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 r132 = 1.0;
        double r133 = atan2(1.0, 0.0);
        double r134 = 4.0;
        double r135 = r133 / r134;
        double r136 = r132 / r135;
        double r137 = f;
        double r138 = r135 * r137;
        double r139 = exp(r138);
        double r140 = -r138;
        double r141 = exp(r140);
        double r142 = r139 + r141;
        double r143 = r139 - r141;
        double r144 = r142 / r143;
        double r145 = log(r144);
        double r146 = r136 * r145;
        double r147 = -r146;
        return r147;
}