JScience v4.3

org.jscience.mathematics.number
Class Rational

java.lang.Object
  extended by java.lang.Number
      extended by org.jscience.mathematics.number.Number<Rational>
          extended by org.jscience.mathematics.number.Rational
All Implemented Interfaces:
java.io.Serializable, java.lang.Comparable<Rational>, javolution.lang.Immutable, javolution.lang.Realtime, javolution.lang.ValueType, javolution.xml.XMLSerializable, Field<Rational>, GroupAdditive<Rational>, GroupMultiplicative<Rational>, Ring<Rational>, Structure<Rational>

public final class Rational
extends Number<Rational>
implements Field<Rational>

This class represents the ratio of two LargeInteger numbers.

Instances of this class are immutable and can be used to find exact solutions to linear equations with the Matrix class.

Version:
3.0, February 13, 2006
Author:
Jean-Marie Dautelle
See Also:
Wikipedia: Rational Numbers, Serialized Form

Field Summary
static Rational ONE
          The Rational representing the multiplicative identity.
static Rational ZERO
          The Rational representing the additive identity.
 
Method Summary
 Rational abs()
          Returns the absolute value of this rational number.
 int compareTo(Rational that)
          Compares two rational number numerically.
 Rational copy()
          Returns a copy of this number allocated by the calling thread (possibly on the stack).
 Rational divide(Rational that)
          Returns this rational number divided by the one specified.
 double doubleValue()
          Returns the value of this rational number as a double.
 boolean equals(java.lang.Object that)
          Compares this rational number against the specified object.
 LargeInteger getDividend()
          Returns the smallest dividend of the fraction representing this rational number.
 LargeInteger getDivisor()
          Returns the smallest divisor of the fraction representing this rational (always positive).
 int hashCode()
          Returns the hash code for this rational number.
 Rational inverse()
          Returns the inverse of this rational number.
 boolean isLargerThan(Rational that)
          Compares the absolute value of two rational numbers.
 boolean isNegative()
          Indicates if this rational number is less than zero.
 boolean isPositive()
          Indicates if this rational number is greater than zero.
 boolean isZero()
          Indicates if this rational number is equal to zero.
 long longValue()
          Returns the value of this rational number as a long.
 Rational minus(Rational that)
          Returns the difference between this rational number and the one specified.
 Rational opposite()
          Returns the opposite of this rational number.
 Rational plus(Rational that)
          Returns the sum of this rational number with the one specified.
 LargeInteger round()
          Returns the closest integer value to this rational number.
 Rational times(long multiplier)
          Returns the product of this rational number with the specified long multiplier.
 Rational times(Rational that)
          Returns the product of this rational number with the one specified.
 javolution.text.Text toText()
          Returns the decimal text representation of this number.
static Rational valueOf(java.lang.CharSequence chars)
          Returns the rational number for the specified character sequence.
static Rational valueOf(LargeInteger dividend, LargeInteger divisor)
          Returns the rational number for the specified large integer dividend and divisor.
static Rational valueOf(long dividend, long divisor)
          Returns the rational number for the specified integer dividend and divisor.
 
Methods inherited from class org.jscience.mathematics.number.Number
byteValue, floatValue, intValue, isGreaterThan, isLessThan, pow, shortValue, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

ZERO

public static final Rational ZERO
The Rational representing the additive identity.


ONE

public static final Rational ONE
The Rational representing the multiplicative identity.

Method Detail

valueOf

public static Rational valueOf(long dividend,
                               long divisor)
Returns the rational number for the specified integer dividend and divisor.

Parameters:
dividend - the dividend value.
divisor - the divisor value.
Returns:
dividend / divisor
Throws:
java.lang.ArithmeticException - if divisor == 0

valueOf

public static Rational valueOf(LargeInteger dividend,
                               LargeInteger divisor)
Returns the rational number for the specified large integer dividend and divisor.

Parameters:
dividend - the dividend value.
divisor - the divisor value.
Returns:
dividend / divisor
Throws:
java.lang.ArithmeticException - if divisor.isZero()

valueOf

public static Rational valueOf(java.lang.CharSequence chars)
Returns the rational number for the specified character sequence.

