The Python program in the python_calc subdirectory

********************
There are three .dat ascii files in the 
  directory.dat      
  indices.dat  
  work.dat

In the   directory.dat   ascii file:
Specify the subdirectories which have the ascii input refractive index files

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

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

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

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 

********************
To run the Python program type
./ri_main.py

An extinction spectrum should appear on the screen (provided you have a graphics application
installed on your laprop, and you have access to the python matplotlib). 
The png of what's shown is in the output    ext.png   file 

I had the freeware Xming application installed on my laptop.
See  https://sourceforge.net/projects/xming/

To not do the graph, set   igraph=0   in   calc_ext.py
since calc_ext.py has these lines of code after igraph=1 is specificed
        import matplotlib
        import matplotlib.pyplot as plt

The   f.out   ascii output file (in the subdirectory from which you run the Python code) has the extinction,
scattering, absorption, single scattering albedo, and asymmetry parameter spectra.

An example (for the use of the 2020 Deguine volcanic ash indices) is given in the example subdirectory
cp the work.dat file to the subdirectory which has the .py modules.

********************
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
