Package cds.healpix.common.math

Class FastMath

  • public final class FastMath
extends java.lang.Object
    Comes from the Apache FastMath class, and is thus under the Apache licence.
    Author:
    F.-X. Pineau

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static double SAFE_MIN  

    • Constructor Summary

      Constructors 
      Constructor Description
      FastMath()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static double acos​(double x)
      Compute the arc cosine of a number.
      static double asin​(double x)
      Compute the arc sine of a number.
      static double atan​(double x)
      Arctangent function
      static double copySign​(double magnitude, double sign)
      Returns the first argument with the sign of the second argument.
      static double cosQ​(double xa)
      Compute cosine in the first quadrant by subtracting input from PI/2 and then calling sinQ.
      static double sinQ​(double xa, double xb)
      Compute sine over the first quadrant (0 < x < pi/2).
      static double sqrt​(double a)
      Compute the square root of a number.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • FastMath

        public FastMath()

    • Method Detail

      • sinQ

        public static double sinQ​(double xa,
                          double xb)
        Compute sine over the first quadrant (0 < x < pi/2). Use combination of table lookup and rational polynomial expansion.
        Parameters:
        xa - number from which sine is requested
        xb - second param
        Returns:
        sin(xa + xb)

      • cosQ

        public static double cosQ​(double xa)
        Compute cosine in the first quadrant by subtracting input from PI/2 and then calling sinQ. This is more accurate as the input approaches PI/2.
        Parameters:
        xa - number from which cosine is requested
        Returns:
        cos(xa + xb)

      • asin

        public static double asin​(double x)
        Compute the arc sine of a number.
        Parameters:
        x - number on which evaluation is done
        Returns:
        arc sine of x

      • atan

        public static double atan​(double x)
        Arctangent function
        Parameters:
        x - a number
        Returns:
        atan(x)

      • acos

        public static double acos​(double x)
        Compute the arc cosine of a number.
        Parameters:
        x - number on which evaluation is done
        Returns:
        arc cosine of x

      • sqrt

        public static double sqrt​(double a)
        Compute the square root of a number.

        Note: this implementation currently delegates to Math.sqrt(double)

        Parameters:
        a - number on which evaluation is done
        Returns:
        square root of a

      • copySign

        public static double copySign​(double magnitude,
                              double sign)
        Returns the first argument with the sign of the second argument. A NaN sign argument is treated as positive.
        Parameters:
        magnitude - the value to return
        sign - the sign for the returned value
        Returns:
        the magnitude with the same sign as the sign argument