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 r447722 = x;
        double r447723 = 1.0;
        double r447724 = r447722 + r447723;
        double r447725 = sqrt(r447724);
        double r447726 = sqrt(r447722);
        double r447727 = r447725 - r447726;
        double r447728 = y;
        double r447729 = r447728 + r447723;
        double r447730 = sqrt(r447729);
        double r447731 = sqrt(r447728);
        double r447732 = r447730 - r447731;
        double r447733 = r447727 + r447732;
        double r447734 = z;
        double r447735 = r447734 + r447723;
        double r447736 = sqrt(r447735);
        double r447737 = sqrt(r447734);
        double r447738 = r447736 - r447737;
        double r447739 = r447733 + r447738;
        double r447740 = t;
        double r447741 = r447740 + r447723;
        double r447742 = sqrt(r447741);
        double r447743 = sqrt(r447740);
        double r447744 = r447742 - r447743;
        double r447745 = r447739 + r447744;
        return r447745;
}