\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\pi \cdot \ell - \frac{\sqrt[3]{1} \cdot \sqrt[3]{1}}{F} \cdot \frac{\frac{\sin \left(\pi \cdot \ell\right) \cdot \sqrt[3]{1}}{F}}{\cos \left(\sqrt{\pi} \cdot \left(\sqrt{\pi} \cdot \ell\right)\right)}double f(double F, double l) {
double r18809 = atan2(1.0, 0.0);
double r18810 = l;
double r18811 = r18809 * r18810;
double r18812 = 1.0;
double r18813 = F;
double r18814 = r18813 * r18813;
double r18815 = r18812 / r18814;
double r18816 = tan(r18811);
double r18817 = r18815 * r18816;
double r18818 = r18811 - r18817;
return r18818;
}
double f(double F, double l) {
double r18819 = atan2(1.0, 0.0);
double r18820 = l;
double r18821 = r18819 * r18820;
double r18822 = 1.0;
double r18823 = cbrt(r18822);
double r18824 = r18823 * r18823;
double r18825 = F;
double r18826 = r18824 / r18825;
double r18827 = sin(r18821);
double r18828 = r18827 * r18823;
double r18829 = r18828 / r18825;
double r18830 = sqrt(r18819);
double r18831 = r18830 * r18820;
double r18832 = r18830 * r18831;
double r18833 = cos(r18832);
double r18834 = r18829 / r18833;
double r18835 = r18826 * r18834;
double r18836 = r18821 - r18835;
return r18836;
}



Bits error versus F



Bits error versus l
Results
Initial program 16.7
rmApplied add-cube-cbrt16.7
Applied times-frac16.7
Applied associate-*l*12.4
rmApplied add-sqr-sqrt12.5
Applied associate-*l*12.5
rmApplied tan-quot12.5
Applied associate-*r/12.5
Simplified12.4
Final simplification12.4
herbie shell --seed 2020062 +o rules:numerics
(FPCore (F l)
:name "VandenBroeck and Keller, Equation (6)"
:precision binary64
(- (* PI l) (* (/ 1 (* F F)) (tan (* PI l)))))