com.vividsolutions.jts.index.quadtree
Class DoubleBits

java.lang.Object
  com.vividsolutions.jts.index.quadtree.DoubleBits

public class DoubleBits

extends java.lang.Object

DoubleBits manipulates Double numbers by using bit manipulation and bit-field extraction. For some operations (such as determining the exponent) this is more accurate than using mathematical operations (which suffer from round-off error).

The algorithms and constants in this class apply only to IEEE-754 double-precision floating point format.

Version:

1.7

Field Summary

static int

EXPONENT_BIAS

Constructor Summary

DoubleBits(double x)

Method Summary

int	biasedExponent() Determines the exponent for the number
static int	exponent(double d)
int	getBit(int i)
double	getDouble()
int	getExponent() Determines the exponent for the number
static double	maximumCommonMantissa(double d1, double d2)
int	numCommonMantissaBits(DoubleBits db) This computes the number of common most-significant bits in the mantissa.
static double	powerOf2(int exp)
static java.lang.String	toBinaryString(double d)
java.lang.String	toString() A representation of the Double bits formatted for easy readability
static double	truncateToPowerOfTwo(double d)
void	zeroLowerBits(int nBits)

Methods inherited from class java.lang.Object

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

Field Detail

EXPONENT_BIAS

public static final int EXPONENT_BIAS

See Also:

Constant Field Values

Constructor Detail

DoubleBits

public DoubleBits(double x)

Method Detail

powerOf2

public static double powerOf2(int exp)

exponent

public static int exponent(double d)

truncateToPowerOfTwo

public static double truncateToPowerOfTwo(double d)

toBinaryString

public static java.lang.String toBinaryString(double d)

maximumCommonMantissa

public static double maximumCommonMantissa(double d1,
                                           double d2)

getDouble

public double getDouble()

biasedExponent

public int biasedExponent()

Determines the exponent for the number

getExponent

public int getExponent()

Determines the exponent for the number

zeroLowerBits

public void zeroLowerBits(int nBits)

getBit

public int getBit(int i)

numCommonMantissaBits

public int numCommonMantissaBits(DoubleBits db)

This computes the number of common most-significant bits in the mantissa. It does not count the hidden bit, which is always 1. It does not determine whether the numbers have the same exponent - if they do not, the value computed by this function is meaningless.

Parameters:

db -

Returns:

the number of common most-significant mantissa bits

toString

public java.lang.String toString()

A representation of the Double bits formatted for easy readability