operator size_t () const { return m->index_to_point(index);}
/// Write into HDF5
friend void h5_write (tqa::h5::group_or_file fg, std::string subgroup_name, discrete_mesh const & m) {
tqa::h5::group_or_file gr = fg.create_group(subgroup_name);
h5_write(gr,"domain",m.domain());
}
/// Write into HDF5
friend void h5_write(h5::group fg, std::string subgroup_name, discrete_mesh const &m) {
h5::group gr = fg.create_group(subgroup_name);
h5_write(gr, "domain", m.domain());
}