// print stats for changed group

  int n,all;

  int n;

  n = 0;

  for (i = 0; i < nlocal; i++) if (mask[i] & bit) n++;

  MPI_Allreduce(&n,&all,1,MPI_INT,MPI_SUM,world);

  double rlocal = n;

  double all;

  MPI_Allreduce(&rlocal,&all,1,MPI_DOUBLE,MPI_SUM,world);

  if (me == 0) {

    if (screen) fprintf(screen,"%d atoms in group %s\n",all,names[igroup]);

    if (logfile) fprintf(logfile,"%d atoms in group %s\n",all,names[igroup]);

    if (screen) fprintf(screen,"%.15g atoms in group %s\n",all,names[igroup]);

    if (logfile)

      fprintf(logfile,"%.15g atoms in group %s\n",all,names[igroup]);

  }

}