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 r291029 = x;
        double r291030 = 1.0;
        double r291031 = r291029 + r291030;
        double r291032 = sqrt(r291031);
        double r291033 = sqrt(r291029);
        double r291034 = r291032 - r291033;
        double r291035 = y;
        double r291036 = r291035 + r291030;
        double r291037 = sqrt(r291036);
        double r291038 = sqrt(r291035);
        double r291039 = r291037 - r291038;
        double r291040 = r291034 + r291039;
        double r291041 = z;
        double r291042 = r291041 + r291030;
        double r291043 = sqrt(r291042);
        double r291044 = sqrt(r291041);
        double r291045 = r291043 - r291044;
        double r291046 = r291040 + r291045;
        double r291047 = t;
        double r291048 = r291047 + r291030;
        double r291049 = sqrt(r291048);
        double r291050 = sqrt(r291047);
        double r291051 = r291049 - r291050;
        double r291052 = r291046 + r291051;
        return r291052;
}