Use the --timeout flag to change the timeout.
R \cdot \sqrt{\left(\left(\lambda_1 - \lambda_2\right) \cdot \cos \left(\frac{\phi_1 + \phi_2}{2}\right)\right) \cdot \left(\left(\lambda_1 - \lambda_2\right) \cdot \cos \left(\frac{\phi_1 + \phi_2}{2}\right)\right) + \left(\phi_1 - \phi_2\right) \cdot \left(\phi_1 - \phi_2\right)}double f(double R, double lambda1, double lambda2, double phi1, double phi2) {
double r118975835 = R;
double r118975836 = lambda1;
double r118975837 = lambda2;
double r118975838 = r118975836 - r118975837;
double r118975839 = phi1;
double r118975840 = phi2;
double r118975841 = r118975839 + r118975840;
double r118975842 = 2.0;
double r118975843 = r118975841 / r118975842;
double r118975844 = cos(r118975843);
double r118975845 = r118975838 * r118975844;
double r118975846 = r118975845 * r118975845;
double r118975847 = r118975839 - r118975840;
double r118975848 = r118975847 * r118975847;
double r118975849 = r118975846 + r118975848;
double r118975850 = sqrt(r118975849);
double r118975851 = r118975835 * r118975850;
return r118975851;
}
herbie shell --seed 2019172
(FPCore (R lambda1 lambda2 phi1 phi2)
:name "Equirectangular approximation to distance on a great circle"
(* R (sqrt (+ (* (* (- lambda1 lambda2) (cos (/ (+ phi1 phi2) 2.0))) (* (- lambda1 lambda2) (cos (/ (+ phi1 phi2) 2.0)))) (* (- phi1 phi2) (- phi1 phi2))))))