home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (BigFraction.java)

This example Java source code file (BigFraction.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bigdecimal, bigfraction, biginteger, fieldelement, four_fifths, fractionconversionexception, math, nullargumentexception, override, serializable, string, three_fifths, two_fifths, two_thirds, zero

The BigFraction.java Java example source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math3.fraction;

import java.io.Serializable;
import java.math.BigDecimal;
import java.math.BigInteger;

import org.apache.commons.math3.FieldElement;
import org.apache.commons.math3.exception.MathArithmeticException;
import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.exception.NullArgumentException;
import org.apache.commons.math3.exception.ZeroException;
import org.apache.commons.math3.exception.util.LocalizedFormats;
import org.apache.commons.math3.util.ArithmeticUtils;
import org.apache.commons.math3.util.FastMath;
import org.apache.commons.math3.util.MathUtils;

/**
 * Representation of a rational number without any overflow. This class is
 * immutable.
 *
 * @since 2.0
 */
public class BigFraction
    extends Number
    implements FieldElement<BigFraction>, Comparable, Serializable {

    /** A fraction representing "2 / 1". */
    public static final BigFraction TWO = new BigFraction(2);

    /** A fraction representing "1". */
    public static final BigFraction ONE = new BigFraction(1);

    /** A fraction representing "0". */
    public static final BigFraction ZERO = new BigFraction(0);

    /** A fraction representing "-1 / 1". */
    public static final BigFraction MINUS_ONE = new BigFraction(-1);

    /** A fraction representing "4/5". */
    public static final BigFraction FOUR_FIFTHS = new BigFraction(4, 5);

    /** A fraction representing "1/5". */
    public static final BigFraction ONE_FIFTH = new BigFraction(1, 5);

    /** A fraction representing "1/2". */
    public static final BigFraction ONE_HALF = new BigFraction(1, 2);

    /** A fraction representing "1/4". */
    public static final BigFraction ONE_QUARTER = new BigFraction(1, 4);

    /** A fraction representing "1/3". */
    public static final BigFraction ONE_THIRD = new BigFraction(1, 3);

    /** A fraction representing "3/5". */
    public static final BigFraction THREE_FIFTHS = new BigFraction(3, 5);

    /** A fraction representing "3/4". */
    public static final BigFraction THREE_QUARTERS = new BigFraction(3, 4);

    /** A fraction representing "2/5". */
    public static final BigFraction TWO_FIFTHS = new BigFraction(2, 5);

    /** A fraction representing "2/4". */
    public static final BigFraction TWO_QUARTERS = new BigFraction(2, 4);

    /** A fraction representing "2/3". */
    public static final BigFraction TWO_THIRDS = new BigFraction(2, 3);

    /** Serializable version identifier. */
    private static final long serialVersionUID = -5630213147331578515L;

    /** <code>BigInteger representation of 100. */
    private static final BigInteger ONE_HUNDRED = BigInteger.valueOf(100);

    /** The numerator. */
    private final BigInteger numerator;

    /** The denominator. */
    private final BigInteger denominator;

    /**
     * <p>
     * Create a {@link BigFraction} equivalent to the passed {@code BigInteger}, ie
     * "num / 1".
     * </p>
     *
     * @param num
     *            the numerator.
     */
    public BigFraction(final BigInteger num) {
        this(num, BigInteger.ONE);
    }

    /**
     * Create a {@link BigFraction} given the numerator and denominator as
     * {@code BigInteger}. The {@link BigFraction} is reduced to lowest terms.
     *
     * @param num the numerator, must not be {@code null}.
     * @param den the denominator, must not be {@code null}.
     * @throws ZeroException if the denominator is zero.
     * @throws NullArgumentException if either of the arguments is null
     */
    public BigFraction(BigInteger num, BigInteger den) {
        MathUtils.checkNotNull(num, LocalizedFormats.NUMERATOR);
        MathUtils.checkNotNull(den, LocalizedFormats.DENOMINATOR);
        if (den.signum() == 0) {
            throw new ZeroException(LocalizedFormats.ZERO_DENOMINATOR);
        }
        if (num.signum() == 0) {
            numerator   = BigInteger.ZERO;
            denominator = BigInteger.ONE;
        } else {