Parameters:
chars - the character sequence.
Returns:
the corresponding rational number.

getDividend

public LargeInteger getDividend()
Returns the smallest dividend of the fraction representing this rational number.

Returns:
this rational dividend.

getDivisor

public LargeInteger getDivisor()
Returns the smallest divisor of the fraction representing this rational (always positive).

Returns:
this rational divisor.

round

public LargeInteger round()
Returns the closest integer value to this rational number.

Returns:
this rational rounded to the nearest integer.

opposite

public Rational opposite()
Returns the opposite of this rational number.

Specified by:
opposite in interface GroupAdditive<Rational>
Returns:
-this.

plus

public Rational plus(Rational that)
Returns the sum of this rational number with the one specified.

Specified by:
plus in interface GroupAdditive<Rational>
Parameters:
that - the rational number to be added.
Returns:
this + that.

minus

public Rational minus(Rational that)
Returns the difference between this rational number and the one specified.

Overrides:
minus in class Number<Rational>
Parameters:
that - the rational number to be subtracted.
Returns:
this - that.

times

public Rational times(long multiplier)
Returns the product of this rational number with the specified long multiplier.

Parameters:
multiplier - the long multiplier.
Returns:
this · multiplier.

times

public Rational times(Rational that)
Returns the product of this rational number with the one specified.

Specified by:
times in interface GroupMultiplicative<Rational>
Specified by:
times in interface Ring<Rational>
Parameters:
that - the rational number multiplier.
Returns:
this · that.

inverse

public Rational inverse()
Returns the inverse of this rational number.

Specified by:
inverse in interface GroupMultiplicative<Rational>
Returns:
1 / this.
Throws:
java.lang.ArithmeticException - if dividend.isZero()

divide

public Rational divide(Rational that)
Returns this rational number divided by the one specified.

Parameters:
that - the rational number divisor.
Returns:
this / that.
Throws:
java.lang.ArithmeticException - if that.equals(ZERO)

abs

public Rational abs()
Returns the absolute value of this rational number.

Returns:
|this|.

isZero

public boolean isZero()
Indicates if this rational number is equal to zero.

Returns:
this == 0

isPositive

public boolean isPositive()
Indicates if this rational number is greater than zero.

Returns:
this > 0

isNegative

public boolean isNegative()
Indicates if this rational number is less than zero.

Returns:
this < 0

isLargerThan

public boolean isLargerThan(Rational that)
Compares the absolute value of two rational numbers.

Specified by:
isLargerThan in class Number<Rational>
Parameters:
that - the rational number to be compared with.
Returns:
|this| > |that|

toText

public javolution.text.Text toText()
Returns the decimal text representation of this number.

Specified by:
toText in interface javolution.lang.Realtime
Specified by:
toText in class Number<Rational>
Returns:
the text representation of this number.

equals

public boolean equals(java.lang.Object that)
Compares this rational number against the specified object.

Specified by:
equals in class Number<Rational>
Parameters:
that - the object to compare with.
Returns:
true if the objects are the same; false otherwise.

hashCode

public int hashCode()
Returns the hash code for this rational number.

Specified by:
hashCode in class Number<Rational>
Returns:
the hash code value.

longValue

public long longValue()
Returns the value of this rational number as a long.

Specified by:
longValue in class Number<Rational>
Returns:
the numeric value represented by this rational after conversion to type long.

doubleValue

public double doubleValue()
Returns the value of this rational number as a double.

Specified by:
doubleValue in class Number<Rational>
Returns:
the numeric value represented by this rational after conversion to type double.

compareTo

public int compareTo(Rational that)
Compares two rational number numerically.

Specified by:
compareTo in interface java.lang.Comparable<Rational>
Specified by:
compareTo in class Number<Rational>
Parameters:
that - the rational number to compare with.
Returns:
-1, 0 or 1 as this rational number is numerically less than, equal to, or greater than that.

copy

public Rational copy()
Description copied from class: Number
Returns a copy of this number allocated by the calling thread (possibly on the stack).

Specified by:
copy in interface javolution.lang.ValueType
Specified by:
copy in class Number<Rational>
Returns:
an identical and independant copy of this number.

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