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 r306984 = x;
        double r306985 = 1.0;
        double r306986 = r306984 + r306985;
        double r306987 = sqrt(r306986);
        double r306988 = sqrt(r306984);
        double r306989 = r306987 - r306988;
        double r306990 = y;
        double r306991 = r306990 + r306985;
        double r306992 = sqrt(r306991);
        double r306993 = sqrt(r306990);
        double r306994 = r306992 - r306993;
        double r306995 = r306989 + r306994;
        double r306996 = z;
        double r306997 = r306996 + r306985;
        double r306998 = sqrt(r306997);
        double r306999 = sqrt(r306996);
        double r307000 = r306998 - r306999;
        double r307001 = r306995 + r307000;
        double r307002 = t;
        double r307003 = r307002 + r306985;
        double r307004 = sqrt(r307003);
        double r307005 = sqrt(r307002);
        double r307006 = r307004 - r307005;
        double r307007 = r307001 + r307006;
        return r307007;
}