Package org.apache.lucene.util

Class SloppyMath

  • public class SloppyMath
extends java.lang.Object
    Math functions that trade off accuracy for speed.

    • Constructor Summary

      Constructors 
      Constructor Description
      SloppyMath()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      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

        equals, 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 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:
        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:

        • 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:
        Math.asin(double)

      • earthDiameter

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