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 r290756 = x;
        double r290757 = 1.0;
        double r290758 = r290756 + r290757;
        double r290759 = sqrt(r290758);
        double r290760 = sqrt(r290756);
        double r290761 = r290759 - r290760;
        double r290762 = y;
        double r290763 = r290762 + r290757;
        double r290764 = sqrt(r290763);
        double r290765 = sqrt(r290762);
        double r290766 = r290764 - r290765;
        double r290767 = r290761 + r290766;
        double r290768 = z;
        double r290769 = r290768 + r290757;
        double r290770 = sqrt(r290769);
        double r290771 = sqrt(r290768);
        double r290772 = r290770 - r290771;
        double r290773 = r290767 + r290772;
        double r290774 = t;
        double r290775 = r290774 + r290757;
        double r290776 = sqrt(r290775);
        double r290777 = sqrt(r290774);
        double r290778 = r290776 - r290777;
        double r290779 = r290773 + r290778;
        return r290779;
}