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 r8029007 = x;
        double r8029008 = 1.0;
        double r8029009 = r8029007 + r8029008;
        double r8029010 = sqrt(r8029009);
        double r8029011 = sqrt(r8029007);
        double r8029012 = r8029010 - r8029011;
        double r8029013 = y;
        double r8029014 = r8029013 + r8029008;
        double r8029015 = sqrt(r8029014);
        double r8029016 = sqrt(r8029013);
        double r8029017 = r8029015 - r8029016;
        double r8029018 = r8029012 + r8029017;
        double r8029019 = z;
        double r8029020 = r8029019 + r8029008;
        double r8029021 = sqrt(r8029020);
        double r8029022 = sqrt(r8029019);
        double r8029023 = r8029021 - r8029022;
        double r8029024 = r8029018 + r8029023;
        double r8029025 = t;
        double r8029026 = r8029025 + r8029008;
        double r8029027 = sqrt(r8029026);
        double r8029028 = sqrt(r8029025);
        double r8029029 = r8029027 - r8029028;
        double r8029030 = r8029024 + r8029029;
        return r8029030;
}