Package org.apache.commons.math.fraction

Class Fraction

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<Fraction>, FieldElement<Fraction>
    public class Fraction
extends java.lang.Number
implements FieldElement<Fraction>, java.lang.Comparable<Fraction>, java.io.Serializable
    Representation of a rational number. implements Serializable since 2.0
    Since:
    1.1
    Version:
    $Revision: 990655 $ $Date: 2010-08-29 23:49:40 +0200 (dim. 29 août 2010) $
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      Fraction​(double value)
      Create a fraction given the double value.
      Fraction​(double value, double epsilon, int maxIterations)
      Create a fraction given the double value and maximum error allowed.
      Fraction​(double value, int maxDenominator)
      Create a fraction given the double value and maximum denominator.
      Fraction​(int num)
      Create a fraction from an int.
      Fraction​(int num, int den)
      Create a fraction given the numerator and denominator.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      Fraction abs()
      Returns the absolute value of this fraction.
      Fraction add​(int i)
      Add an integer to the fraction.
      Fraction add​(Fraction fraction)
      Adds the value of this fraction to another, returning the result in reduced form.
      int compareTo​(Fraction object)
      Compares this object to another based on size.
      Fraction divide​(int i)
      Divide the fraction by an integer.
      Fraction divide​(Fraction fraction)
      Divide the value of this fraction by another.
      double doubleValue()
      Gets the fraction as a double.
      boolean equals​(java.lang.Object other)
      Test for the equality of two fractions.
      float floatValue()
      Gets the fraction as a float.
      int getDenominator()
      Access the denominator.
      FractionField getField()
      Get the Field to which the instance belongs.
      int getNumerator()
      Access the numerator.
      static Fraction getReducedFraction​(int numerator, int denominator)
      Creates a Fraction instance with the 2 parts of a fraction Y/Z.
      int hashCode()
      Gets a hashCode for the fraction.
      int intValue()
      Gets the fraction as an int.
      long longValue()
      Gets the fraction as a long.
      Fraction multiply​(int i)
      Multiply the fraction by an integer.
      Fraction multiply​(Fraction fraction)
      Multiplies the value of this fraction by another, returning the result in reduced form.
      Fraction negate()
      Return the additive inverse of this fraction.
      Fraction reciprocal()
      Return the multiplicative inverse of this fraction.
      Fraction subtract​(int i)
      Subtract an integer from the fraction.
      Fraction subtract​(Fraction fraction)
      Subtracts the value of another fraction from the value of this one, returning the result in reduced form.
      java.lang.String toString()
      Returns the String representing this fraction, ie "num / dem" or just "num" if the denominator is one.

      • Methods inherited from class java.lang.Number

        byteValue, shortValue

      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    • Field Detail

      • TWO

        public static final Fraction TWO
        A fraction representing "2 / 1".

      • ONE

        public static final Fraction ONE
        A fraction representing "1".

      • ZERO

        public static final Fraction ZERO
        A fraction representing "0".

      • FOUR_FIFTHS

        public static final Fraction FOUR_FIFTHS
        A fraction representing "4/5".

      • ONE_FIFTH

        public static final Fraction ONE_FIFTH
        A fraction representing "1/5".

      • ONE_HALF

        public static final Fraction ONE_HALF
        A fraction representing "1/2".

      • ONE_QUARTER

        public static final Fraction ONE_QUARTER
        A fraction representing "1/4".

      • ONE_THIRD

        public static final Fraction ONE_THIRD
        A fraction representing "1/3".

      • THREE_FIFTHS

        public static final Fraction THREE_FIFTHS
        A fraction representing "3/5".

      • THREE_QUARTERS

        public static final Fraction THREE_QUARTERS
        A fraction representing "3/4".

      • TWO_FIFTHS

        public static final Fraction TWO_FIFTHS
        A fraction representing "2/5".

      • TWO_QUARTERS

        public static final Fraction TWO_QUARTERS
        A fraction representing "2/4".

      • TWO_THIRDS

        public static final Fraction TWO_THIRDS
        A fraction representing "2/3".

      • MINUS_ONE

        public static final Fraction MINUS_ONE
        A fraction representing "-1 / 1".

    • Constructor Detail

      • Fraction

        public Fraction​(double value,
                double epsilon,
                int maxIterations)
         throws FractionConversionException
        Create a fraction given the double value and maximum error allowed.

        References:

        Parameters:
        value - the double value to convert to a fraction.
        epsilon - maximum error allowed. The resulting fraction is within epsilon of value, in absolute terms.
        maxIterations - maximum number of convergents
        Throws:
        FractionConversionException - if the continued fraction failed to converge.

      • Fraction

        public Fraction​(double value,
                int maxDenominator)
         throws FractionConversionException
        Create a fraction given the double value and maximum denominator.

        References:

        Parameters:
        value - the double value to convert to a fraction.
        maxDenominator - The maximum allowed value for denominator
        Throws:
        FractionConversionException - if the continued fraction failed to converge

      • Fraction

        public Fraction​(int num)
        Create a fraction from an int. The fraction is num / 1.
        Parameters:
        num - the numerator.

      • Fraction

        public Fraction​(int num,
                int den)
        Create a fraction given the numerator and denominator. The fraction is reduced to lowest terms.
        Parameters:
        num - the numerator.
        den - the denominator.
        Throws:
        java.lang.ArithmeticException - if the denominator is zero

    • Method Detail

      • abs

        public Fraction abs()
        Returns the absolute value of this fraction.
        Returns:
        the absolute value.

