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 r30012991 = x;
        double r30012992 = 1.0;
        double r30012993 = r30012991 + r30012992;
        double r30012994 = sqrt(r30012993);
        double r30012995 = sqrt(r30012991);
        double r30012996 = r30012994 - r30012995;
        double r30012997 = y;
        double r30012998 = r30012997 + r30012992;
        double r30012999 = sqrt(r30012998);
        double r30013000 = sqrt(r30012997);
        double r30013001 = r30012999 - r30013000;
        double r30013002 = r30012996 + r30013001;
        double r30013003 = z;
        double r30013004 = r30013003 + r30012992;
        double r30013005 = sqrt(r30013004);
        double r30013006 = sqrt(r30013003);
        double r30013007 = r30013005 - r30013006;
        double r30013008 = r30013002 + r30013007;
        double r30013009 = t;
        double r30013010 = r30013009 + r30012992;
        double r30013011 = sqrt(r30013010);
        double r30013012 = sqrt(r30013009);
        double r30013013 = r30013011 - r30013012;
        double r30013014 = r30013008 + r30013013;
        return r30013014;
}