\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)}\lambda_1 + \tan^{-1}_* \frac{\left(\sin theta \cdot \sin delta\right) \cdot \cos \phi_1}{\frac{{\left(\cos delta\right)}^{3} - {\left(\sin \phi_1\right)}^{3} \cdot {\left(\sin \phi_1 \cdot \cos delta + \cos theta \cdot \left(\sin delta \cdot \cos \phi_1\right)\right)}^{3}}{\cos delta \cdot \cos delta + \left(\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)\right) \cdot \left(\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)\right)}}double code(double lambda1, double phi1, double phi2, double delta, double theta) {
return ((double) (lambda1 + ((double) atan2(((double) (((double) (((double) sin(theta)) * ((double) sin(delta)))) * ((double) cos(phi1)))), ((double) (((double) cos(delta)) - ((double) (((double) sin(phi1)) * ((double) sin(((double) asin(((double) (((double) (((double) sin(phi1)) * ((double) cos(delta)))) + ((double) (((double) (((double) cos(phi1)) * ((double) sin(delta)))) * ((double) cos(theta))))))))))))))))));
}
double code(double lambda1, double phi1, double phi2, double delta, double theta) {
return ((double) (lambda1 + ((double) atan2(((double) (((double) (((double) sin(theta)) * ((double) sin(delta)))) * ((double) cos(phi1)))), (((double) (((double) pow(((double) cos(delta)), 3.0)) - ((double) (((double) pow(((double) sin(phi1)), 3.0)) * ((double) pow(((double) (((double) (((double) sin(phi1)) * ((double) cos(delta)))) + ((double) (((double) cos(theta)) * ((double) (((double) sin(delta)) * ((double) cos(phi1)))))))), 3.0)))))) / ((double) (((double) (((double) cos(delta)) * ((double) cos(delta)))) + ((double) (((double) (((double) sin(phi1)) * ((double) sin(((double) asin(((double) (((double) (((double) sin(phi1)) * ((double) cos(delta)))) + ((double) (((double) (((double) cos(phi1)) * ((double) sin(delta)))) * ((double) cos(theta)))))))))))) * ((double) (((double) cos(delta)) + ((double) (((double) sin(phi1)) * ((double) sin(((double) asin(((double) (((double) (((double) sin(phi1)) * ((double) cos(delta)))) + ((double) (((double) (((double) cos(phi1)) * ((double) sin(delta)))) * ((double) cos(theta)))))))))))))))))))))));
}



Bits error versus lambda1



Bits error versus phi1



Bits error versus phi2



Bits error versus delta



Bits error versus theta
Results
Initial program 0.1
rmApplied flip3--0.2
Simplified0.2
Taylor expanded around inf 0.2
Final simplification0.2
herbie shell --seed 2020182
(FPCore (lambda1 phi1 phi2 delta theta)
:name "Destination given bearing on a great circle"
:precision binary64
(+ lambda1 (atan2 (* (* (sin theta) (sin delta)) (cos phi1)) (- (cos delta) (* (sin phi1) (sin (asin (+ (* (sin phi1) (cos delta)) (* (* (cos phi1) (sin delta)) (cos theta))))))))))