// return max diameter of any particle

  // not used in granular neighbor calculation since particles have radius

  // but will insure cutoff is big enough for any other neighbor lists built

  // if no particles, return 1.0

  double *radius = atom->radius;

  int nlocal = atom->nlocal;

  double maxrad = 0.0;

  for (int m = 0; m < nlocal; m++) maxrad = MAX(maxrad,radius[m]);

  double mine = maxrad;

  MPI_Allreduce(&mine,&maxrad,1,MPI_DOUBLE,MPI_MAX,world);

  double mine = 2.0*maxrad;

  return 2.0*maxrad;

  double maxdiam;

  MPI_Allreduce(&mine,&maxdiam,1,MPI_DOUBLE,MPI_MAX,world);

  if (maxdiam == 0.0) maxdiam = 1.0;

  return maxdiam;

}

/* ----------------------------------------------------------------------