image correction for fragment location

    for (int i = 0; i < 3; i++)

      center[i] = x[iatom][i];

  } else {

    int iref = -1; // choose first atom as reference

    int iatom;

    int nfragatoms = 0;

    for (int i = 0; i < 3; i++)

      center[i] = 0;

    for (int i = 0; i < onemol->natoms; i++) {

      if (onemol->fragmentmask[myID][i]) {

        if (iref == -1)

          iref = atom->map(glove[i][1]);

        for (int j = 0; j < 3; j++) {

          center[j] += x[atom->map(glove[i][1])][j];

          iatom = atom->map(glove[i][1]);

          iatom = domain->closest_image(iref,iatom);

          center[j] += x[iatom][j];

        }

        nfragatoms++;

      }