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 r8089 = 1.0;
        double r8090 = atan2(1.0, 0.0);
        double r8091 = 4.0;
        double r8092 = r8090 / r8091;
        double r8093 = r8089 / r8092;
        double r8094 = f;
        double r8095 = r8092 * r8094;
        double r8096 = exp(r8095);
        double r8097 = -r8095;
        double r8098 = exp(r8097);
        double r8099 = r8096 + r8098;
        double r8100 = r8096 - r8098;
        double r8101 = r8099 / r8100;
        double r8102 = log(r8101);
        double r8103 = r8093 * r8102;
        double r8104 = -r8103;
        return r8104;
}