lambda for all lines in the 
	specified wavelength interval WRANGE by integrating over 
	0.02 dex temperature intervals.

	The C_lambda functions for all the lines in the selected wavelength 
	range WRANGE are displayed as well as the temperature of maximum 
	emission (T_mem), DE*C_lambda and 4pi/(DE*C_lambda). These latter 
	two quantities are useful for the emission measure analysis.

	Any combination of the displayed lines can then be blended and the 
	corresponding quantities for the blend will be displayed.

	The function Fr(T) * N_j * A_ji can also be plotted at this stage.

 CALLING SEQUENCE:

       INTEGRAL_CALC, IZ, ION, [WRANGE=WRANGE, /CHOOSE, DENS=DENS]

 EXAMPLES:

	INTEGRAL_CALC, 26, 13, WRANGE=[200,205], /CHOOSE

	INTEGRAL_CALC, 14, 10, WRANGE=[250,270], DENS=10.

 INPUTS:

	IZ:	The atomic number of the ion
	ION:	The spectroscopic number of the ion (e.g., 12 = XII)

 OPTIONAL INPUTS:

	DENS:	The density at which the emissivities are calculated 
		(default=10.)
	WRANGE: Wavelength range for which C_lambda functions are 
		calculated. If not given, then the 10 strongest lines 
		are printed.
	INDEX:	Particular elements in the emissivity structure can be 
		selected with INDEX. This allows integral_calc to be run 
		'silently'. The output is contained in the OUTSTR structure. 
		If index is given as, e.g., [7,8], then the C_lambda 
		functions for these two lines are summed and output.
	PATH:	Directly specify the directory path where the Chianti data 
		for the ion is found

       ABUND_FILE  The name of a CHIANTI abundance file. This is used for 
               calculating the proton to electron ratio. Default is 
               !abund_file.

       IONEQ_FILE  The name of a CHIANTI ion balance file. This is used for 
               calculating the proton to electron ratio and evaluating 
               the T_max of the ion. Default is !ioneq_file.

       RADTEMP  The blackbody radiation field temperature (default 
                6000 K).

       RPHOT    Distance from the centre of the star in stellar radius 
                units. I.e., RPHOT=1 corresponds to the star's surface. 
                (Default is infinity, i.e., no photoexcitation.)

 KEYWORDS:

	CHOOSE:	Allow ion balance calculations to be selected manually 
		(see choose_ioneq.pro routine).

 OPTIONAL OUTPUTS:

	OUTSTR:	A structure with the following tags

		.tmem	- the T_mem for the line(s)
		.dec	- total( de * c_lambda )
		.pidec	- 4 * pi / total( de * c_lambda )

	Only output when INDEX is specified.

 COMMON BLOCKS:

	None.

 CALLS: ***
	CH_GET_FILE, CONCAT_DIR [1], CONCAT_DIR [2], CONCAT_DIR [3], EMISS_CALC
	INT_TABULATED, READ_IONEQ, REVERSE, STR_SEP, concat_dir [4], get_ieq
 HISTORY:

	Ver.1: PRY, 28-JUN-97.
	Ver.2: PRY, 7-OCT-97. Added TEMPI and GOFT, for plotting.
	Ver.3: PRY, 31-JUL-98. Added PATH.
	Ver.4: PRY, 6-APR-99. Added INDEX, OUTSTR. Removed TEMPI and GOFT 
		(these can be got from the g_of_t routine).
       Ver.5: PRY, 9-Dec-01. Modified for v.4 of CHIANTI.

       V.6, 21-May-2002, Giulio Del Zanna (GDZ) 
                   generalized directory concatenation to work for
                   Unix, Windows  and VMS. 

       V.7, 06-Aug-02 GDZ
              Changed the use of CHIANTI system variables. 

       V.8, 6-Feb-2006, Peter Young
              Integration is now performed on d(logT) intervals, rather than
              dT intervals following problems identified by Luca Teriaca.
       

 VERSION     :   8, 06-Feb-06

 NAME: Intervals


 PURPOSE: Graphically select a set of intervals from an X array.
	   The X, Y plot is already displayed

 CATEGORY: Graphics, Fitting


 CALLING SEQUENCE: 
	Intervals(xdisplay, xselect ,xwidth=xwidth [,xinput=xinput] [,iselect=iselect] $
		 [,style=style] [,color=color])
                
; CALLS TO: point

 INPUTS:
       xdisplay - array of displayed abscissae
		if xdisplay is 2xn, then the two vectors are assumed
		to be the hi and lo edge of the data point, and 
		xwidth is calculated
	xwidth   - the width of each x bin, xdisplay taken at the center
 Optional inputs:
       style    - options
		 'contiguous'  The intervals are all contiguous.
		 'discrete'    The interval boundaries are chosen individually
		 'regular'     Two boundaries are chosen.  Intervals
			       are chosen for all bins between boundaries
                 Not used on direct input

       xinput   - for direct input of x edges, non-graphic
			       Non-graphic selection, a vector of 2xN time bins
			       are passed.  No display feedback.  For input times, 
			       the discrete mode is used although if a boundary is within 1% of an 
			       interval width it is chosen even if it violates the leading 
			       trailing edge rules for discrete selection
			       
       color    - can be used with routine linecolors

 OUTPUTS:
	xselect - the value of the boundaries for each interval selected 
		  2 x number of intervals
	iselect - the index of each boundary relative to xdisplay
		  for j=iselect(0,i) and k=iselect(1,i) the channels are
		  j through k-1, inclusive

 CALLS: ***
	ALPHA_PAGE [1], ALPHA_PAGE [2], CHECKVAR [1], CRANGE, DATATYPE [1], DATATYPE [2]
	DATATYPE [3], GRAPHICS_PAGE, POINT [1], checkvar [2], edge_products, point [2]
 CALLED BY:
	Modify Titles
 RESTRICTIONS: If selected points are not within the elements of xdisplay,
	then the element of xdisplay less than the selected value is chosen.
	Returns 0 if called by with device set to non-interactive and graphic
	input is required.

