********************
The   fortran_ascii  program

There are three .dat ascii files
  directory.dat      
  indices.dat  
  work.dat

In the   directory.dat   ascii file:
Specify the subdirectory which has the ascii input refractive index files
Specify the subdirectory to which output text files are written to

The   indices.dat   ascii file lists the refractive index files (leave as is)
The listing is coordinated with the  rdindices.f90  routine 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

itest      Specify itest=0 in work.dat  (test cases are not done in the fortran program)

icompare   Specify icompare=0, the fortran program does not do graphs

imix       Specify imix=0 (will not compare mixing rules in the fortran program)

Normally, itest=0, icompare=a, imix=0 in the fortran program0

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 program

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 

********************
The fortran f.90 program

The user will need to edit the   Makefile   to specify the compiler that
is to be used

For the version I applied, I had these lines in the Makefile

SET2= -L/usr/lib/gcc/x86_64-redhat-linux/4.8.5/
SET3= -L/usr/pgi/linux86-64/14.9/lib/ -lgfortran
prg: $(SRCS)
        gfortran $(FFLAGS) -o prg $(SRCS)  -L/usr/local/lib  \
        $(SET2) $(SET3)

The command line       
> make

produces the   prg*   executable

Next, edit the   work.dat   file

********************
To run the fortran program type
>./prg

The fortran program does not output graphics files or netCDF files

The calculated spectra are given in the   f.out   ascii file and the 
  ext.ascii  indices_interp.ascii  indices_orig.ascii  size.ascii
files also written to the directory from which the fortran_ascii program is run from. 

An example (for the use of the 2020 Deguine volcanic ash indices) is given in the example subdirectory

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