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 r531238 = x;
        double r531239 = 1.0;
        double r531240 = r531238 + r531239;
        double r531241 = sqrt(r531240);
        double r531242 = sqrt(r531238);
        double r531243 = r531241 - r531242;
        double r531244 = y;
        double r531245 = r531244 + r531239;
        double r531246 = sqrt(r531245);
        double r531247 = sqrt(r531244);
        double r531248 = r531246 - r531247;
        double r531249 = r531243 + r531248;
        double r531250 = z;
        double r531251 = r531250 + r531239;
        double r531252 = sqrt(r531251);
        double r531253 = sqrt(r531250);
        double r531254 = r531252 - r531253;
        double r531255 = r531249 + r531254;
        double r531256 = t;
        double r531257 = r531256 + r531239;
        double r531258 = sqrt(r531257);
        double r531259 = sqrt(r531256);
        double r531260 = r531258 - r531259;
        double r531261 = r531255 + r531260;
        return r531261;
}