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 r324904 = x;
        double r324905 = 1.0;
        double r324906 = r324904 + r324905;
        double r324907 = sqrt(r324906);
        double r324908 = sqrt(r324904);
        double r324909 = r324907 - r324908;
        double r324910 = y;
        double r324911 = r324910 + r324905;
        double r324912 = sqrt(r324911);
        double r324913 = sqrt(r324910);
        double r324914 = r324912 - r324913;
        double r324915 = r324909 + r324914;
        double r324916 = z;
        double r324917 = r324916 + r324905;
        double r324918 = sqrt(r324917);
        double r324919 = sqrt(r324916);
        double r324920 = r324918 - r324919;
        double r324921 = r324915 + r324920;
        double r324922 = t;
        double r324923 = r324922 + r324905;
        double r324924 = sqrt(r324923);
        double r324925 = sqrt(r324922);
        double r324926 = r324924 - r324925;
        double r324927 = r324921 + r324926;
        return r324927;
}