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 r116737163 = R;
double r116737164 = lambda1;
double r116737165 = lambda2;
double r116737166 = r116737164 - r116737165;
double r116737167 = phi1;
double r116737168 = phi2;
double r116737169 = r116737167 + r116737168;
double r116737170 = 2.0;
double r116737171 = r116737169 / r116737170;
double r116737172 = cos(r116737171);
double r116737173 = r116737166 * r116737172;
double r116737174 = r116737173 * r116737173;
double r116737175 = r116737167 - r116737168;
double r116737176 = r116737175 * r116737175;
double r116737177 = r116737174 + r116737176;
double r116737178 = sqrt(r116737177);
double r116737179 = r116737163 * r116737178;
return r116737179;
}
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))))))