FEPX is distributed as a free / open-source software, under the terms of the GNU General Public License (GPL). In short, this means that everyone is free to use FEPX and to redistribute it on a free basis. FEPX is not in the public domain; it is copyrighted and there are restrictions on its distribution (see the license and the related FAQ).
It you use FEPX for your own work, please mention it explicitly and cite one or several of the papers given in the References section below. The papers are available for download.
Current official release¶
P.R. Dawson and D.E. Boyce, FEPX - Finite Element Polycrystals: Theory, Finite Element Formulation, Numerical Implementation and Illustrative Examples, arXiv:1504.03296: link