Class Fraction

java.lang.Object
java.lang.Number
org.apache.commons.math3.fraction.Fraction
All Implemented Interfaces:
Serializable, Comparable<Fraction>, FieldElement<Fraction>

public class Fraction extends Number implements FieldElement<Fraction>, Comparable<Fraction>, Serializable
Representation of a rational number. implements Serializable since 2.0
Since:
1.1
See Also:
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private static final double
    The default epsilon used for convergence.
    private final int
    The denominator.
    static final Fraction
    A fraction representing "4/5".
    static final Fraction
    A fraction representing "-1 / 1".
    private final int
    The numerator.
    static final Fraction
    A fraction representing "1".
    static final Fraction
    A fraction representing "1/5".
    static final Fraction
    A fraction representing "1/2".
    static final Fraction
    A fraction representing "1/4".
    static final Fraction
    A fraction representing "1/3".
    private static final long
    Serializable version identifier
    static final Fraction
    A fraction representing "3/5".
    static final Fraction
    A fraction representing "3/4".
    static final Fraction
    A fraction representing "2 / 1".
    static final Fraction
    A fraction representing "2/5".
    static final Fraction
    A fraction representing "2/4".
    static final Fraction
    A fraction representing "2/3".
    static final Fraction
    A fraction representing "0".
  • Constructor Summary

    Constructors
    Modifier
    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.
    private
    Fraction(double value, double epsilon, int maxDenominator, int maxIterations)
    Create a fraction given the double value and either the maximum error allowed or the maximum number of denominator digits.
     
    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

    Modifier and Type
    Method
    Description
    abs()
    Returns the absolute value of this fraction.
    add(int i)
    Add an integer to the fraction.
    add(Fraction fraction)
    Adds the value of this fraction to another, returning the result in reduced form.
    private Fraction
    addSub(Fraction fraction, boolean isAdd)
    Implement add and subtract using algorithm described in Knuth 4.5.1.
    int
    Compares this object to another based on size.
    divide(int i)
    Divide the fraction by an integer.
    divide(Fraction fraction)
    Divide the value of this fraction by another.
    double
    Gets the fraction as a double.
    boolean
    equals(Object other)
    Test for the equality of two fractions.
    float
    Gets the fraction as a float.
    int
    Access the denominator.
    Get the Field to which the instance belongs.
    int
    Access the numerator.
    static Fraction
    getReducedFraction(int numerator, int denominator)
    Creates a Fraction instance with the 2 parts of a fraction Y/Z.
    int
    Gets a hashCode for the fraction.
    int
    Gets the fraction as an int.
    long
    Gets the fraction as a long.
    multiply(int i)
    Multiply the fraction by an integer.
    multiply(Fraction fraction)
    Multiplies the value of this fraction by another, returning the result in reduced form.
    Return the additive inverse of this fraction.
    double
    Gets the fraction percentage as a double.
    Return the multiplicative inverse of this fraction.
    subtract(int i)
    Subtract an integer from the fraction.
    subtract(Fraction fraction)
    Subtracts the value of another fraction from the value of this one, returning the result in reduced form.
    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 Details

    • 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".
    • serialVersionUID

      private static final long serialVersionUID
      Serializable version identifier
      See Also:
    • DEFAULT_EPSILON

      private static final double DEFAULT_EPSILON
      The default epsilon used for convergence.
      See Also:
    • denominator

      private final int denominator
      The denominator.
    • numerator

      private final int numerator
      The numerator.
  • Constructor Details

    • Fraction

      public Fraction(double value) throws FractionConversionException
      Create a fraction given the double value.
      Parameters:
      value - the double value to convert to a fraction.
      Throws:
      FractionConversionException - if the continued fraction failed to converge.
    • 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

      private Fraction(double value, double epsilon, int maxDenominator, int maxIterations) throws FractionConversionException
      Create a fraction given the double value and either the maximum error allowed or the maximum number of denominator digits.

      NOTE: This constructor is called with EITHER - a valid epsilon value and the maxDenominator set to Integer.MAX_VALUE (that way the maxDenominator has no effect). OR - a valid maxDenominator value and the epsilon value set to zero (that way epsilon only has effect if there is an exact match before the maxDenominator value is reached).

      It has been done this way so that the same code can be (re)used for both scenarios. However this could be confusing to users if it were part of the public API and this constructor should therefore remain PRIVATE.

      See JIRA issue ticket MATH-181 for more details: https://issues.apache.org/jira/browse/MATH-181
      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.
      maxDenominator - maximum denominator value allowed.
      maxIterations - maximum number of convergents
      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:
      MathArithmeticException - if the denominator is zero
  • Method Details

    • 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 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 Number
      Returns:
      the fraction as a double
    • equals

      public boolean equals(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 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 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 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 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 Number
      Returns:
      the whole number fraction part
    • negate

      public Fraction negate()
      Return the additive inverse of this fraction.
      Specified by:
      negate in interface FieldElement<Fraction>
      Returns:
      the negation of this fraction.
    • reciprocal

      public Fraction reciprocal()
      Return the multiplicative inverse of this fraction.
      Specified by:
      reciprocal in interface FieldElement<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:
      NullArgumentException - if the fraction is null
      MathArithmeticException - 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:
      NullArgumentException - if the fraction is null
      MathArithmeticException - 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
    • addSub

      private Fraction addSub(Fraction fraction, boolean isAdd)
      Implement add and subtract using algorithm described in Knuth 4.5.1.
      Parameters:
      fraction - the fraction to subtract, must not be null
      isAdd - true to add, false to subtract
      Returns:
      a Fraction instance with the resulting values
      Throws:
      NullArgumentException - if the fraction is null
      MathArithmeticException - if the resulting numerator or denominator cannot be represented in an int.
    • 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:
      NullArgumentException - if the fraction is null
      MathArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE
    • multiply

      public Fraction multiply(int i)
      Multiply the fraction by an integer.
      Specified by:
      multiply in interface FieldElement<Fraction>
      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:
      IllegalArgumentException - if the fraction is null
      MathArithmeticException - if the fraction to divide by is zero
      MathArithmeticException - 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
    • percentageValue

      public double percentageValue()

      Gets the fraction percentage as a double. This calculates the fraction as the numerator divided by denominator multiplied by 100.

      Returns:
      the fraction percentage as a double.
    • 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:
      MathArithmeticException - if the denominator is zero
    • toString

      public String toString()

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

      Overrides:
      toString in class Object
      Returns:
      a string representation of the fraction.
      See Also:
    • getField

      public FractionField getField()
      Get the Field to which the instance belongs.
      Specified by:
      getField in interface FieldElement<Fraction>
      Returns:
      Field to which the instance belongs