 PROCEDURE: Calls for a set of points to be input graphically or passed.  For graphical
	selection mode, lines are
	drawn showing each bin selected. Intervals may be chosen contiguously
	or individually.  Default is individual points. When specifying points
	interactively, the start and end of an interval defaults to the leading edge of
	the selected bin for a stream of contiguous intervals, and to the trailing edge
	for the last bin selected.

 MODIFICATION HISTORY:
	ras, 4 Oct 93
	ras, 12-feb-94, enable non-graphic selection

 NAME: Intervals


 PURPOSE: Graphically select a set of intervals from an X array.
	   The X, Y plot is already displayed

 CATEGORY: Graphics, Fitting


 CALLING SEQUENCE: 
	Intervals(xdisplay, xselect ,xwidth=xwidth [,xinput=xinput] [,iselect=iselect] $
		 [,style=style] [,color=color])
                
; CALLS TO: point

 INPUTS:
       xdisplay - array of displayed abscissae
		if xdisplay is 2xn, then the two vectors are assumed
		to be the hi and lo edge of the data point, and 
		xwidth is calculated
	xwidth   - the width of each x bin, xdisplay taken at the center
 Optional inputs:
       style    - options
		 'contiguous'  The intervals are all contiguous.
		 'discrete'    The interval boundaries are chosen individually
		 'regular'     Two boundaries are chosen.  Intervals
			       are chosen for all bins between boundaries
                 Not used on direct input

       xinput   - for direct input of x edges, non-graphic
			       Non-graphic selection, a vector of 2xN time bins
			       are passed.  No display feedback.  For input times, 
			       the discrete mode is used although if a boundary is within 1% of an 
			       interval width it is chosen even if it violates the leading 
			       trailing edge rules for discrete selection
			       
       color    - can be used with routine linecolors

 OUTPUTS:
	xselect - the value of the boundaries for each interval selected 
		  2 x number of intervals
	iselect - the index of each boundary relative to xdisplay
		  for j=iselect(0,i) and k=iselect(1,i) the channels are
		  j through k-1, inclusive

 CALLS: ***
	ALPHA_PAGE [1], ALPHA_PAGE [2], CHECKVAR [1], CRANGE, DATATYPE [1], DATATYPE [2]
	DATATYPE [3], GRAPHICS_PAGE, POINT [1], checkvar [2], edge_products, point [2]
 CALLED BY:
	Modify Titles
 RESTRICTIONS: If selected points are not within the elements of xdisplay,
	then the element of xdisplay less than the selected value is chosen.
	Returns 0 if called by with device set to non-interactive and graphic
	input is required.

 PROCEDURE: Calls for a set of points to be input graphically or passed.  For graphical
	selection mode, lines are
	drawn showing each bin selected. Intervals may be chosen contiguously
	or individually.  Default is individual points. When specifying points
	interactively, the start and end of an interval defaults to the leading edge of
	the selected bin for a stream of contiguous intervals, and to the trailing edge
	for the last bin selected.

 MODIFICATION HISTORY:
	ras, 4 Oct 93
	ras, 12-feb-94, enable non-graphic selection

 PROJECT:
   RHESSI/INVERSION

 NAME:
  inv_confidence_interval


 PURPOSE:
   Calculates a confidence interval - 1 sigma uncertanty on
   regularised solution


 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_confidence_interval,reg_sol,counts,ecounts,Alpha,Betta,U,W,opt,f_thin,Guess,Npass,reg_sol_err

 CALLS: ***
	INV_REG_SOLUTION
 INPUTS:

   reg_sol - vector, regularised solution
   counts  - vector, count flux
   ecounts - vector, 1 sigma uncertanty on count flux,

  Results of Generalised Singular Value Decomposition:
   alpha  - diagonal elements of SA
   betta  - diagonal elements of SB
   U,W    - matrixes consisting of decomposition products

   opt    - scalar, regularisation parameter
   f_thin - vector, forward-fit results
   Guess  - scalar (0 or 1.), use or not to use forward-fit in the constraint
   Npass  - scalar, number of Monte Carlo simulations to produce confidence interval

 OPTIONAL INPUTS:
   none

 OUTPUTS:

  reg_sol_err- vector, 1 sigma uncertanty on regularised solution

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	function_counts2photons, inv_counts2electrons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 30 September, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:

   inv_counts2electrons

 PURPOSE:

   Inversion of count spectrum using regularisation + GSVD method
   to obtain electron distribution

   Quick start with the inversion software
   http://www.astro.gla.ac.uk/users/eduard/rhessi/inversion/

  The bremsstrahlung produced photon flux spectrum I(eps)
 (photons/sec/cm^2/keV) at the Earth is given by the integral

  I(eps)=1/(4*!Pi*1AU^2)*\int_{eps}^{infinity} S(eps,e)F(e)de

  or in matrix form

  I=S*F

  where

  F(e) = <V*n*Fe(e)>
  F(e)  - density and volume weighted mean electron flux spectrum
          [electrons/sec/cm^2/keV]

  n - average number density of the surrounding plasma, [cm^-3]
  V - average emitting volume, [cm^3]
  S(eps,e) - differential bremsstrahlung cross-section, [cm^2/keV]
  Fe(e) -  mean electron flux spectrum [electrons/sec/cm^2/keV]

  The corresponding count flux spectrum in the X-ray detectors
  C(eps) [counts/sec/cm^2/keV] can be written in matrix form

  C = A*F, where A= DRM*S

  We know C and A and want to find F. This problem is ill-conditioned
  and regularision (additional constraints) should be applied.

