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 r327267 = x;
        double r327268 = 1.0;
        double r327269 = r327267 + r327268;
        double r327270 = sqrt(r327269);
        double r327271 = sqrt(r327267);
        double r327272 = r327270 - r327271;
        double r327273 = y;
        double r327274 = r327273 + r327268;
        double r327275 = sqrt(r327274);
        double r327276 = sqrt(r327273);
        double r327277 = r327275 - r327276;
        double r327278 = r327272 + r327277;
        double r327279 = z;
        double r327280 = r327279 + r327268;
        double r327281 = sqrt(r327280);
        double r327282 = sqrt(r327279);
        double r327283 = r327281 - r327282;
        double r327284 = r327278 + r327283;
        double r327285 = t;
        double r327286 = r327285 + r327268;
        double r327287 = sqrt(r327286);
        double r327288 = sqrt(r327285);
        double r327289 = r327287 - r327288;
        double r327290 = r327284 + r327289;
        return r327290;
}