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 r366598 = x;
        double r366599 = 1.0;
        double r366600 = r366598 + r366599;
        double r366601 = sqrt(r366600);
        double r366602 = sqrt(r366598);
        double r366603 = r366601 - r366602;
        double r366604 = y;
        double r366605 = r366604 + r366599;
        double r366606 = sqrt(r366605);
        double r366607 = sqrt(r366604);
        double r366608 = r366606 - r366607;
        double r366609 = r366603 + r366608;
        double r366610 = z;
        double r366611 = r366610 + r366599;
        double r366612 = sqrt(r366611);
        double r366613 = sqrt(r366610);
        double r366614 = r366612 - r366613;
        double r366615 = r366609 + r366614;
        double r366616 = t;
        double r366617 = r366616 + r366599;
        double r366618 = sqrt(r366617);
        double r366619 = sqrt(r366616);
        double r366620 = r366618 - r366619;
        double r366621 = r366615 + r366620;
        return r366621;
}