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 r559763 = x;
        double r559764 = 1.0;
        double r559765 = r559763 + r559764;
        double r559766 = sqrt(r559765);
        double r559767 = sqrt(r559763);
        double r559768 = r559766 - r559767;
        double r559769 = y;
        double r559770 = r559769 + r559764;
        double r559771 = sqrt(r559770);
        double r559772 = sqrt(r559769);
        double r559773 = r559771 - r559772;
        double r559774 = r559768 + r559773;
        double r559775 = z;
        double r559776 = r559775 + r559764;
        double r559777 = sqrt(r559776);
        double r559778 = sqrt(r559775);
        double r559779 = r559777 - r559778;
        double r559780 = r559774 + r559779;
        double r559781 = t;
        double r559782 = r559781 + r559764;
        double r559783 = sqrt(r559782);
        double r559784 = sqrt(r559781);
        double r559785 = r559783 - r559784;
        double r559786 = r559780 + r559785;
        return r559786;
}