  The code finds the solution for the problem as a function of lambda

  ||A*F-C||^2+lambda*||L*(F-F0)||^2=min

   where
   L  - constraint matrix
   F0 - thin-target fit from SPEX/OSPEX
   lambda - regularisation parameter found using descripancy principle


   ||A*F(lambda)-C||=reg_tweak*||dC||

   where
   dC  - 1 sigma uncertanty on count flux, [counts/sec/cm^2/keV]

   For details see:
   Kontar et al,2004,Sol Phys,225,293-309
   (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004SoPh..225..293K )
   Kontar et al,2005,Sol Phys,226,317-325
   (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005SoPh..226..317K )

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

 inv_counts2electrons,obj=obj,version=version,order=order,Npass=Npass,Guess=Guess,reg_tweak=reg_tweak


 CALLS: ***
	FCHECK, INV_GET_DATA_OSPEX, INV_REG_SOLUTION, INV_RESIDUALS
	inv_confidence_interval, inv_cross_section, inv_get_data_spex [1]
	inv_get_data_spex [2], inv_get_f_thin_ospex, inv_get_f_thin_spex, inv_gsvdcsq
	inv_make_constraint, inv_reg_parameter, inv_reg_resolution
	inv_save_electrons [1], inv_save_electrons [2]
 INPUTS:


 OPTIONAL INPUTS:

   obj       - OSPEX object name, if not set assumes old SPEX
   version   - string, version of the inversion code (currently only one version exist)
   order     - integer, regularization order. Can be 0 (default), 1, or 2.
   Npass     - integer, number of random noise realisations for the confidence strip.
                 Default is 30.
   Guess     - integer, 1 or 0 (default) - use or NOT use forward-fit in the constraint
   reg_tweak - float,  parameter to adjust the regularization parameter (default is 1).
   ee_in     - 2D array of electron bin energies (2,Bin_Number) in keV
               for example from 3 keV to 100 keV with 1 keV
               ee_in=transpose([[findgen(100)+3.],[findgen(100)+4.]])

 OUTPUTS:

 F(e) =<VnFe>  - regularised electron spectrum, [10^50 electrons/sec/cm^2/keV]
 dF            - 1 sigma error, [10^50 electrons/sec/cm^2/keV]
 e             - middle point electron energy, keV
 FWHM          - energy resolution of the regularised solution [keV]


 The results of the inversion is the regularised electron flux
 saved to file with the name date of the observation
 Format: Y1Y1Y1Y1M1M1D1D1_H1H1M1M1S1S1_H2H2M2M2S2S2
 corresponding to the start 1 and end 2 of the time interval

 The results are also plotted into PS files.

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   Version 1, eduard(at)astro.gla.ac.uk, 23 July, 2004
   30 September, 2005 - time interval added
   31 October, 2005   - now works with OSPEX
   15 january  2006   - added ee_in array option

 PROJECT:
   RHESSI/INVERSION

 NAME:

   inv_counts2photons

 PURPOSE:

   Inversion of count spectrum using regularisation + GSVD method
   to obtain model-independent photon spectrum

   Quick start with the inversion software
   http://www.astro.gla.ac.uk/users/eduard/rhessi/inversion/


  The observed count flux spectrum in the X-ray detectors
  C(eps) [counts/sec/cm^2/keV] can be written in matrix form

  C = DRM*F

  DRM - dynamic responce matrix of instrument

  We know C and DRM and want to find a photon flux F  [counts/sec/cm^2/keV].
  This problem is ill-conditioned
  and regularision (additional constraints) should be applied.

  The code finds the solution for the problem as a function of lambda

  ||DRM*F-C||^2+lambda*||L*(F-F0)||^2=min

   where

   ||...|| - L2 norm
   L       - constraint matrix
   F0      - a model of photon spectrum from SPEX/OSPEX
   lambda  - regularisation parameter found using descripancy principle


   ||A*F(lambda)-C||=reg_tweak*||dC||

   where
   dC  - 1 sigma uncertanty on count flux, [counts/sec/cm^2/keV]

   For details see:
   Kontar et al,2004,Sol Phys,225,293-309
   (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004SoPh..225..293K )
   Kontar et al,2005,Sol Phys,226,317-325
   (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005SoPh..226..317K )

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

 INV_COUNTS2PHOTONS,obj=obj,order=order,Npass=Npass,Guess=Guess,reg_tweak=reg_tweak

 CALLS: ***
	FCHECK, INV_GET_DATA_OSPEX, INV_REG_SOLUTION, INV_RESIDUALS
	inv_confidence_interval, inv_get_data_spex [1], inv_get_data_spex [2]
	inv_gsvdcsq, inv_make_constraint, inv_reg_parameter, inv_reg_resolution
	inv_save_photons, spex_current [1], spex_current [2]
 INPUTS:
   none

 OPTIONAL INPUTS:

    obj      - OSPEX object name, if not provided assumes old SPEX
   version   - string, version of the inversion code (currently only one version exist)
   order     - integer, regularization order. Can be 0 (default), 1, or 2.
   Npass     - integer, number of random noise realisations for the confidence strip.
                 Default is 30.
   Guess     - integer, 1 or 0 (default) - to use or NOT to use forward-fit in the constraint
   reg_tweak - float,  parameter to adjust the regularization parameter (default is 1).

 OUTPUTS:

 F(e)       - regularised photon spectrum, [photons/sec/cm^2/keV]
 dF         - 1 sigma error, [photons/sec/cm^2/keV]
 FWHM       - energy resolution of the regularised solution [keV]


 The results of the inversion are returned as a structure


 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   Version 1, eduard(at)astro.gla.ac.uk, 28 October, 2005
   31/10/05, obj reference added

 PROJECT:
   RHESSI/INVERSION

 NAME:
  inv_cross_section

 PURPOSE:

   Calculates cross-section matrix

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_cross_section,ee,eps,z,cs,de

 CALLS: ***
	Brm_BremCross
 INPUTS:

  ee   - array, mid-bin electron energy, keV
  de   - array, electron energy bin width, keV
 eps   - mid-bin count energy, keV
   z   - average number of electrons per H atom in solar corona

 OPTIONAL INPUTS:
   none

 OUTPUTS:

 cs   - cross-section matrix

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	inv_counts2electrons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:
   inv_get_data_spex

