Jim, Thanks for including the relevant section from the documents. We typically do a standard install of software, so wouldn't have added this module. I'll look at building LAMPPS with this added, and will also check for a newer version of LAMMPS at the same time. Dave ________________________________________ From: Research Computing Support [[log in to unmask]] On Behalf Of Moller, James C. Dr. [[log in to unmask]] Sent: Friday, July 08, 2011 2:19 PM To: [log in to unmask] Subject: Peridynamics availability in LAMMPS Hello, I am trying to run the example /software/lamps/lamps-7Mar10/examples/peri/in.peri The resulting message is that the specified atom type (peri) was invalid. This leads me wonder whether the make run included “turning on” the peridynamics functionality. Below is what I found in the Peridynamics guide. Thanks, Jim Moller 2.1 Building the Peridynamic Module within LAMMPS In the LAMMPS distribution, the peridynamic model is distributed as an add-on module, which means that it is not by default compiled with the rest of LAMMPS. To instruct LAMMPS to build the peridynamic module, go to the LAMMPS source subdirectory (/src) and type make yes-peri followed by make <your platform> to compile LAMMPS on your particular platform.