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 r538359 = x;
        double r538360 = 1.0;
        double r538361 = r538359 + r538360;
        double r538362 = sqrt(r538361);
        double r538363 = sqrt(r538359);
        double r538364 = r538362 - r538363;
        double r538365 = y;
        double r538366 = r538365 + r538360;
        double r538367 = sqrt(r538366);
        double r538368 = sqrt(r538365);
        double r538369 = r538367 - r538368;
        double r538370 = r538364 + r538369;
        double r538371 = z;
        double r538372 = r538371 + r538360;
        double r538373 = sqrt(r538372);
        double r538374 = sqrt(r538371);
        double r538375 = r538373 - r538374;
        double r538376 = r538370 + r538375;
        double r538377 = t;
        double r538378 = r538377 + r538360;
        double r538379 = sqrt(r538378);
        double r538380 = sqrt(r538377);
        double r538381 = r538379 - r538380;
        double r538382 = r538376 + r538381;
        return r538382;
}