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 r477943 = x;
        double r477944 = 1.0;
        double r477945 = r477943 + r477944;
        double r477946 = sqrt(r477945);
        double r477947 = sqrt(r477943);
        double r477948 = r477946 - r477947;
        double r477949 = y;
        double r477950 = r477949 + r477944;
        double r477951 = sqrt(r477950);
        double r477952 = sqrt(r477949);
        double r477953 = r477951 - r477952;
        double r477954 = r477948 + r477953;
        double r477955 = z;
        double r477956 = r477955 + r477944;
        double r477957 = sqrt(r477956);
        double r477958 = sqrt(r477955);
        double r477959 = r477957 - r477958;
        double r477960 = r477954 + r477959;
        double r477961 = t;
        double r477962 = r477961 + r477944;
        double r477963 = sqrt(r477962);
        double r477964 = sqrt(r477961);
        double r477965 = r477963 - r477964;
        double r477966 = r477960 + r477965;
        return r477966;
}