org.apache.lucene.util
Class SloppyMath

java.lang.Object
  extended by org.apache.lucene.util.SloppyMath

public class SloppyMath
extends Object

Math functions that trade off accuracy for speed.


Constructor Summary
SloppyMath()
           
 
Method Summary
static double asin(double a)
          Returns the arc sine of a value.
static double cos(double a)
          Returns the trigonometric cosine of an angle.
static double haversin(double lat1, double lon1, double lat2, double lon2)
          Returns the distance between two points in decimal degrees.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SloppyMath

public SloppyMath()
Method Detail

haversin

public static double haversin(double lat1,
                              double lon1,
                              double lat2,
                              double lon2)
Returns the distance between two points in decimal degrees.

Parameters:
lat1 - Latitude of the first point.
lon1 - Longitude of the first point.
lat2 - Latitude of the second point.
lon2 - Longitude of the second point.
Returns:
distance in kilometers.

cos

public static double cos(double a)
Returns the trigonometric cosine of an angle.

Error is around 1E-15.

Special cases:

Parameters:
a - an angle, in radians.
Returns:
the cosine of the argument.
See Also:
Math.cos(double)

asin

public static double asin(double a)
Returns the arc sine of a value.

The returned angle is in the range -pi/2 through pi/2. Error is around 1E-7.

Special cases:

Parameters:
a - the value whose arc sine is to be returned.
Returns:
arc sine of the argument
See Also:
Math.asin(double)


Copyright © 2000-2013 Apache Software Foundation. All Rights Reserved.