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 r8340 = 1.0;
        double r8341 = atan2(1.0, 0.0);
        double r8342 = 4.0;
        double r8343 = r8341 / r8342;
        double r8344 = r8340 / r8343;
        double r8345 = f;
        double r8346 = r8343 * r8345;
        double r8347 = exp(r8346);
        double r8348 = -r8346;
        double r8349 = exp(r8348);
        double r8350 = r8347 + r8349;
        double r8351 = r8347 - r8349;
        double r8352 = r8350 / r8351;
        double r8353 = log(r8352);
        double r8354 = r8344 * r8353;
        double r8355 = -r8354;
        return r8355;
}