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 r8087 = 1.0;
        double r8088 = atan2(1.0, 0.0);
        double r8089 = 4.0;
        double r8090 = r8088 / r8089;
        double r8091 = r8087 / r8090;
        double r8092 = f;
        double r8093 = r8090 * r8092;
        double r8094 = exp(r8093);
        double r8095 = -r8093;
        double r8096 = exp(r8095);
        double r8097 = r8094 + r8096;
        double r8098 = r8094 - r8096;
        double r8099 = r8097 / r8098;
        double r8100 = log(r8099);
        double r8101 = r8091 * r8100;
        double r8102 = -r8101;
        return r8102;
}