            // reduce numerator and denominator by greatest common denominator
            final BigInteger gcd = num.gcd(den);
            if (BigInteger.ONE.compareTo(gcd) < 0) {
                num = num.divide(gcd);
                den = den.divide(gcd);
            }

            // move sign to numerator
            if (den.signum() == -1) {
                num = num.negate();
                den = den.negate();
            }

            // store the values in the final fields
            numerator   = num;
            denominator = den;

        }
    }

    /**
     * Create a fraction given the double value.
     * <p>
     * This constructor behaves <em>differently from
     * {@link #BigFraction(double, double, int)}. It converts the double value
     * exactly, considering its internal bits representation. This works for all
     * values except NaN and infinities and does not requires any loop or
     * convergence threshold.
     * </p>
     * <p>
     * Since this conversion is exact and since double numbers are sometimes
     * approximated, the fraction created may seem strange in some cases. For example,
     * calling <code>new BigFraction(1.0 / 3.0) does not create
     * the fraction 1/3, but the fraction 6004799503160661 / 18014398509481984
     * because the double number passed to the constructor is not exactly 1/3
     * (this number cannot be stored exactly in IEEE754).
     * </p>
     * @see #BigFraction(double, double, int)
     * @param value the double value to convert to a fraction.
     * @exception MathIllegalArgumentException if value is NaN or infinite
     */
    public BigFraction(final double value) throws MathIllegalArgumentException {
        if (Double.isNaN(value)) {
            throw new MathIllegalArgumentException(LocalizedFormats.NAN_VALUE_CONVERSION);
        }
        if (Double.isInfinite(value)) {
            throw new MathIllegalArgumentException(LocalizedFormats.INFINITE_VALUE_CONVERSION);
        }

        // compute m and k such that value = m * 2^k
        final long bits     = Double.doubleToLongBits(value);
        final long sign     = bits & 0x8000000000000000L;
        final long exponent = bits & 0x7ff0000000000000L;
        long m              = bits & 0x000fffffffffffffL;
        if (exponent != 0) {
            // this was a normalized number, add the implicit most significant bit
            m |= 0x0010000000000000L;
        }
        if (sign != 0) {
            m = -m;
        }
        int k = ((int) (exponent >> 52)) - 1075;
        while (((m & 0x001ffffffffffffeL) != 0) && ((m & 0x1) == 0)) {
            m >>= 1;
            ++k;
        }

        if (k < 0) {
            numerator   = BigInteger.valueOf(m);
            denominator = BigInteger.ZERO.flipBit(-k);
        } else {
            numerator   = BigInteger.valueOf(m).multiply(BigInteger.ZERO.flipBit(k));
            denominator = BigInteger.ONE;
        }

    }

    /**
     * Create a fraction given the double value and maximum error allowed.
     * <p>
     * References:
     * <ul>
     * <li>
     * Continued Fraction</a> equations (11) and (22)-(26)
     * </ul>
     * </p>
     *
     * @param value
     *            the double value to convert to a fraction.
     * @param epsilon
     *            maximum error allowed. The resulting fraction is within
     *            <code>epsilon of value, in absolute terms.
     * @param maxIterations
     *            maximum number of convergents.
     * @throws FractionConversionException
     *             if the continued fraction failed to converge.
     * @see #BigFraction(double)
     */
    public BigFraction(final double value, final double epsilon,
                       final int maxIterations)
        throws FractionConversionException {
        this(value, epsilon, Integer.MAX_VALUE, maxIterations);
    }

