com.revolsys.jts.index

Class DoubleBits

java.lang.Object

com.revolsys.jts.index.DoubleBits

public class DoubleBits
extends 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

Fields

Modifier and Type	Field and Description
static int	EXPONENT_BIAS

Constructor Summary

Constructors

Constructor and Description
DoubleBits(double x)

Method Summary

Methods

Modifier and Type	Method and Description
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 String	toBinaryString(double d)
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

exponent

public static int exponent(double d)

maximumCommonMantissa

public static double maximumCommonMantissa(double d1,
                           double d2)

powerOf2

public static double powerOf2(int exp)

toBinaryString

public static String toBinaryString(double d)

truncateToPowerOfTwo

public static double truncateToPowerOfTwo(double d)

biasedExponent

public int biasedExponent()

Determines the exponent for the number

getBit

public int getBit(int i)

getDouble

public double getDouble()

getExponent

public int getExponent()

Determines the exponent for the number

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 String toString()

A representation of the Double bits formatted for easy readability

Overrides:

toString in class Object

zeroLowerBits

public void zeroLowerBits(int nBits)