      static double mp_breakpoint(_cimg_math_parser& mp) {
        cimg_abort_init;
        cimg_abort_test;
        cimg::unused(mp);
        return cimg::type<double>::nan();
      }
      static double mp_breakpoint(_cimg_math_parser& mp) {
        cimg_abort_init;
        cimg_abort_test;
        cimg::unused(mp);
        return cimg::type<double>::nan();
      }