 PURPOSE:
   Grabs all data from OSPEX for inversion

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:
  inv_get_data_ospex

 CALLS: ***
	INV_GET_DATA_OSPEX, TIME2FILE
 INPUTS:

  obj - object name

 OPTIONAL INPUTS:
   none

 OUTPUTS:

   ee2N       - 2D array, electron energy bin edges
   ec2N       - 2D array, count energy bin edges
   counts     - count flux photons/kev/s/cm^2
   Ephoton    - photon errors photons/kev/s/cm^2
   drm_out    - spectral responce matrix
                counts/sec/keV/cm^2 /(photons/sec/keV/cm^2)
   time_inv   - string, time interval of the data
   efit_range - array of indexes, electron energies to invert

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	inv_counts2electrons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   Version 1, eduard(at)astro.gla.ac.uk, 30 July, 2005
   30 September, 2005 - time interval added

 PROJECT:
   RHESSI/INVERSION

 NAME:
   inv_get_data_spex

 PURPOSE:
   Grabs all data from SPEX for inversion

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:
  inv_get_data_spex

 CALLS: ***
	GETUTBASE [1], GETUTBASE [2], TIME2FILE, spex_current [1], spex_current [2]
 INPUTS:
   none

 OPTIONAL INPUTS:
   none

 OUTPUTS:

   ee       - photon energy bins 2D array
   eph      - count  energy bins 2D array
   Photon   - photon flux photons/kev/s/cm^2
   Ephoton  - photon errors photons/kev/s/cm^2
   drm_out  - Spectral Responce Matrix
              counts/sec/cm^2/keV/(photons/sec/cm^2/keV)
   time_inv - string, time interval of the data
   efit_range - range of acceptable output energies

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	inv_counts2electrons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   Version 1, eduard(at)astro.gla.ac.uk, 23 July, 2004
   30 September, 2005 - time interval added

 PROJECT:
   RHESSI/INVERSION

 NAME:
   inv_get_f_thin_ospex

 PURPOSE:
   Grabs all data from OSPEX for inversion

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:
  inv_get_f_thin_ospex,obj,ee,f_thin_model

 CALLS:
	none
 INPUTS:

   obj      - OSPEX object name
 efit_range - range of indexes for the inversion

 OPTIONAL INPUTS:
   none

 OUTPUTS:

   ee     - photon energy bins 2D array
   eph    - count  energy bins 2D array
   Photon - photon flux photons/kev/s/cm^2
   Ephoton- photon errors photons/kev/s/cm^2

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	inv_counts2electrons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 28 October, 2005
   Sa"m spotted the change in 'vth' function
   now allows three parameters from 'vth'
   (new parameter, iron abandance is not used)
    eduard  11/08/2006

 PROJECT:
   RHESSI/INVERSION

 NAME:
   inv_get_f_thin_spex

 PURPOSE:
   Grabs all data from SPEX for inversion

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:
  inv_get_f_thin_spex,ee,f_thin_model

 CALLS: ***
	F_VTH_THIN, spex_current [1], spex_current [2]
 INPUTS:
   none

 OPTIONAL INPUTS:
   none

 OUTPUTS:
   ee     - photon energy bins 2D array
   eph    - count  energy bins 2D array
   Photon - photon flux photons/kev/s/cm^2
   Ephoton- photon errors photons/kev/s/cm^2

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	inv_counts2electrons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:
  inv_gsvdcsq

 PURPOSE:
   To perform Generalised Singular Value Decomposition of two matrixes with
   double precision math


 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_gsvdcsq, A,B, alpha,betta,U,V,W

 CALLS: ***
	REVERSE
 INPUTS:

   A  - cross-section matrix
   B  - regularization matrix (should be square)

 OPTIONAL INPUTS:
   none

 OUTPUTS:

  Results of Generalised Singular Value Decomposition:

 A=U*SA*W^-1
 B=V*SB*W^-1

 where SA and SB are diagonal and SA^2+SB^2=1
 matrixes U and V are ortogonal e.g. U*U^T=U^T*U=1, V*V^T=V^T*V=1

   alpha  - diagonal elements of SA
   betta  - diagonal elements of SB
   U,V,W  - matrixes consisting of decomposition products

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	function_counts2photons, inv_counts2electrons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005
   20- Sept-2005: corrected SVDC routine output - re-ordering SValues and SVectors
   Note: SVDC produces non-decreasing singular values

 PROJECT:
   RHESSI/INVERSION

 NAME:
   inv_make_constraint

 PURPOSE:
   to make contraint matrix

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:
  inv_make_constraint,L,ee,de,fbar0,order

 CALLS:
	none
 INPUTS:
   ee    - array, middle bin energy
   de    - array, width of energy bins
   fbar0 - array, forward fit guess
   order - scalar, oder of regularization

 OPTIONAL INPUTS:
   none

 OUTPUTS:
    L -  constraint matrix

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	function_counts2photons, inv_counts2electrons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:
  second order regularization works somewhat worse than zero/first


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:
   inv_reg_parameter

 PURPOSE:
   to compute regularization parameter

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_reg_parameter,sigmaA,SigmaB,U,W,Data,Err,Fbar_fit,reg_tweak,opt

 CALLS:
	none
 INPUTS:
  SigmaA - vector, generalised singular values
  SigmaB - vector, generalised singular values
  U      - matrix, GSVD matrix
  W      - matrix, GSVD matrix
  Data   - vector, containing count flux
  Err    - vector, uncertanty on count flux
  Fbar_fit-vector, forward-fit for the electron distribution
 reg_tweak-scalar, parameter to adjusting regularization

 OPTIONAL INPUTS:
   none

 OUTPUTS:
    opt -  regularization parameter

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	function_counts2photons, inv_counts2electrons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005
   16- Sept-2005: now plots to display and eps files

 PROJECT:
   RHESSI/INVERSION

 NAME:
   inv_reg_resolution

 PURPOSE:
   Calculates resolution of regularised solution

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_reg_resolution,Alpha,Betta,opt,w,ee,de,FWHM

 CALLS:
	none
 INPUTS:

  Alpha  - vector, generalised singular values
  Betta  - vector, generalised singular values
  opt    - regularisation parameter
  w      - matrix, generalised singular value decomposition
  ee     - electron bin average energy, keV
  de     - electron bin width, keV

 OPTIONAL INPUTS:
   none

 OUTPUTS:
   FWHM -  resolution in keV defined as full width at half maximum
           of the resolution matrix

