\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\pi \cdot \ell - \frac{\frac{\sqrt[3]{\tan \left(\left(\sqrt[3]{\ell} \cdot \sqrt[3]{\ell}\right) \cdot \left(\sqrt[3]{\ell} \cdot \pi\right)\right)} \cdot \left(\sqrt[3]{\tan \left(\left(\sqrt[3]{\ell} \cdot \sqrt[3]{\ell}\right) \cdot \left(\sqrt[3]{\ell} \cdot \pi\right)\right)} \cdot \sqrt[3]{\tan \left(\left(\sqrt[3]{\ell} \cdot \sqrt[3]{\ell}\right) \cdot \left(\sqrt[3]{\ell} \cdot \pi\right)\right)}\right)}{F}}{F} \cdot 1double f(double F, double l) {
double r789332 = atan2(1.0, 0.0);
double r789333 = l;
double r789334 = r789332 * r789333;
double r789335 = 1.0;
double r789336 = F;
double r789337 = r789336 * r789336;
double r789338 = r789335 / r789337;
double r789339 = tan(r789334);
double r789340 = r789338 * r789339;
double r789341 = r789334 - r789340;
return r789341;
}
double f(double F, double l) {
double r789342 = atan2(1.0, 0.0);
double r789343 = l;
double r789344 = r789342 * r789343;
double r789345 = cbrt(r789343);
double r789346 = r789345 * r789345;
double r789347 = r789345 * r789342;
double r789348 = r789346 * r789347;
double r789349 = tan(r789348);
double r789350 = cbrt(r789349);
double r789351 = r789350 * r789350;
double r789352 = r789350 * r789351;
double r789353 = F;
double r789354 = r789352 / r789353;
double r789355 = r789354 / r789353;
double r789356 = 1.0;
double r789357 = r789355 * r789356;
double r789358 = r789344 - r789357;
return r789358;
}



Bits error versus F



Bits error versus l
Results
Initial program 16.6
rmApplied div-inv16.6
Applied associate-*l*16.6
Simplified12.4
rmApplied add-cube-cbrt12.6
Applied associate-*l*12.6
rmApplied add-cube-cbrt12.7
Final simplification12.7
herbie shell --seed 2019172 +o rules:numerics
(FPCore (F l)
:name "VandenBroeck and Keller, Equation (6)"
(- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))