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 r8152 = 1.0;
        double r8153 = atan2(1.0, 0.0);
        double r8154 = 4.0;
        double r8155 = r8153 / r8154;
        double r8156 = r8152 / r8155;
        double r8157 = f;
        double r8158 = r8155 * r8157;
        double r8159 = exp(r8158);
        double r8160 = -r8158;
        double r8161 = exp(r8160);
        double r8162 = r8159 + r8161;
        double r8163 = r8159 - r8161;
        double r8164 = r8162 / r8163;
        double r8165 = log(r8164);
        double r8166 = r8156 * r8165;
        double r8167 = -r8166;
        return r8167;
}