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 r8338 = 1.0;
        double r8339 = atan2(1.0, 0.0);
        double r8340 = 4.0;
        double r8341 = r8339 / r8340;
        double r8342 = r8338 / r8341;
        double r8343 = f;
        double r8344 = r8341 * r8343;
        double r8345 = exp(r8344);
        double r8346 = -r8344;
        double r8347 = exp(r8346);
        double r8348 = r8345 + r8347;
        double r8349 = r8345 - r8347;
        double r8350 = r8348 / r8349;
        double r8351 = log(r8350);
        double r8352 = r8342 * r8351;
        double r8353 = -r8352;
        return r8353;
}