The LES functionality for sander and gibbs was written by Carlos Simmerling,
based on his thesis work and the experiences of the Elber group. It basically
functions by modifying the prmtop file using the program addles.
The modified prmtop file is then used with a slightly modified version
of sander called sander.LES.
Information on using addles for sander.LES is given here. The gibbs
version is not yet ready.