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 r30636085 = x;
        double r30636086 = 1.0;
        double r30636087 = r30636085 + r30636086;
        double r30636088 = sqrt(r30636087);
        double r30636089 = sqrt(r30636085);
        double r30636090 = r30636088 - r30636089;
        double r30636091 = y;
        double r30636092 = r30636091 + r30636086;
        double r30636093 = sqrt(r30636092);
        double r30636094 = sqrt(r30636091);
        double r30636095 = r30636093 - r30636094;
        double r30636096 = r30636090 + r30636095;
        double r30636097 = z;
        double r30636098 = r30636097 + r30636086;
        double r30636099 = sqrt(r30636098);
        double r30636100 = sqrt(r30636097);
        double r30636101 = r30636099 - r30636100;
        double r30636102 = r30636096 + r30636101;
        double r30636103 = t;
        double r30636104 = r30636103 + r30636086;
        double r30636105 = sqrt(r30636104);
        double r30636106 = sqrt(r30636103);
        double r30636107 = r30636105 - r30636106;
        double r30636108 = r30636102 + r30636107;
        return r30636108;
}