      static double mp_list_norm(_cimg_math_parser& mp) {
        const unsigned int ind = (unsigned int)cimg::mod((int)_mp_arg(2),mp.imglist.width());
        if (!mp.list_norm) mp.list_norm.assign(mp.imglist._width);
        if (!mp.list_norm[ind]) CImg<doubleT>::vector(mp.imglist[ind].magnitude()).move_to(mp.list_norm[ind]);
        return *mp.list_norm[ind];
      }
      static double mp_list_norm(_cimg_math_parser& mp) {
        const unsigned int ind = (unsigned int)cimg::mod((int)_mp_arg(2),mp.imglist.width());
        if (!mp.list_norm) mp.list_norm.assign(mp.imglist._width);
        if (!mp.list_norm[ind]) CImg<doubleT>::vector(mp.imglist[ind].magnitude()).move_to(mp.list_norm[ind]);
        return *mp.list_norm[ind];
      }