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 r8281 = 1.0;
        double r8282 = atan2(1.0, 0.0);
        double r8283 = 4.0;
        double r8284 = r8282 / r8283;
        double r8285 = r8281 / r8284;
        double r8286 = f;
        double r8287 = r8284 * r8286;
        double r8288 = exp(r8287);
        double r8289 = -r8287;
        double r8290 = exp(r8289);
        double r8291 = r8288 + r8290;
        double r8292 = r8288 - r8290;
        double r8293 = r8291 / r8292;
        double r8294 = log(r8293);
        double r8295 = r8285 * r8294;
        double r8296 = -r8295;
        return r8296;
}