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 CALLED BY:
	function_counts2photons, inv_counts2electrons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 Sept, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:

   inv_reg_solution,sigmaA,SigmaB,U,W,data,opt,fbar_fit,reg_sol

 PURPOSE:

   calculates regulalarised solution

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_reg_solution,sigmaA,SigmaB,U,W,data,opt,fbar_fit,reg_sol

 CALLS: ***
	INV_REG_SOLUTION
 INPUTS:
  SigmaA - vector, generalised singular values
  SigmaB - vector, generalised singular values
  U      - matrix, GSVD matrix
  W      - matrix, GSVD matrix
  data   - vector, containing count flux
  opt    - scalar, regularization parameter
  Fbar_fit-vector, electron flux taken from forward-fit

 OPTIONAL INPUTS:
   none

 OUTPUTS:
   reg_sol -  regularization parameter

 OPTIONAL OUTPUTS:
   none

 KEYWORDS:
   none

 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:


 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 16 Sept, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:

  inv_save_electrons

 PURPOSE:

   The routines saves and plots main results of the regularization

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_save_electrons,ee,e_c,reg_sol,reg_sol_err,FWHM,f_thin,counts,ecounts,ph_reg,sol_file,sol_ps

 CALLS: ***
	PLOTERROR
 INPUTS:

   ee   - vector, electron middle bin energy
   e_c  - vector, count middle bin energy
 reg_sol- vector, regularised solution
 reg_sol_err - vector, 1 sigma errors for regularised solution
  FWHM       - vector, energy resolution of the regularised solution
  f_thin     - vector, forward-fit
  counts     - vector, input count flux
  ecounts    - vector, 1 sigma uncertanties for count flux
  ph_reg     - vector, regularised count flux
 sol_file    - string, output data filename
 sol_ps      - string, PS plot filename


 OPTIONAL INPUTS:

 OUTPUTS:

  IDL save file with the results
  PS file with the results

 KEYWORDS:
   none

 CALLED BY:
	inv_counts2electrons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:

 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:

  inv_save_electrons

 PURPOSE:

   The routines saves and plots main results of the regularization

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_save_electrons,ee,e_c,reg_sol,reg_sol_err,FWHM,f_thin,counts,ecounts,ph_reg,sol_file,sol_ps

 CALLS:
	none
 INPUTS:

   ee   - vector, electron middle bin energy
   e_c  - vector, count middle bin energy
 reg_sol- vector, regularised solution
 reg_sol_err - vector, 1 sigma errors for regularised solution
  FWHM       - vector, energy resolution of the regularised solution
  f_thin     - vector, forward-fit
  counts     - vector, input count flux
  ecounts    - vector, 1 sigma uncertanties for count flux
  ph_reg     - vector, regularised count flux
 sol_file    - string, output data filename
 sol_ps      - string, PS plot filename


 OPTIONAL INPUTS:

 OUTPUTS:

  IDL save file with the results
  PS file with the results

 KEYWORDS:
   none

 CALLED BY:
	inv_counts2electrons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:

 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005

 PROJECT:
   RHESSI/INVERSION

 NAME:

  inv_save_photons

 PURPOSE:

   The routines saves and plots main results of the regularization

 CATEGORY:
   HESSI, Spectra, Inversion

 CALLING SEQUENCE:

  inv_save_photons,ee,e_c,reg_sol,reg_sol_err,FWHM,ph_thin,counts,ecounts,ph_reg,sol_file,sol_ps

 CALLS: ***
	PLOTERROR
 INPUTS:

   ee   - vector, electron middle bin energy
   e_c  - vector, count middle bin energy
 reg_sol- vector, regularised solution
 reg_sol_err - vector, 1 sigma errors for regularised solution
  FWHM       - vector, energy resolution of the regularised solution
  f_thin     - vector, forward-fit
  counts     - vector, input count flux
  ecounts    - vector, 1 sigma uncertanties for count flux
  ph_reg     - vector, regularised count flux
 sol_file    - string, output data filename
 sol_ps      - string, PS plot filename


 OPTIONAL INPUTS:

 OUTPUTS:

  IDL save file with the results
  PS file with the results

 KEYWORDS:
   none

 CALLED BY:
	function_counts2photons, inv_counts2photons
 COMMON BLOCKS:
   none

 SIDE EFFECTS:


 RESTRICTIONS:

 MODIFICATION HISTORY:
   eduard(at)astro.gla.ac.uk, 23 May, 2005

 PROJECT:  CHIANTI

       CHIANTI is an Atomic Database Package for Spectroscopic Diagnostics of
       Astrophysical Plasmas. It is a collaborative project involving the Naval
       Research Laboratory (USA), the University of Florence (Italy), the
       University of Cambridge and the Rutherford Appleton Laboratory (UK). 

 NAME:
	ion2filename

 PURPOSE:
	Ion names as character strings are converted to
	provide their complete file name (with out suffix)

 CATEGORY:
	
	naming utility

 CALLING SEQUENCE:

       ION@FILENAME,Ion,Filename


 INPUTS:
	Name:   such as 'c_2'


 OUTPUTS:

	Filename:  !xuvtop/c/c_2/c_2


 CALLS: ***
	CONCAT_DIR [1], CONCAT_DIR [2], CONCAT_DIR [3], concat_dir [4]
 CALLED BY:
	PLOT_POPULATIONS, SETUP_ION
 EXAMPLE:

                     > ion2filename,'c_2d',filename
                     > print,filename
                     > !xuvtop/c/c_2d/c_2d

 MODIFICATION HISTORY:

 	Written by:	Ken Dere

	V.2,  September 1999:  added for use with Version 3

       V.3, 21-May-2002, Giulio Del Zanna (GDZ) 
                   generalized directory concatenation to work for
                   Unix, Windows  and VMS. 

 VERSION     :   3, 21-May-2002 

 PROJECT:  CHIANTI

       CHIANTI is an Atomic Database Package for Spectroscopic Diagnostics of
       Astrophysical Plasmas. It is a collaborative project involving the Naval
       Research Laboratory (USA), the University of Florence (Italy), the
       University of Cambridge and the Rutherford Appleton Laboratory (UK). 


