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 r489644 = x;
        double r489645 = 1.0;
        double r489646 = r489644 + r489645;
        double r489647 = sqrt(r489646);
        double r489648 = sqrt(r489644);
        double r489649 = r489647 - r489648;
        double r489650 = y;
        double r489651 = r489650 + r489645;
        double r489652 = sqrt(r489651);
        double r489653 = sqrt(r489650);
        double r489654 = r489652 - r489653;
        double r489655 = r489649 + r489654;
        double r489656 = z;
        double r489657 = r489656 + r489645;
        double r489658 = sqrt(r489657);
        double r489659 = sqrt(r489656);
        double r489660 = r489658 - r489659;
        double r489661 = r489655 + r489660;
        double r489662 = t;
        double r489663 = r489662 + r489645;
        double r489664 = sqrt(r489663);
        double r489665 = sqrt(r489662);
        double r489666 = r489664 - r489665;
        double r489667 = r489661 + r489666;
        return r489667;
}