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 r397442 = x;
        double r397443 = 1.0;
        double r397444 = r397442 + r397443;
        double r397445 = sqrt(r397444);
        double r397446 = sqrt(r397442);
        double r397447 = r397445 - r397446;
        double r397448 = y;
        double r397449 = r397448 + r397443;
        double r397450 = sqrt(r397449);
        double r397451 = sqrt(r397448);
        double r397452 = r397450 - r397451;
        double r397453 = r397447 + r397452;
        double r397454 = z;
        double r397455 = r397454 + r397443;
        double r397456 = sqrt(r397455);
        double r397457 = sqrt(r397454);
        double r397458 = r397456 - r397457;
        double r397459 = r397453 + r397458;
        double r397460 = t;
        double r397461 = r397460 + r397443;
        double r397462 = sqrt(r397461);
        double r397463 = sqrt(r397460);
        double r397464 = r397462 - r397463;
        double r397465 = r397459 + r397464;
        return r397465;
}