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 r7970 = 1.0;
        double r7971 = atan2(1.0, 0.0);
        double r7972 = 4.0;
        double r7973 = r7971 / r7972;
        double r7974 = r7970 / r7973;
        double r7975 = f;
        double r7976 = r7973 * r7975;
        double r7977 = exp(r7976);
        double r7978 = -r7976;
        double r7979 = exp(r7978);
        double r7980 = r7977 + r7979;
        double r7981 = r7977 - r7979;
        double r7982 = r7980 / r7981;
        double r7983 = log(r7982);
        double r7984 = r7974 * r7983;
        double r7985 = -r7984;
        return r7985;
}