atom->create_avec(old->atom_style,nstyles,keywords);

  // check that new problem size will not be too large

  // if N > 2^31, turn off tags

  // if N > 2^31, turn off tags for existing and new atoms

  // if molecular, N/Nbonds/etc cannot be > 2^31 else tags/counts invalid

  double rep = nrep;

  if (rep*old->natoms > MAXATOMS) atom->tag_enable = 0;

  if (atom->tag_enable == 0)

    for (int i = 0; i < atom->nlocal; i++)

      atom->tag[i] = 0;

  if (atom->molecular) {

    if (rep*old->natoms > MAXATOMS || rep*old->nbonds > MAXATOMS ||

	rep*old->nangles > MAXATOMS || rep*old->ndihedrals > MAXATOMS ||