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 r502756 = x;
        double r502757 = 1.0;
        double r502758 = r502756 + r502757;
        double r502759 = sqrt(r502758);
        double r502760 = sqrt(r502756);
        double r502761 = r502759 - r502760;
        double r502762 = y;
        double r502763 = r502762 + r502757;
        double r502764 = sqrt(r502763);
        double r502765 = sqrt(r502762);
        double r502766 = r502764 - r502765;
        double r502767 = r502761 + r502766;
        double r502768 = z;
        double r502769 = r502768 + r502757;
        double r502770 = sqrt(r502769);
        double r502771 = sqrt(r502768);
        double r502772 = r502770 - r502771;
        double r502773 = r502767 + r502772;
        double r502774 = t;
        double r502775 = r502774 + r502757;
        double r502776 = sqrt(r502775);
        double r502777 = sqrt(r502774);
        double r502778 = r502776 - r502777;
        double r502779 = r502773 + r502778;
        return r502779;
}