DistancePrimitives.java

import java.util.Calendar;

public class DistancePrimitives {
        //note: I'm using floats since that's what I did in Lisp.
        //The program runs in about the same time using doubles

	private static final float PI = (float)Math.PI;
	private static final int RADIUS = 6371;
	
	public static float degreeToRadian(float degree) {
		return degree * (PI/180f);
	}
	
	public static float distance(float latA, float lngA, float latB, float lngB) {
		final float latAr = degreeToRadian(latA);
		final float lngAr = degreeToRadian(lngA);
		final float latBr = degreeToRadian(latB);
		final float lngBr = degreeToRadian(lngB);
		
		final float deltaLat = latBr - latAr;
		final float deltaLng = lngBr - lngAr;
		
		return (float) (RADIUS * 2 * Math.asin(Math.sqrt(
					Math.pow(Math.sin(deltaLat/2), 2)
					+ Math.cos(latAr) * Math.cos(latBr) * 
					Math.pow(Math.sin(deltaLng/2), 2))));
	}
	
	public static void main(String[] args) {
		float increment = 2.5f;
		long start = Calendar.getInstance().getTimeInMillis();
		for(float latA = -90; latA<= 90; latA=latA+increment) {
			for(float lngA = -180; lngA<= 180; lngA=lngA+increment) {
				for(float latB = -90; latB<= 90; latB=latB+increment) {
					for(float lngB = -180; lngB<= 180; lngB=lngB+increment) {
						distance(latA, lngA, latB, lngB);
					}
				}
			}
		}
		long end = Calendar.getInstance().getTimeInMillis();
		
		System.out.println("Runtime was: " + (end-start) + " Milliseconds");
	}
}