 NAME:
	ION2SPECTROSCOPIC

 PURPOSE:

	provide identification string

 CATEGORY:

	database.

 CALLING SEQUENCE:

       ION2SPECTROSCOPIC, Ion, Spectroscopic

 INPUTS:

       Ion:   CHIANTI notation for an ion, i.e., 'c_2' for C II	

 OUTPUTS:

	Name:  the spectroscopic notation for the ion, i.e. 'C II'

 CALLS: ***
	STR_SEP
 CALLED BY:
	CH_SYNTHETIC, DENSITY_RATIOS, GOFNT, PLOT_POPULATIONS, POP_SOLVER
	TEMPERATURE_RATIOS, bb_rad_loss, ch_ss, get_contributions
 EXAMPLE:
             > ion2spectroscopic,'fe_13',name
             > print,name
             > Fe XIII   

             > ion2spectroscopic,'o_6d',name
             > print,name
             > O VI d   

 MODIFICATION HISTORY:
 	Written by:	    Ken Dere
	September 1999:     Version 3.0

       Ver.2, 11-Dec-2001, Peter Young
           Revised routine; removed call to repstr

       V.3, 29-May-2002, Giulio Del Zanna (GDZ) 
              Added output keyword dielectronic.

       V.4, 12-Aug-02, GDZ 
           Corrected a typo concerning XXII.

 VERSION     :   4, 12-Aug-02

 NAME:

   ION_FRAC_INTERP

 PROJECT

   CHIANTI

 EXPLANATION

   Performs interpolation of an ion fraction array (such as contained in
   the CHIANTI .ioneq files) to yield ion fractions at temperatures TEMP.

   Note that the ion must already have been selected before calling this
   routine, since IONEQ_FRAC is a 1D array. The routine GET_IEQ is an
   alternative if the ion has not been selected.

 INPUTS

   TEMP        Temperature(s) for which ion fractions are required. 
               Units: K.

   IONEQ_LOGT  Log (base 10) of temperature (units: K). A 1D array of
               temperatures for which the ion fraction is defined.

   IONEQ_FRAC  A 1D array of ion fractions at the temperatures defined by
               ioneq_logt

 OUTPUT

   The ion fraction defined at the temperatures TEMP. If values of TEMP lie
   outside the range of the ion fraction or the range of IONEQ_LOGT, then
   values of 0 are returned at these temperatures.

 HISTORY

   Ver.1, 10-Jun-2005, Peter Young
 CALLED BY
	CORRECT_POPS

 EXPLANATION:

	When accessing ionisation balance data from the CHIANTI database, it 
	is output at log temperature values from 4 to 8 at 0.1 intervals. 
	For display purposes it is often nice to perform spline interpolation 
	to give a smoother function. This interpolation should be performed 
	on the logarithm of the data as this is more slowly varying.

	This routine performs such an interpolation. It is only essential to 
	input G_T and N. Specifying T is optional (see below), while TI and 
	G_TI are output. N gives the number of points within an interval over 
	which interpolation is performed.

 INPUTS:

	G_T:	Data for which interpolation required

 OPTIONAL INPUTS:

	T:	Values at which is G_T is tabulated. If not specified, then 
		taken as 4 to 8 in 0.1 intervals.
	N:	Specifies `smoothness' of fit. E.g., N=5 means that single 
		intervals are divided into 5 intervals.
	TI:	If some temperatures are specified, then the SPLINE call is 
		used to work out the values of G_TI that correspond to these 
		temperatures. Only works if N is not specified.

 OUTPUTS

	T:	If not specified, then output as an array from 4 to 8 in 0.1 
		intervals
	TI:	Interpolated T values. If the TI are specified on the command 
		line, then these values are returned. 
	G_TI:	Interpolated G_T values

 KEYWORDS

	PLOT -	The interpolated data is displayed together with the original 
		data.

 EXAMPLE:

	g_t=g_of_t(26,13,/ray)
	ion_interp,t,g_t,ti,g_ti,5,/plot
	plot,t,g_t,psym=2,xra=[5.8,6.7]
	oplot,ti,g_ti

	ion_interp,t,g_t,[6.112,6.254],g_ti,/plot

 CALLS: ***
	SPLINE
 HISTORY:

	Ver 1, PRY 17-JUN-98
	Ver 2, PRY 10-AUG-98, corrected minor bug
	Ver 3, PRY 22-SEP-98, corrected interpolation error
	Ver 4, PRY 3-MAR-99,  now allows TI to be specified

 CONTACT:

	Peter Young, Cambridge University (P.R.Young@damtp.cam.ac.uk)

 NAME:
	ISNUM
 PURPOSE:
	To tell you if a variable is numeric or not
 CALLING SEQUENCE:
	if isnum(a) then ...
 INPUTS:
	a - the variable to check
 RETURNS:
	a boolean
 KEYWORDS:
	real - if set, require that "a" lie on the real number line.
 AUTHOR:
	Craig DeForest
 CALLS: ***
	data_chk [1], data_chk [2]
 CALLED BY:
	V4, v4canon
 HISTORY:
	Original implementation: 9-Oct-97

 NAME:

       ISOTHERMAL

 PURPOSE:
       Computes spectra from isothermal plasmas. A number of isothermal 
       plasmas can be included.
       Note that this routine has a number of unique features that 
       distinguish it from the other CHIANTI synthetic spectra routines. 
       See the Programming Notes section.

 INPUTS:

       WMIN      Minimum of desired wavelength range in Angstroms.

       WMAX      Maximum of desired wavelength range in Angstroms.

       WAVESTEP  Bin size of spectrum (in Angstroms)

       TEMP      Electron temperature (or array).

 OPTIONAL INPUTS

       PRESSURE  Electron pressure in units of cm^-3 K.

       EDENSITY  Electron density in units of cm^-3.

