template <typename T> struct reduction {
  T fmax1(T x, T y) {
    if (CCTK_isnan(x))
      return x;
    if (CCTK_isnan(y))
      return y;
    return fmax(x, y);
  }
  T fmin1(T x, T y) {
    if (CCTK_isnan(x))
      return x;
    if (CCTK_isnan(y))
      return y;
    return fmin(x, y);
  }

template <typename T> T fmax1(T x, T y) {
  if (CCTK_isnan(x))
    return x;
  if (CCTK_isnan(y))
    return y;
  return fmax(x, y);
}
template <typename T> T fmin1(T x, T y) {
  if (CCTK_isnan(x))
    return x;
  if (CCTK_isnan(y))
    return y;
  return fmin(x, y);
}

template <typename T> struct reduction {
  // TODO: contains_inf, contains_nan?
  // TODO: minloc, maxloc

      double pts0 = ghext->leveldata.at(0).mfab0->boxArray().d_numPts();
      for (const auto &leveldata : ghext->leveldata) {
        int sz = leveldata.mfab0->size();
        double pts = leveldata.mfab0->boxArray().d_numPts();
        CCTK_VINFO("  level %d: %d boxes, %.0f cells (%.4g%%)", leveldata.level,
                   sz, pts,
                   100 * pts / (pow(2.0, dim * leveldata.level) * pts0));
      }

      double pts0 = ghext->leveldata.at(0).mfab0->boxArray().d_numPts();
      for (const auto &leveldata : ghext->leveldata) {
        int sz = leveldata.mfab0->size();
        double pts = leveldata.mfab0->boxArray().d_numPts();
        CCTK_VINFO("  level %d: %d boxes, %.0f cells (%.4g%%)", leveldata.level,
                   sz, pts,
                   100 * pts / (pow(2.0, dim * leveldata.level) * pts0));
      }