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 r8114 = 1.0;
        double r8115 = atan2(1.0, 0.0);
        double r8116 = 4.0;
        double r8117 = r8115 / r8116;
        double r8118 = r8114 / r8117;
        double r8119 = f;
        double r8120 = r8117 * r8119;
        double r8121 = exp(r8120);
        double r8122 = -r8120;
        double r8123 = exp(r8122);
        double r8124 = r8121 + r8123;
        double r8125 = r8121 - r8123;
        double r8126 = r8124 / r8125;
        double r8127 = log(r8126);
        double r8128 = r8118 * r8127;
        double r8129 = -r8128;
        return r8129;
}