add consistent 'particle overflow' error for serial

    delete [] allnlattpts;

    delete [] allnboxmes;

    delete [] cumsum_lattpts;

  } else nboxme = ninsert;

  } else {

    if (ninsert > nlattpts)

       error->one(FLERR,"Attempting to insert more particles than available lattice points");

    nboxme = ninsert;

  }

 // probably faster to have individual processors 're-choose' their random points

  // Nmask will be used to indicate which lattice points to insert