Haversine Formula (shown below) expressed in terms of a two-argument inverse tangent function to calculate the great circle distance between two points on the Earth
####################################################################################### dlon = lon2 - lon1 , dlat = lat2 - lat1 , a = (sin(dlat/2))^2 + cos(lat1) * cos(lat2) * (sin(dlon/2))^2 , c = 2 * atan2( sqrt(a), sqrt(1-a) ) , d = R * c (where R is the radius of the Earth) ########################################################################################## --------------------------------use---------------------------------------------
model.compile(optimizer=optimizer, loss=[Haversine(R)])