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 r19061204 = x;
        double r19061205 = 1.0;
        double r19061206 = r19061204 + r19061205;
        double r19061207 = sqrt(r19061206);
        double r19061208 = sqrt(r19061204);
        double r19061209 = r19061207 - r19061208;
        double r19061210 = y;
        double r19061211 = r19061210 + r19061205;
        double r19061212 = sqrt(r19061211);
        double r19061213 = sqrt(r19061210);
        double r19061214 = r19061212 - r19061213;
        double r19061215 = r19061209 + r19061214;
        double r19061216 = z;
        double r19061217 = r19061216 + r19061205;
        double r19061218 = sqrt(r19061217);
        double r19061219 = sqrt(r19061216);
        double r19061220 = r19061218 - r19061219;
        double r19061221 = r19061215 + r19061220;
        double r19061222 = t;
        double r19061223 = r19061222 + r19061205;
        double r19061224 = sqrt(r19061223);
        double r19061225 = sqrt(r19061222);
        double r19061226 = r19061224 - r19061225;
        double r19061227 = r19061221 + r19061226;
        return r19061227;
}