Running this example requires that LAMMPS be built with the VORONOI package and its compute voronoi command. The compute uses the Voro++ library, freely available at http://math.lbl.gov/voro++, to compute the Voronoi tesselation locally on each processor. Voro++ was developed by Chris H. Rycroft while at UC Berkeley / Lawrence Berkeley Laboratory. See the lib/voronoi/README file for instructions on how to download and install the Voro++ library for use with LAMMPS.