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 r438479 = x;
        double r438480 = 1.0;
        double r438481 = r438479 + r438480;
        double r438482 = sqrt(r438481);
        double r438483 = sqrt(r438479);
        double r438484 = r438482 - r438483;
        double r438485 = y;
        double r438486 = r438485 + r438480;
        double r438487 = sqrt(r438486);
        double r438488 = sqrt(r438485);
        double r438489 = r438487 - r438488;
        double r438490 = r438484 + r438489;
        double r438491 = z;
        double r438492 = r438491 + r438480;
        double r438493 = sqrt(r438492);
        double r438494 = sqrt(r438491);
        double r438495 = r438493 - r438494;
        double r438496 = r438490 + r438495;
        double r438497 = t;
        double r438498 = r438497 + r438480;
        double r438499 = sqrt(r438498);
        double r438500 = sqrt(r438497);
        double r438501 = r438499 - r438500;
        double r438502 = r438496 + r438501;
        return r438502;
}