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 r7977 = 1.0;
        double r7978 = atan2(1.0, 0.0);
        double r7979 = 4.0;
        double r7980 = r7978 / r7979;
        double r7981 = r7977 / r7980;
        double r7982 = f;
        double r7983 = r7980 * r7982;
        double r7984 = exp(r7983);
        double r7985 = -r7983;
        double r7986 = exp(r7985);
        double r7987 = r7984 + r7986;
        double r7988 = r7984 - r7986;
        double r7989 = r7987 / r7988;
        double r7990 = log(r7989);
        double r7991 = r7981 * r7990;
        double r7992 = -r7991;
        return r7992;
}