assert(group.disttype == CCTK_DISTRIB_DEFAULT);
    assert(group.dim == dim);

    assert(group.disttype == CCTK_DISTRIB_CONSTANT);
    assert(group.dim == 0);

    scalargroupdata.valid.resize(group.numtimelevels);

      scalargroupdata.valid.at(tl).resize(scalargroupdata.numvars);