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 r653722 = x;
        double r653723 = 1.0;
        double r653724 = r653722 + r653723;
        double r653725 = sqrt(r653724);
        double r653726 = sqrt(r653722);
        double r653727 = r653725 - r653726;
        double r653728 = y;
        double r653729 = r653728 + r653723;
        double r653730 = sqrt(r653729);
        double r653731 = sqrt(r653728);
        double r653732 = r653730 - r653731;
        double r653733 = r653727 + r653732;
        double r653734 = z;
        double r653735 = r653734 + r653723;
        double r653736 = sqrt(r653735);
        double r653737 = sqrt(r653734);
        double r653738 = r653736 - r653737;
        double r653739 = r653733 + r653738;
        double r653740 = t;
        double r653741 = r653740 + r653723;
        double r653742 = sqrt(r653741);
        double r653743 = sqrt(r653740);
        double r653744 = r653742 - r653743;
        double r653745 = r653739 + r653744;
        return r653745;
}