Package org.apache.lucene.util

Class SloppyMath

java.lang.Object
org.apache.lucene.util.SloppyMath
public class SloppyMath extends Object
Math functions that trade off accuracy for speed.

  • Constructor Summary

    Constructors
    Constructor
    Description
    SloppyMath()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    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
    earthDiameter(double latitude)
    Return an approximate value of the diameter of the earth at the given latitude, in kilometers.
    static double
    haversin(double lat1, double lon1, double lat2, double lon2)
    Returns the distance in kilometers between two points specified in decimal degrees (latitude/longitude).

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • SloppyMath

      public SloppyMath()

  • Method Details

    • haversin

      public static double haversin(double lat1, double lon1, double lat2, double lon2)
      Returns the distance in kilometers between two points specified in decimal degrees (latitude/longitude).
      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:

      • If the argument is NaN or an infinity, then the result is NaN.
      Parameters:
      a - an angle, in radians.
      Returns:
      the cosine of the argument.
      See Also:

    • 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:

      • If the argument is NaN or its absolute value is greater than 1, then the result is NaN.
      Parameters:
      a - the value whose arc sine is to be returned.
      Returns:
      arc sine of the argument
      See Also:

    • earthDiameter

      public static double earthDiameter(double latitude)
      Return an approximate value of the diameter of the earth at the given latitude, in kilometers.