Hi!
I'm manteining the LIGGGHTS PKGBUILD in AUR. Any doubt, compilation error or suggestion you can make it right here.
You must to install liggghts and liggghts-lpp (Pizza.py) from AUR.
it's you use yaourt, it's enough with:
yaourt -S liggghts-lpp
And you will get the liggghts, pizza and lpp command in /usr/bin