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 r8085 = 1.0;
        double r8086 = atan2(1.0, 0.0);
        double r8087 = 4.0;
        double r8088 = r8086 / r8087;
        double r8089 = r8085 / r8088;
        double r8090 = f;
        double r8091 = r8088 * r8090;
        double r8092 = exp(r8091);
        double r8093 = -r8091;
        double r8094 = exp(r8093);
        double r8095 = r8092 + r8094;
        double r8096 = r8092 - r8094;
        double r8097 = r8095 / r8096;
        double r8098 = log(r8097);
        double r8099 = r8089 * r8098;
        double r8100 = -r8099;
        return r8100;
}