This is GenX, which is a X-ray and Neutron reflectivity fitting program and originally written by Matts Björck, ported to Python 3 and wxPython Phoenix by me. Codes that were originally dependent on scipy.weave were re-written in Cython. Some caveats of this version include the following:

1. I have only tested on GNU/Linux, however there is no reason why it will not work on other platforms. The code itself should be platform-neutral, and only setup.py needs to be modified in order to install the program on other platforms.
2. While this Python 3 version can open both the .gx and .hgx files saved by the Python 2 version, it can not save the .gx files due to the change in the Python pickle protocol. I have changed the extension of the saved files from .gx to .gx3 to highlight this incompatibility. If interoperability with the Python 2 version is desired, please use .hgx format.

Apart from the save file caveat mentioned above, this version is compatible with both Python 2 and Python 3, provided wxPython Phoenix is installed. To install this program, please run either sudo python2 setup.py install or sudo python3 setup.py install, depending on the Python version. A PKGBUILD for Arch Linux can be found from the AUR.