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 r526366 = x;
        double r526367 = 1.0;
        double r526368 = r526366 + r526367;
        double r526369 = sqrt(r526368);
        double r526370 = sqrt(r526366);
        double r526371 = r526369 - r526370;
        double r526372 = y;
        double r526373 = r526372 + r526367;
        double r526374 = sqrt(r526373);
        double r526375 = sqrt(r526372);
        double r526376 = r526374 - r526375;
        double r526377 = r526371 + r526376;
        double r526378 = z;
        double r526379 = r526378 + r526367;
        double r526380 = sqrt(r526379);
        double r526381 = sqrt(r526378);
        double r526382 = r526380 - r526381;
        double r526383 = r526377 + r526382;
        double r526384 = t;
        double r526385 = r526384 + r526367;
        double r526386 = sqrt(r526385);
        double r526387 = sqrt(r526384);
        double r526388 = r526386 - r526387;
        double r526389 = r526383 + r526388;
        return r526389;
}