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 r303929 = x;
        double r303930 = 1.0;
        double r303931 = r303929 + r303930;
        double r303932 = sqrt(r303931);
        double r303933 = sqrt(r303929);
        double r303934 = r303932 - r303933;
        double r303935 = y;
        double r303936 = r303935 + r303930;
        double r303937 = sqrt(r303936);
        double r303938 = sqrt(r303935);
        double r303939 = r303937 - r303938;
        double r303940 = r303934 + r303939;
        double r303941 = z;
        double r303942 = r303941 + r303930;
        double r303943 = sqrt(r303942);
        double r303944 = sqrt(r303941);
        double r303945 = r303943 - r303944;
        double r303946 = r303940 + r303945;
        double r303947 = t;
        double r303948 = r303947 + r303930;
        double r303949 = sqrt(r303948);
        double r303950 = sqrt(r303947);
        double r303951 = r303949 - r303950;
        double r303952 = r303946 + r303951;
        return r303952;
}