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 r8074 = 1.0;
        double r8075 = atan2(1.0, 0.0);
        double r8076 = 4.0;
        double r8077 = r8075 / r8076;
        double r8078 = r8074 / r8077;
        double r8079 = f;
        double r8080 = r8077 * r8079;
        double r8081 = exp(r8080);
        double r8082 = -r8080;
        double r8083 = exp(r8082);
        double r8084 = r8081 + r8083;
        double r8085 = r8081 - r8083;
        double r8086 = r8084 / r8085;
        double r8087 = log(r8086);
        double r8088 = r8078 * r8087;
        double r8089 = -r8088;
        return r8089;
}