1. compile:
   edit PATH TO PPN CODE DIR (PCD) in Makefile, default ok in example dir
   
   clean: `make distclean` ( only necessary if you made changes to
                            INDEX_REACLIB or NNN)
   make: `make`

2. run: `./ppn.exe'

Content of this directory:

ppn_frame.input			These are the input decks for the three 
ppn_physics.input		packages, frame, physics and solver.
ppn_solver.input

isotopedatabase.txt		standard species file
README				this file 
Makefile                        Makefile for the code
trajectory.input		these trajectories can be written with the 
				ascii_table.py module
python-scripts			several python plot scripts that produce 
				meaningful visuals of this run, run either as 
				'python script.py' or within an 
				ipython --pylab session via 'ed scipt.py' for
				an interactive experience (you may want to turn
				on the 'show' option in some of the plot 
				commands)
p20.dat				the initial abundance file