      • compareTo

        public int compareTo​(Fraction object)
        Compares this object to another based on size.
        Specified by:
        compareTo in interface java.lang.Comparable<Fraction>
        Parameters:
        object - the object to compare to
        Returns:
        -1 if this is less than object, +1 if this is greater than object, 0 if they are equal.

      • doubleValue

        public double doubleValue()
        Gets the fraction as a double. This calculates the fraction as the numerator divided by denominator.
        Specified by:
        doubleValue in class java.lang.Number
        Returns:
        the fraction as a double

      • equals

        public boolean equals​(java.lang.Object other)
        Test for the equality of two fractions. If the lowest term numerator and denominators are the same for both fractions, the two fractions are considered to be equal.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        other - fraction to test for equality to this fraction
        Returns:
        true if two fractions are equal, false if object is null, not an instance of Fraction, or not equal to this fraction instance.

      • floatValue

        public float floatValue()
        Gets the fraction as a float. This calculates the fraction as the numerator divided by denominator.
        Specified by:
        floatValue in class java.lang.Number
        Returns:
        the fraction as a float

      • getDenominator

        public int getDenominator()
        Access the denominator.
        Returns:
        the denominator.

      • getNumerator

        public int getNumerator()
        Access the numerator.
        Returns:
        the numerator.

      • hashCode

        public int hashCode()
        Gets a hashCode for the fraction.
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        a hash code value for this object

      • intValue

        public int intValue()
        Gets the fraction as an int. This returns the whole number part of the fraction.
        Specified by:
        intValue in class java.lang.Number
        Returns:
        the whole number fraction part

      • longValue

        public long longValue()
        Gets the fraction as a long. This returns the whole number part of the fraction.
        Specified by:
        longValue in class java.lang.Number
        Returns:
        the whole number fraction part

      • negate

        public Fraction negate()
        Return the additive inverse of this fraction.
        Returns:
        the negation of this fraction.

      • reciprocal

        public Fraction reciprocal()
        Return the multiplicative inverse of this fraction.
        Returns:
        the reciprocal fraction

      • add

        public Fraction add​(Fraction fraction)

        Adds the value of this fraction to another, returning the result in reduced form. The algorithm follows Knuth, 4.5.1.

        Specified by:
        add in interface FieldElement<Fraction>
        Parameters:
        fraction - the fraction to add, must not be null
        Returns:
        a Fraction instance with the resulting values
        Throws:
        java.lang.IllegalArgumentException - if the fraction is null
        java.lang.ArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE

      • add

        public Fraction add​(int i)
        Add an integer to the fraction.
        Parameters:
        i - the integer to add.
        Returns:
        this + i

      • subtract

        public Fraction subtract​(Fraction fraction)

        Subtracts the value of another fraction from the value of this one, returning the result in reduced form.

        Specified by:
        subtract in interface FieldElement<Fraction>
        Parameters:
        fraction - the fraction to subtract, must not be null
        Returns:
        a Fraction instance with the resulting values
        Throws:
        java.lang.IllegalArgumentException - if the fraction is null
        java.lang.ArithmeticException - if the resulting numerator or denominator cannot be represented in an int.

      • subtract

        public Fraction subtract​(int i)
        Subtract an integer from the fraction.
        Parameters:
        i - the integer to subtract.
        Returns:
        this - i

      • multiply

        public Fraction multiply​(Fraction fraction)

        Multiplies the value of this fraction by another, returning the result in reduced form.

        Specified by:
        multiply in interface FieldElement<Fraction>
        Parameters:
        fraction - the fraction to multiply by, must not be null
        Returns:
        a Fraction instance with the resulting values
        Throws:
        java.lang.IllegalArgumentException - if the fraction is null
        java.lang.ArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE

      • multiply

        public Fraction multiply​(int i)
        Multiply the fraction by an integer.
        Parameters:
        i - the integer to multiply by.
        Returns:
        this * i

      • divide

        public Fraction divide​(Fraction fraction)

        Divide the value of this fraction by another.

        Specified by:
        divide in interface FieldElement<Fraction>
        Parameters:
        fraction - the fraction to divide by, must not be null
        Returns:
        a Fraction instance with the resulting values
        Throws:
        java.lang.IllegalArgumentException - if the fraction is null
        java.lang.ArithmeticException - if the fraction to divide by is zero
        java.lang.ArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE

      • divide

        public Fraction divide​(int i)
        Divide the fraction by an integer.
        Parameters:
        i - the integer to divide by.
        Returns:
        this * i

      • getReducedFraction

        public static Fraction getReducedFraction​(int numerator,
                                          int denominator)

        Creates a Fraction instance with the 2 parts of a fraction Y/Z.

        Any negative signs are resolved to be on the numerator.

        Parameters:
        numerator - the numerator, for example the three in 'three sevenths'
        denominator - the denominator, for example the seven in 'three sevenths'
        Returns:
        a new fraction instance, with the numerator and denominator reduced
        Throws:
        java.lang.ArithmeticException - if the denominator is zero

      • toString

        public java.lang.String toString()

        Returns the String representing this fraction, ie "num / dem" or just "num" if the denominator is one.

        Overrides:
        toString in class java.lang.Object
        Returns:
        a string representation of the fraction.
        See Also:
        Object.toString()