\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\ell \cdot \pi - 1 \cdot \frac{\frac{1}{F} \cdot \tan \left(\left(\left(\left(\sqrt{\sqrt[3]{\pi}} \cdot \sqrt{\sqrt[3]{\pi}}\right) \cdot \left(\sqrt{\sqrt[3]{\pi}} \cdot \sqrt{\sqrt[3]{\pi}}\right)\right) \cdot \ell\right) \cdot \sqrt[3]{\pi}\right)}{F}double f(double F, double l) {
double r746744 = atan2(1.0, 0.0);
double r746745 = l;
double r746746 = r746744 * r746745;
double r746747 = 1.0;
double r746748 = F;
double r746749 = r746748 * r746748;
double r746750 = r746747 / r746749;
double r746751 = tan(r746746);
double r746752 = r746750 * r746751;
double r746753 = r746746 - r746752;
return r746753;
}
double f(double F, double l) {
double r746754 = l;
double r746755 = atan2(1.0, 0.0);
double r746756 = r746754 * r746755;
double r746757 = 1.0;
double r746758 = 1.0;
double r746759 = F;
double r746760 = r746758 / r746759;
double r746761 = cbrt(r746755);
double r746762 = sqrt(r746761);
double r746763 = r746762 * r746762;
double r746764 = r746763 * r746763;
double r746765 = r746764 * r746754;
double r746766 = r746765 * r746761;
double r746767 = tan(r746766);
double r746768 = r746760 * r746767;
double r746769 = r746768 / r746759;
double r746770 = r746757 * r746769;
double r746771 = r746756 - r746770;
return r746771;
}



Bits error versus F



Bits error versus l
Results
Initial program 16.5
rmApplied div-inv16.5
Applied associate-*l*16.5
Simplified12.3
rmApplied div-inv12.3
rmApplied add-cube-cbrt12.6
Applied associate-*r*12.6
rmApplied add-sqr-sqrt12.4
Applied add-sqr-sqrt12.3
Applied swap-sqr12.3
Final simplification12.3
herbie shell --seed 2019200 +o rules:numerics
(FPCore (F l)
:name "VandenBroeck and Keller, Equation (6)"
(- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))