net.sf.jagg
Class DoubleDouble

java.lang.Object
  net.sf.jagg.DoubleDouble

All Implemented Interfaces:

java.lang.Comparable<DoubleDouble>

public class DoubleDouble
extends java.lang.Object
implements java.lang.Comparable<DoubleDouble>

A DoubleDouble is used when extra precision is necessary to cut way down on floating point errors.

Since:

0.4.0

Author:

Randy Gettman

Field Summary

static DoubleDouble	NaN The DoubleDouble NaN (Not a Number), immutable.
static DoubleDouble	ZERO The DoubleDouble zero, immutable.

Constructor Summary

DoubleDouble()
Create a DoubleDouble, initialized to zero.

DoubleDouble(double d)
Create a DoubleDouble from a double.

DoubleDouble(DoubleDouble dd)
Copy constructor.

DoubleDouble(double hi, double lo)
Create a DoubleDouble from high and low parts.

Method Summary

void	addToSelf(double d) Adds a double to this.
void	addToSelf(DoubleDouble dd) Adds another DoubleDouble to this one.
int	compareTo(DoubleDouble other) Returns an integer less than zero, equal to zero, or greater than zero, depending on whether this compares less than, equal to, or greather than another DoubleDouble.
void	divideSelfBy(double d) Divides self by a double.
void	divideSelfBy(DoubleDouble dd) Divides self by a DoubleDouble.
double	doubleValue() Returns the double that is closest in value to this DoubleDouble.
double	getLow() Returns the low-order portion of this DoubleDouble.
boolean	isNaN() Returns whether this DoubleDouble is NaN.
void	multiplySelfBy(double d) Multiplies self by a double.
void	multiplySelfBy(DoubleDouble dd) Multiplies self by another DoubleDouble.
void	negateSelf() Negate each part.
void	nthRootSelf(long n) Takes the nth root of self.
void	powSelf(long exponent) Raise self to an integer exponent.
void	reset() Sets this DoubleDouble equal to zero.
void	sqrtSelf() Takes the square root of self.
void	squareSelf() Squares self.
void	subtractFromSelf(double d) Subtracts a double from this.
void	subtractFromSelf(DoubleDouble dd) Subtracts another DoubleDouble from this one.

Methods inherited from class java.lang.Object

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

Field Detail

NaN

public static final DoubleDouble NaN

The DoubleDouble NaN (Not a Number), immutable.

ZERO

public static final DoubleDouble ZERO

The DoubleDouble zero, immutable.

Constructor Detail

DoubleDouble

public DoubleDouble()

Create a DoubleDouble, initialized to zero.

DoubleDouble

public DoubleDouble(double d)

Create a DoubleDouble from a double.

Parameters:

d - A double.

DoubleDouble

public DoubleDouble(double hi,
                    double lo)

Create a DoubleDouble from high and low parts.

Parameters:

hi - The high-order part.

lo - The low-order part.

DoubleDouble

public DoubleDouble(DoubleDouble dd)

Copy constructor.

Parameters:

dd - Another DoubleDouble.

Method Detail

reset

public void reset()

Sets this DoubleDouble equal to zero.

doubleValue

public double doubleValue()

Returns the double that is closest in value to this DoubleDouble.

Returns:

A double (the high portion of this DoubleDouble).

getLow

public double getLow()

Returns the low-order portion of this DoubleDouble.

Returns:

The low-order portion of this DoubleDouble.

isNaN

public boolean isNaN()

Returns whether this DoubleDouble is NaN.

Returns:

Whether this DoubleDouble is NaN.

addToSelf

public void addToSelf(DoubleDouble dd)

Adds another DoubleDouble to this one.

Parameters:

dd - Another DoubleDouble.

addToSelf

public void addToSelf(double d)

Adds a double to this. Algorithm is based on "Algorithms for Quad-Double Precision Floating Point Arithmetic" by Hida, Li, and Bailey, 2000, Berkeley.

Parameters:

d - A double.

subtractFromSelf

public void subtractFromSelf(DoubleDouble dd)

Subtracts another DoubleDouble from this one.

Parameters:

dd - Another DoubleDouble.

subtractFromSelf

public void subtractFromSelf(double d)

Subtracts a double from this.

Parameters:

d - A double.

negateSelf

public void negateSelf()

Negate each part. NaNs aren't negated (or negatable). The negation of NaN is NaN.

multiplySelfBy

public void multiplySelfBy(DoubleDouble dd)

Multiplies self by another DoubleDouble.

Parameters:

dd - Another DoubleDouble.

multiplySelfBy

public void multiplySelfBy(double d)

Multiplies self by a double.

Parameters:

d - A double.

squareSelf

public void squareSelf()

Squares self.

divideSelfBy

public void divideSelfBy(DoubleDouble dd)

Divides self by a DoubleDouble.

Parameters:

dd - Another DoubleDouble.

divideSelfBy

public void divideSelfBy(double d)

Divides self by a double.

Parameters:

d - A double.

sqrtSelf

public void sqrtSelf()

Takes the square root of self.

powSelf

public void powSelf(long exponent)

Raise self to an integer exponent.

Parameters:

exponent - The exponent.

nthRootSelf

public void nthRootSelf(long n)

Takes the nth root of self.

Parameters:

n - The root.

compareTo

public int compareTo(DoubleDouble other)

Returns an integer less than zero, equal to zero, or greater than zero, depending on whether this compares less than, equal to, or greather than another DoubleDouble.

Specified by:

compareTo in interface java.lang.Comparable<DoubleDouble>

Parameters:

other - Another DoubleDouble.

Returns:

An integer less than zero, equal to zero, or greater than zero, depending on whether this compares less than, equal to, or greather than another DoubleDouble.