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 r710006 = x;
        double r710007 = 1.0;
        double r710008 = r710006 + r710007;
        double r710009 = sqrt(r710008);
        double r710010 = sqrt(r710006);
        double r710011 = r710009 - r710010;
        double r710012 = y;
        double r710013 = r710012 + r710007;
        double r710014 = sqrt(r710013);
        double r710015 = sqrt(r710012);
        double r710016 = r710014 - r710015;
        double r710017 = r710011 + r710016;
        double r710018 = z;
        double r710019 = r710018 + r710007;
        double r710020 = sqrt(r710019);
        double r710021 = sqrt(r710018);
        double r710022 = r710020 - r710021;
        double r710023 = r710017 + r710022;
        double r710024 = t;
        double r710025 = r710024 + r710007;
        double r710026 = sqrt(r710025);
        double r710027 = sqrt(r710024);
        double r710028 = r710026 - r710027;
        double r710029 = r710023 + r710028;
        return r710029;
}