Free-electron Laser Dynamics

    This program studies the nonlinear electron-wave interaction inside
a Free-electron Laser. The computed gain is plotted against the longitudinal
electric field amplitude to show the saturation process. Each data point
on this curve is computed by a node in HeNCE.
    Key files:
	engLost.c --- all the physics is in this function
	fel.gr --- the HeNCE graph
	cost.mat --- the cost matrix

    One problem with HeNCE is it doesn't link to the math library
automatically. So one must edit the Makefile manually to add the C compiler
option "-lm".         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    The output data are written to the file "hdata" in the user's *home*
directory (HeNCE---PVM, more precisely---runs the user's programs from
the home directory. Although it knows about the current working directory
it does not pass that to the user program.) The data can be plotted with
the command
	xgraph < hdata
