\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{1}}{F} \cdot \tan \left(\left(\sqrt{\sqrt{\pi}} \cdot \sqrt{\sqrt{\pi}}\right) \cdot \left(\left(\sqrt{\sqrt{\pi}} \cdot \sqrt{\sqrt{\pi}}\right) \cdot \ell\right)\right)\right)double f(double F, double l) {
double r13868 = atan2(1.0, 0.0);
double r13869 = l;
double r13870 = r13868 * r13869;
double r13871 = 1.0;
double r13872 = F;
double r13873 = r13872 * r13872;
double r13874 = r13871 / r13873;
double r13875 = tan(r13870);
double r13876 = r13874 * r13875;
double r13877 = r13870 - r13876;
return r13877;
}
double f(double F, double l) {
double r13878 = atan2(1.0, 0.0);
double r13879 = l;
double r13880 = r13878 * r13879;
double r13881 = 1.0;
double r13882 = sqrt(r13881);
double r13883 = F;
double r13884 = r13882 / r13883;
double r13885 = sqrt(r13878);
double r13886 = sqrt(r13885);
double r13887 = r13886 * r13886;
double r13888 = r13887 * r13879;
double r13889 = r13887 * r13888;
double r13890 = tan(r13889);
double r13891 = r13884 * r13890;
double r13892 = r13884 * r13891;
double r13893 = r13880 - r13892;
return r13893;
}



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*12.1
rmApplied add-sqr-sqrt12.2
Applied associate-*l*12.1
rmApplied add-sqr-sqrt12.1
Applied sqrt-prod12.1
rmApplied add-sqr-sqrt12.1
Applied sqrt-prod12.1
Final simplification12.1
herbie shell --seed 2020047 +o rules:numerics
(FPCore (F l)
:name "VandenBroeck and Keller, Equation (6)"
:precision binary64
(- (* PI l) (* (/ 1 (* F F)) (tan (* PI l)))))