Package org.apache.commons.math.fraction

Class Fraction

java.lang.Object
java.lang.Number
org.apache.commons.math.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 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".

  • 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

      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:
      ArithmeticException - 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.
      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:
      IllegalArgumentException - if the fraction is null
      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:
      IllegalArgumentException - if the fraction is null
      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:
      IllegalArgumentException - if the fraction is null
      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:
      IllegalArgumentException - if the fraction is null
      ArithmeticException - if the fraction to divide by is zero
      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:
      ArithmeticException - 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