\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 \left(\frac{\sqrt[3]{1}}{F} \cdot \tan \left(\sqrt{\sqrt{\pi}} \cdot \left(\sqrt{\sqrt{\pi}} \cdot \left(\left(\sqrt{\sqrt{\pi}} \cdot \sqrt{\sqrt{\pi}}\right) \cdot \ell\right)\right)\right)\right)double f(double F, double l) {
double r14675 = atan2(1.0, 0.0);
double r14676 = l;
double r14677 = r14675 * r14676;
double r14678 = 1.0;
double r14679 = F;
double r14680 = r14679 * r14679;
double r14681 = r14678 / r14680;
double r14682 = tan(r14677);
double r14683 = r14681 * r14682;
double r14684 = r14677 - r14683;
return r14684;
}
double f(double F, double l) {
double r14685 = atan2(1.0, 0.0);
double r14686 = l;
double r14687 = r14685 * r14686;
double r14688 = 1.0;
double r14689 = cbrt(r14688);
double r14690 = r14689 * r14689;
double r14691 = F;
double r14692 = r14690 / r14691;
double r14693 = r14689 / r14691;
double r14694 = sqrt(r14685);
double r14695 = sqrt(r14694);
double r14696 = r14695 * r14695;
double r14697 = r14696 * r14686;
double r14698 = r14695 * r14697;
double r14699 = r14695 * r14698;
double r14700 = tan(r14699);
double r14701 = r14693 * r14700;
double r14702 = r14692 * r14701;
double r14703 = r14687 - r14702;
return r14703;
}



Bits error versus F



Bits error versus l
Results
Initial program 16.9
rmApplied add-cube-cbrt16.9
Applied times-frac16.9
Applied associate-*l*12.8
rmApplied add-sqr-sqrt12.9
Applied associate-*l*12.9
rmApplied add-sqr-sqrt12.9
Applied sqrt-prod12.8
Applied associate-*l*12.8
rmApplied add-sqr-sqrt12.8
Applied sqrt-prod12.8
Final simplification12.8
herbie shell --seed 2020034 +o rules:numerics
(FPCore (F l)
:name "VandenBroeck and Keller, Equation (6)"
:precision binary64
(- (* PI l) (* (/ 1 (* F F)) (tan (* PI l)))))