Write the input/data files and run LAMMPS.

def run(self):
        """
        Write the input/data files and run LAMMPS.
        """
        lammps_cmd = self.lammps_bin + ['-in', self.input_filename]
        print("Running: {}".format(" ".join(lammps_cmd)))
        p = Popen(lammps_cmd, stdout=PIPE, stderr=PIPE)
        (stdout, stderr) = p.communicate()
        return stdout, stderr