Cannot sample enough valid points. (more)

\[\left(\left(\left(\sqrt{x + 1.0} - \sqrt{x}\right) + \left(\sqrt{y + 1.0} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1.0} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1.0} - \sqrt{t}\right)\]
\left(\left(\left(\sqrt{x + 1.0} - \sqrt{x}\right) + \left(\sqrt{y + 1.0} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1.0} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1.0} - \sqrt{t}\right)
double f(double x, double y, double z, double t) {
        double r23701838 = x;
        double r23701839 = 1.0;
        double r23701840 = r23701838 + r23701839;
        double r23701841 = sqrt(r23701840);
        double r23701842 = sqrt(r23701838);
        double r23701843 = r23701841 - r23701842;
        double r23701844 = y;
        double r23701845 = r23701844 + r23701839;
        double r23701846 = sqrt(r23701845);
        double r23701847 = sqrt(r23701844);
        double r23701848 = r23701846 - r23701847;
        double r23701849 = r23701843 + r23701848;
        double r23701850 = z;
        double r23701851 = r23701850 + r23701839;
        double r23701852 = sqrt(r23701851);
        double r23701853 = sqrt(r23701850);
        double r23701854 = r23701852 - r23701853;
        double r23701855 = r23701849 + r23701854;
        double r23701856 = t;
        double r23701857 = r23701856 + r23701839;
        double r23701858 = sqrt(r23701857);
        double r23701859 = sqrt(r23701856);
        double r23701860 = r23701858 - r23701859;
        double r23701861 = r23701855 + r23701860;
        return r23701861;
}