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 r8090 = 1.0;
        double r8091 = atan2(1.0, 0.0);
        double r8092 = 4.0;
        double r8093 = r8091 / r8092;
        double r8094 = r8090 / r8093;
        double r8095 = f;
        double r8096 = r8093 * r8095;
        double r8097 = exp(r8096);
        double r8098 = -r8096;
        double r8099 = exp(r8098);
        double r8100 = r8097 + r8099;
        double r8101 = r8097 - r8099;
        double r8102 = r8100 / r8101;
        double r8103 = log(r8102);
        double r8104 = r8094 * r8103;
        double r8105 = -r8104;
        return r8105;
}