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 r164025935 = x;
        double r164025936 = 1.0;
        double r164025937 = r164025935 + r164025936;
        double r164025938 = sqrt(r164025937);
        double r164025939 = sqrt(r164025935);
        double r164025940 = r164025938 - r164025939;
        double r164025941 = y;
        double r164025942 = r164025941 + r164025936;
        double r164025943 = sqrt(r164025942);
        double r164025944 = sqrt(r164025941);
        double r164025945 = r164025943 - r164025944;
        double r164025946 = r164025940 + r164025945;
        double r164025947 = z;
        double r164025948 = r164025947 + r164025936;
        double r164025949 = sqrt(r164025948);
        double r164025950 = sqrt(r164025947);
        double r164025951 = r164025949 - r164025950;
        double r164025952 = r164025946 + r164025951;
        double r164025953 = t;
        double r164025954 = r164025953 + r164025936;
        double r164025955 = sqrt(r164025954);
        double r164025956 = sqrt(r164025953);
        double r164025957 = r164025955 - r164025956;
        double r164025958 = r164025952 + r164025957;
        return r164025958;
}