\lambda_1 + \tan^{-1}_* \frac{\left(\sin theta \cdot \sin delta\right) \cdot \cos \phi_1}{\cos delta - \sin \phi_1 \cdot \sin \left(\sin^{-1} \left(\sin \phi_1 \cdot \cos delta + \left(\cos \phi_1 \cdot \sin delta\right) \cdot \cos theta\right)\right)}\tan^{-1}_* \frac{\left(\cos \phi_1 \cdot \sin theta\right) \cdot \sin delta}{\left(\cos delta \cdot \cos \phi_1 - \sin \phi_1 \cdot \left(\sin delta \cdot \cos theta\right)\right) \cdot \cos \phi_1} + \lambda_1double f(double lambda1, double phi1, double __attribute__((unused)) phi2, double delta, double theta) {
double r3882442 = lambda1;
double r3882443 = theta;
double r3882444 = sin(r3882443);
double r3882445 = delta;
double r3882446 = sin(r3882445);
double r3882447 = r3882444 * r3882446;
double r3882448 = phi1;
double r3882449 = cos(r3882448);
double r3882450 = r3882447 * r3882449;
double r3882451 = cos(r3882445);
double r3882452 = sin(r3882448);
double r3882453 = r3882452 * r3882451;
double r3882454 = r3882449 * r3882446;
double r3882455 = cos(r3882443);
double r3882456 = r3882454 * r3882455;
double r3882457 = r3882453 + r3882456;
double r3882458 = asin(r3882457);
double r3882459 = sin(r3882458);
double r3882460 = r3882452 * r3882459;
double r3882461 = r3882451 - r3882460;
double r3882462 = atan2(r3882450, r3882461);
double r3882463 = r3882442 + r3882462;
return r3882463;
}
double f(double lambda1, double phi1, double __attribute__((unused)) phi2, double delta, double theta) {
double r3882464 = phi1;
double r3882465 = cos(r3882464);
double r3882466 = theta;
double r3882467 = sin(r3882466);
double r3882468 = r3882465 * r3882467;
double r3882469 = delta;
double r3882470 = sin(r3882469);
double r3882471 = r3882468 * r3882470;
double r3882472 = cos(r3882469);
double r3882473 = r3882472 * r3882465;
double r3882474 = sin(r3882464);
double r3882475 = cos(r3882466);
double r3882476 = r3882470 * r3882475;
double r3882477 = r3882474 * r3882476;
double r3882478 = r3882473 - r3882477;
double r3882479 = r3882478 * r3882465;
double r3882480 = atan2(r3882471, r3882479);
double r3882481 = lambda1;
double r3882482 = r3882480 + r3882481;
return r3882482;
}



Bits error versus lambda1



Bits error versus phi1



Bits error versus phi2



Bits error versus delta



Bits error versus theta
Results
Initial program 0.2
rmApplied add-log-exp0.2
Applied add-log-exp0.2
Applied diff-log0.2
Simplified0.2
Taylor expanded around inf 0.2
Simplified0.1
Taylor expanded around 0 0.1
Simplified0.1
Final simplification0.1
herbie shell --seed 2019171
(FPCore (lambda1 phi1 phi2 delta theta)
:name "Destination given bearing on a great circle"
(+ lambda1 (atan2 (* (* (sin theta) (sin delta)) (cos phi1)) (- (cos delta) (* (sin phi1) (sin (asin (+ (* (sin phi1) (cos delta)) (* (* (cos phi1) (sin delta)) (cos theta))))))))))