Lumen is a GPL code derived from Yambo 4.1.2

Quick installation instructions for the impatient:
   ./configure [options]
   make all

All the material included in this distribution is free software;
you can redistribute it and/or modify it under the terms of the GNU
General Public License as published by the Free Software Foundation;
either version 2 of the License, or (at your option) any later version.

These programs are distributed in the hope that they will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
for more details (see COPYING file).