\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\pi \cdot \ell - \frac{\sqrt{1}}{F} \cdot \left(\frac{\sqrt{\sqrt{1}}}{\sqrt[3]{F} \cdot \sqrt[3]{F}} \cdot \left(\frac{\sqrt{\sqrt{1}}}{\sqrt[3]{F}} \cdot \tan \left(\pi \cdot \ell\right)\right)\right)double code(double F, double l) {
return ((((double) M_PI) * l) - ((1.0 / (F * F)) * tan((((double) M_PI) * l))));
}
double code(double F, double l) {
return ((((double) M_PI) * l) - ((sqrt(1.0) / F) * ((sqrt(sqrt(1.0)) / (cbrt(F) * cbrt(F))) * ((sqrt(sqrt(1.0)) / cbrt(F)) * tan((((double) M_PI) * l))))));
}



Bits error versus F



Bits error versus l
Results
Initial program 16.5
rmApplied add-sqr-sqrt16.5
Applied times-frac16.5
Applied associate-*l*12.3
rmApplied add-cube-cbrt12.5
Applied add-sqr-sqrt12.5
Applied sqrt-prod12.5
Applied times-frac12.5
Applied associate-*l*12.5
Final simplification12.5
herbie shell --seed 2020057 +o rules:numerics
(FPCore (F l)
:name "VandenBroeck and Keller, Equation (6)"
:precision binary64
(- (* PI l) (* (/ 1 (* F F)) (tan (* PI l)))))