********************
for the   idl_calc   subdirectory 

There are four .dat ascii files
  directory.dat      
  indices.dat  
  work.dat
  compare_spectra.dat

In the   directory.dat   ascii file:
Specify the subdirectory which has the netCDF input refractive indices files
Specify the subdirectory to which output text and ps files are written to
The subdirectories are one level down from the directory that contains
the .pro's and the .dat files.

The   indices.dat   ascii file lists the refractive index files (leave as is)
The listing is coordinated with the  rdindices.pro  routine which reads in
a specific set of indices

The  compare_spectra.dat  ascii file in the compare_spectra subdirectory
specifies which spectra files to intercompare (the user places ascii files of
calculations and/or observed extinction spectra in this subdirectory)

The   work.dat   ascii file specifies the work to be done.
EDIT this file to specify the specific work to be done.
Generally, integer flags are set to 1 to do something, 0 to not do something.
See the   example   subdirectory for an example of the work.dat file and the output
produced by the program

itest      Specify itest=1 in work.dat if a test case is to be calculated.

icompare   Specify icompare=1 if you compare (graph) two sets of indices.

imultisets To graph the indices from several sets of indices put imultisets=1
           This is done after the user runs the program for the desired sets of indices
           and places the output ascii files in the multisets subdirectory
           See the comments in multisetsgraph.pro for details

Normally, itest=0, icompare=0, imultisets=0

iset       For the main calculation, specify which index set is used
           The iset value corresponds to one of the sets listed in the
           indices.dat   ascii file. The indices.dat file and rdindices.pro
           routine will change as more indices are incorporated into the
           IDL program.
igraphi    If=1 will graph the indices of refraction (original set and
           those interpolated to the specified output scale).

iwave      If=1 will use an output wavenumber scale.
           If=2 will use an output wavelength scale.
w1,w2,dw   The range of wavenumber (or wavelength) and point spacing.

The size distribution is a log-normal size distribution with 2 modes 
den1,rad1,sig1    total number (#/cm3), mean radius (microns), distribution width 
den2,rad2,sig2    total number (#/cm3), mean radius (microns), distributiion width 
Note that alog(sig1) and alog(sig2) are used in the log-normal distributions, so
the input sig1 is e.g. 2.3 

igraphd    If=1 will graph the size distribution used in the calculation.

igraphe    To graph the extinction, scattering, absorption, asymmetry, and
           single scattering albedo spectra put igraphe=1

Other print flags allows one to write out the details from the various
parts of the code, and write out ascii and netCDF files of the output
from the code.

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To run the idl program, type in    idl   on the command line
> idl
folowed by 
>.r main

The program will ask you some information (the specifics depend upon on which
refractive index set you work with). The program prints out to the screen (e.g. 
tells you the path names of various ps graphics, ascii and netCDF data files
that are created by the program)

A variety of ps files (for the indices, size distribution, and spectra of extinction, scattering,
absorption, single scattering albedo, and asymmetry parameter) and ascii files of these 
quantities are sent to the    output  subdirectory.
The ps (postscript graphics files) can be viewed on the user's laptop by the    gv   command
(type gv followed by the name of the ps file)

The   f.out   ascii file (in the idl_calc subdirectory from which you run the program) also contains the results
of the calcilation.

An example (using the Deguine volcanic ash indices, published in 2020) is given in the example subdirectory

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Please do send comments on program bugs, and suggestions on ways to improve and
enhance the program.

********************
Best regards,
Steven Massie
Laboratory for Atmospheric and Space Physics
University of Colorado 
Boulder, Colorado
Steven.Massie@lasp.colorado.edu
1-303-735-6583