       EM        Emission measure. The units of EM govern the intensity 
                 units of the emission lines (i.e., column or volume 
                 emission measure units). If EM is not specified, then the 
                 emission measure is set to (N_e * N_H) where N_e is 
                 derived from the user-specified PRESSURE or EDENSITY, 
                 and N_H is derived from the routine PROTON_DENS.PRO.

       SNGL_ION  Rather than include the entire list of CHIANTI ions in 
                 the calculation, this input can be used to select a 
                 single ion, or a number of different ions. E.g., 
                 SNGL_ION='s_2' or SNGL_ION=['s_2','s_3','s_4'].

       RADTEMP   The blackbody radiation field temperature (default 6000 K).

       RPHOT    Distance from the centre of the star in stellar radius units.
                I.e., RPHOT=1 corresponds to the star's surface. (Default is
                infinity, i.e., no photoexcitation.)

       MASTERLIST  The list of ions that will be considered for the 
                   spectrum is contained in the masterlist file in the 
                   CHIANTI directories. The user can specify his own file 
                   through this keyword. E.g., 
                   masterlist='/user/home/masterlist.ions'


	ABUND_NAME:  Name of the abundance file to use.  If not passed, then
		     the user is prompted for it.

	IONEQ_NAME:  Name of the ionization equilization name to use.  If not
		     passed, then the user is prompted for it.


  KEYWORDS

       NOPROT     Switch off the inclusion of proton rates in the level 
                  balance.

       ERGS       The units of the output spectrum are by default in photons. 
                  Setting /ERGS switches to erg units.

       CONT       Adds continuum (free-free, free-bound, two-photon) to 
                  spectrum.
  
       ALL        Include all lines, i.e. also those for which wavelengths 
                  are only theoretical and not observed. 

  OUTPUTS:

        LAMBDA   Wavelength array of calculated synthetic spectrum.

        SPECTRUM Intensity array. The units depend on the user inputs to 
                 ISOTHERMAL -- see note below. 

        LIST_WVL A list of wavelengths for use with synthetic_plot.pro

        LIST_IDENT A list of line identifications for use with 
                   synthetic_plot.pro

 PROGRAMMING NOTES

        Intensity Units
        ---------------
        The units are of the form photons cm^3 s^-1 sr^-1 * (units of EM), 
        changing to ergs if the /ergs keyword is set.

        The volume emission measure (N_e*N_H*V) has units cm^-3.

        The column emission measure (N_e*N_H*h) has units cm^-5.


        Unique features
        ---------------
        The emission lines in the final spectrum have no width and thus 
        each occupies a single pixel of the spectrum. The size of the 
        pixels are set by WAVESTEP.

        As stated above, the units of the output spectrum are 
        photons cm^3 s^-1 sr^-1, i.e., there is no "per angstrom" term. 
        This means that (i) the height of the emission lines in the 
        spectrum does not change with varying WAVESTEP, and (ii) the height
        of continuum does change with WAVESTEP.

 COMMON BLOCKS

        ELEMENTS

 CALLS

        CH_SYNTHETIC, READ_ABUND, CH_GET_FILE, CONCAT_DIR, FREEFREE, 
        FREEBOUND, TWO_PHOTON

 HISTORY
        Ver.1, 8-Apr-02, Peter Young  Rutherford Appleton Laboratory,
        p.r.young@rl.ac.uk 
        Tries to replicate the behaviour of the original ISOTHERMAL which 
        was found in earlier versions of CHIANTI (v.3 and earlier). 

 MODIFICATION HISTORY

       Ver. 2, Giulio Del Zanna (GDZ), 28-Apr-02 
               Added abund_name,ioneq_name keywords.
               Also, added photons keyword in call to MAKE_CHIANTI_SPEC.

       Ver. 3, Peter Young, 24-May-02
                 Modified to produce arrays of spectra when an array of 
                 temperatures is given

       V.4, GDZ, 28-May-02 
              Added a couple of checks on file existence and modified the call
              to ch_synthetic and make_chianti_spec  due to change of keyword
              names.  

       V.5, Peter Young, 16-Jul-02
              Restructured routine to avoid crashes when a large number of 
              temperatures is input.

       V.6, 8-Aug-02 GDZ
              Added one error checking

       V.7, 18-Aug-03, Peter Young
              Added EM= keyword.
 
       V.8, 14-Sept-2005 GDZ 
              Added ALL keyword and modified header, error message.

       V.9, 3-Oct-2005, GDZ
              Now the FOR loop accepts more than 32000 lines.


 VERSION     : 
       Version 9, 3-Oct-2005
        
 CALLS:
 CALLED BY
	moffat2d, trace_psf_isothermal

 NAME:
	ISVALID
 PURPOSE:
	Returns validity flag for its argument
 CALLING SEQUENCE:
	result = isvalid(variable)
 INPUTS:
	variable: the variable to be tested
 OPTIONAL INPUT PARAMETERS:
	(none)
 KEYWORD PARAMETERS:
	(none)
 CALLED BY:
	CALC_LOI_ROLL, COORD [2], COORD [3], DISPLOI_MON5K, FIELDLINE, FOT_ROLL, GETV4TYPE
	MAKE_DIPOLES, MAKE_SYNOP, PIX2V4, PLOT_PTLIST, ROLL_PLOT, SUNEARTHDIST, V4, V42PIX
	V4DIFF_ROT, V4HELP, V4MCART, V4MSPH, V4PRINT, V4UNITS, V4XCARR2HEL, V4XCART2SPH
	V4XHEL2CARR, V4XS2SC, V4XS2SRS [1], V4XSC2HC [1], V4XSC2HC [2], V4XSC2HEC, V4XSC2S
	V4XSPH2CART, V4_RESOLVE_XFORM, ZCLIP, ZCONTAINS, ZDEGR, ZDEROTATE, ZGETPLUME, ZGRID
	ZHOVER, ZMKHDR, ZPAD, ZPRINTSUN, ZUNPAD, cartdist, cube_interp, datify, disp_sci160k [1]
	disp_sci160k [2], dpcstr [1], dpcstr [2], equalize_rasters, find_launchpoints
	fixinate_eit, fixinate_lasco, fixinate_trace, getct, hao_hdr, id_esc, id_unesc
	local_mag_extrap, make_grid_sphere, mdialign, mon_sci5k, plot_loi_mmad, radial_bkg
	redo_disploi, redo_mon_sci5k, struct_eq, trace_field, unpack_trace, wmatch, zaspect
	zbytscl, zcorralign, zcurs_ok, zd4, zdeheliographinize, zdiff_rot, zhelio2xy
	zheliographinize, zintervals, zmagoverlay, zmatch, zmontage, zmovie, zmovify
	zmovinate, zpb0r [1], zpb0r [2], zscale, zsi, zstructify, ztrack, zunits, zunspike
	zunwrap, zxy2helio
 RESTRICTIONS:
	None I know of....
 MODIFICATION HISTORY:
	Created by Craig DeForest, 4/13/1995

