Cannot sample enough valid points. (more)

\[\left(\left(\left(\sqrt{x + 1} - \sqrt{x}\right) + \left(\sqrt{y + 1} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1} - \sqrt{t}\right)\]
\left(\left(\left(\sqrt{x + 1} - \sqrt{x}\right) + \left(\sqrt{y + 1} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1} - \sqrt{t}\right)
double f(double x, double y, double z, double t) {
        double r492818 = x;
        double r492819 = 1.0;
        double r492820 = r492818 + r492819;
        double r492821 = sqrt(r492820);
        double r492822 = sqrt(r492818);
        double r492823 = r492821 - r492822;
        double r492824 = y;
        double r492825 = r492824 + r492819;
        double r492826 = sqrt(r492825);
        double r492827 = sqrt(r492824);
        double r492828 = r492826 - r492827;
        double r492829 = r492823 + r492828;
        double r492830 = z;
        double r492831 = r492830 + r492819;
        double r492832 = sqrt(r492831);
        double r492833 = sqrt(r492830);
        double r492834 = r492832 - r492833;
        double r492835 = r492829 + r492834;
        double r492836 = t;
        double r492837 = r492836 + r492819;
        double r492838 = sqrt(r492837);
        double r492839 = sqrt(r492836);
        double r492840 = r492838 - r492839;
        double r492841 = r492835 + r492840;
        return r492841;
}