Cannot sample enough valid points. (more)

\[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\]
-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)
double f(double f) {
        double r8278 = 1.0;
        double r8279 = atan2(1.0, 0.0);
        double r8280 = 4.0;
        double r8281 = r8279 / r8280;
        double r8282 = r8278 / r8281;
        double r8283 = f;
        double r8284 = r8281 * r8283;
        double r8285 = exp(r8284);
        double r8286 = -r8284;
        double r8287 = exp(r8286);
        double r8288 = r8285 + r8287;
        double r8289 = r8285 - r8287;
        double r8290 = r8288 / r8289;
        double r8291 = log(r8290);
        double r8292 = r8282 * r8291;
        double r8293 = -r8292;
        return r8293;
}