 PROJECT:  CHIANTI

       CHIANTI is an Atomic Database Package for Spectroscopic Diagnostics of
       Astrophysical Plasmas. It is a collaborative project involving the Naval
       Research Laboratory (USA), the University of Florence (Italy), the
       University of Cambridge and the Rutherford Appleton Laboratory (UK). 

 NAME

    ITOH

 EXPLANATION

    Calculates the relativistic free-free continuum using the fitting 
    formula of Itoh et al. (ApJS 128, 125, 2000).

 INPUTS

    TEMP    Temperature (in K).

    WVL     Wavelengths in angstroms. Can be a scalar or vector. If /keV is
            set, then WVL is assumed to contain energies in keV units.

 OUTPUTS

    INT     Free-free continuum emissivity in units of 
            10^-40 erg cm^3 / s / sr / Angstrom per unit emission 
            measure [ integral(N_e N_H dh) in cm^-5 ]. If T is given as 
            a 1-D array, then RAD will be output as a 2-D array, 
            with one element for each temperature and wavelength 
            (but also see SUMT).

            If the keyword /keV is set, then the units of INT will be 
            10^-40 erg cm^3/s/sr/keV

 OPTIONAL INPUTS

    DEM_INT An array of same length as TEMP which contains the 
            differential emission measure values at each temperature. 
            The emissivity at each temperature is multiplied by the 
            DEM value and the d(logT) value.

    MIN_ABUND This keyword allows the specification of a minimum abundance, 
              such that any elements with an abundance (relative to 
              hydrogen) less than MIN_ABUND will not be included in the 
              calculation. E.g., MIN_ABUND=1e-5.

 KEYWORDS

    NO_SETUP By default the routine asks the user which ion balance 
             and abundance files to use via pop-up widgets. If 
             /no_setup is used then this data is taken from the common 
             block.

    SUMT     The default is to output the intensity array as an array 
             of size (nwvl x nT). Setting this keyword performs a sum 
             over the temperatures to yield a vector of same size as 
             the input wavelengths, thus producing the complete 
             free-free spectrum.

    PHOTONS  Gives output emissivity in photon units rather than ergs.

    KEV      If set, then WVL is assumed to contain energies in keV units
             rather than wavelengths in Angstroms.

 CALLS

    SETUP_ELEMENTS

 PROGRAMMING NOTES

    In the Itoh et al. paper they state that their fitting formula is 
    valid for ion charges (Z_j) of 1-28. The data-file they provide 
    actually goes up to Z_j=30, and so you will see that the loop over 
    z (see below) goes up to 30.

    There is no restriction on the elements for which the fitting 
    formula is valid, and so all elements are allowed to be included 
    (subject to their abundances being non-zero).

 HISTORY

    Ver.1, 3-Dec-2001, Peter Young

    Ver.2, 22-May-2002, Peter Young
            Added MIN_ABUND optional input.

    Ver.3, 28-May-2002, Peter Young
            Corrected way in which DEM is handled.

    Ver.4, 9-Mar-2006, Peter Young
            Added /keV keyword.
 CALLS:
 CALLED BY
	freefree

 NAME:
	IXCOM
 PURPOSE
 	For calling the FORTRAN program XCOM to calculate photon cross
 	sections and plot various parameters.
 	Calls the FORTRAN routine IXCOMN through CALL_EXTERNAL.  IXCOMN  calls
 	XCOM if the XCOM command is given. , Then calls plotting routine XPLOT

 CATEGORY: HESI, GEN

 CALLING SEQUENCE:  Ixcom, x=X,dens=xdens,subst=Csubst

 CALLS: ***
	SETLOG, XPLOT
 INPUTS:
       none 

 OPTIONAL INPUTS:
       none

 OUTPUTS:
       see keywords

 OPTIONAL OUTPUTS:
       none

 KEYWORDS:
       OUTPUT:
	 X=x, The array of attenuation coefficients (see HESI_MENU help,
	or Xcom documentation (XCOM is a fortran program, look in xcom_code)
	Dens=xDens, output the density of the substance
	subst=Csubst, ouput the string name of the Substance
 CALLED BY:
	HESI_MENU, PROCESS_XCOM_GD
 COMMON BLOCKS:
       none

 SIDE EFFECTS:
       none

 RESTRICTIONS:
	You *MUST* have the FORTRAN Code, define the system logical
	xcom_code to be the directory containing FORTRAN code

       Never tested on a UNIX implementation of IDL or FORTRAN, 
    	Tested up to DEC Alpha VMS 6.2.  There will most
	likely be problems with calling the element data files in UNIX!
	If there is a demand, the GSFC SDAC may be able to port the code

 PROCEDURE:
       Call this procedure standalone or use HESI_MENU

 MODIFICATION HISTORY

 Written by Eric Carzon  1992
 Major modifications KT April 94
 EAC modifications for Brian Dennis, 12/94
 include Fractional Attenuation from i
 incident beam (1 - fractional transmission)
 as a plot option
  allowed use of a grid (works best in log, log) for minor
 tick marks (ie a logarithmic, base 10, grid to find points
 on the plot)
 set automatic densities for elements
 fixed ability to enter compounds 

 EC finished modifications in Feb. 95, including density and substance
 output only keywords for use with HESI proposal graphics software
 EC 6/10/96, header documentation