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 r359540 = x;
        double r359541 = 1.0;
        double r359542 = r359540 + r359541;
        double r359543 = sqrt(r359542);
        double r359544 = sqrt(r359540);
        double r359545 = r359543 - r359544;
        double r359546 = y;
        double r359547 = r359546 + r359541;
        double r359548 = sqrt(r359547);
        double r359549 = sqrt(r359546);
        double r359550 = r359548 - r359549;
        double r359551 = r359545 + r359550;
        double r359552 = z;
        double r359553 = r359552 + r359541;
        double r359554 = sqrt(r359553);
        double r359555 = sqrt(r359552);
        double r359556 = r359554 - r359555;
        double r359557 = r359551 + r359556;
        double r359558 = t;
        double r359559 = r359558 + r359541;
        double r359560 = sqrt(r359559);
        double r359561 = sqrt(r359558);
        double r359562 = r359560 - r359561;
        double r359563 = r359557 + r359562;
        return r359563;
}