\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\pi \cdot \ell - \frac{1}{F} \cdot \left(\frac{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 r13320 = atan2(1.0, 0.0);
double r13321 = l;
double r13322 = r13320 * r13321;
double r13323 = 1.0;
double r13324 = F;
double r13325 = r13324 * r13324;
double r13326 = r13323 / r13325;
double r13327 = tan(r13322);
double r13328 = r13326 * r13327;
double r13329 = r13322 - r13328;
return r13329;
}
double f(double F, double l) {
double r13330 = atan2(1.0, 0.0);
double r13331 = l;
double r13332 = r13330 * r13331;
double r13333 = 1.0;
double r13334 = F;
double r13335 = r13333 / r13334;
double r13336 = 1.0;
double r13337 = r13336 / r13334;
double r13338 = sqrt(r13330);
double r13339 = sqrt(r13338);
double r13340 = r13339 * r13339;
double r13341 = r13340 * r13331;
double r13342 = r13340 * r13341;
double r13343 = tan(r13342);
double r13344 = r13337 * r13343;
double r13345 = r13335 * r13344;
double r13346 = r13332 - r13345;
return r13346;
}



Bits error versus F



Bits error versus l
Results
Initial program 16.6
rmApplied *-un-lft-identity16.6
Applied times-frac16.7
Applied associate-*l*12.6
rmApplied add-sqr-sqrt12.7
Applied associate-*l*12.7
rmApplied add-sqr-sqrt12.7
Applied sqrt-prod12.6
rmApplied add-sqr-sqrt12.6
Applied sqrt-prod12.6
Final simplification12.6
herbie shell --seed 2020060 +o rules:numerics
(FPCore (F l)
:name "VandenBroeck and Keller, Equation (6)"
:precision binary64
(- (* PI l) (* (/ 1 (* F F)) (tan (* PI l)))))