    /**
     * Create a fraction given the double value and either the maximum error
     * allowed or the maximum number of denominator digits.
     * <p>
     *
     * 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).
     * </p>
     * <p>
     *
     * 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.
     * </p>
     *
     * See JIRA issue ticket MATH-181 for more details:
     *
     * https://issues.apache.org/jira/browse/MATH-181
     *
     * @param value
     *            the double value to convert to a fraction.
     * @param epsilon
     *            maximum error allowed. The resulting fraction is within
     *            <code>epsilon of value, in absolute terms.
     * @param maxDenominator
     *            maximum denominator value allowed.
     * @param maxIterations
     *            maximum number of convergents.
     * @throws FractionConversionException
     *             if the continued fraction failed to converge.
     */
    private BigFraction(final double value, final double epsilon,
                        final int maxDenominator, int maxIterations)
        throws FractionConversionException {
        long overflow = Integer.MAX_VALUE;
        double r0 = value;
        long a0 = (long) FastMath.floor(r0);

        if (FastMath.abs(a0) > overflow) {
            throw new FractionConversionException(value, a0, 1l);
        }

        // check for (almost) integer arguments, which should not go
        // to iterations.
        if (FastMath.abs(a0 - value) < epsilon) {
            numerator = BigInteger.valueOf(a0);
            denominator = BigInteger.ONE;
            return;
        }

        long p0 = 1;
        long q0 = 0;
        long p1 = a0;
        long q1 = 1;

        long p2 = 0;
        long q2 = 1;

        int n = 0;
        boolean stop = false;
        do {
            ++n;
            final double r1 = 1.0 / (r0 - a0);
            final long a1 = (long) FastMath.floor(r1);
            p2 = (a1 * p1) + p0;
            q2 = (a1 * q1) + q0;
            if ((p2 > overflow) || (q2 > overflow)) {
                // in maxDenominator mode, if the last fraction was very close to the actual value
                // q2 may overflow in the next iteration; in this case return the last one.
                if (epsilon == 0.0 && FastMath.abs(q1) < maxDenominator) {
                    break;
                }
                throw new FractionConversionException(value, p2, q2);
            }

            final double convergent = (double) p2 / (double) q2;
            if ((n < maxIterations) &&
                (FastMath.abs(convergent - value) > epsilon) &&
                (q2 < maxDenominator)) {
                p0 = p1;
                p1 = p2;
                q0 = q1;
                q1 = q2;
                a0 = a1;
                r0 = r1;
            } else {
                stop = true;
            }
        } while (!stop);

        if (n >= maxIterations) {
            throw new FractionConversionException(value, maxIterations);
        }

        if (q2 < maxDenominator) {
            numerator   = BigInteger.valueOf(p2);
            denominator = BigInteger.valueOf(q2);
        } else {
            numerator   = BigInteger.valueOf(p1);
            denominator = BigInteger.valueOf(q1);
        }
    }

    /**
     * Create a fraction given the double value and maximum denominator.
     * <p>
     * References:
     * <ul>
     * <li>
     * Continued Fraction</a> equations (11) and (22)-(26)
     * </ul>
     * </p>
     *
     * @param value
     *            the double value to convert to a fraction.
     * @param maxDenominator
     *            The maximum allowed value for denominator.
     * @throws FractionConversionException
     *             if the continued fraction failed to converge.
     */
    public BigFraction(final double value, final int maxDenominator)
        throws FractionConversionException {
        this(value, 0, maxDenominator, 100);
    }

    /**
     * <p>
     * Create a {@link BigFraction} equivalent to the passed {@code int}, ie
     * "num / 1".
     * </p>
     *
     * @param num
     *            the numerator.
     */
    public BigFraction(final int num) {
        this(BigInteger.valueOf(num), BigInteger.ONE);
    }

    /**
     * <p>
     * Create a {@link BigFraction} given the numerator and denominator as simple
     * {@code int}. The {@link BigFraction} is reduced to lowest terms.
     * </p>
     *
     * @param num
     *            the numerator.
     * @param den
     *            the denominator.
     */
    public BigFraction(final int num, final int den) {
        this(BigInteger.valueOf(num), BigInteger.valueOf(den));
    }

    /**
     * <p>
     * Create a {@link BigFraction} equivalent to the passed long, ie "num / 1".
     * </p>
     *
     * @param num
     *            the numerator.
     */
    public BigFraction(final long num) {
        this(BigInteger.valueOf(num), BigInteger.ONE);
    }

    /**
     * <p>
     * Create a {@link BigFraction} given the numerator and denominator as simple
     * {@code long}. The {@link BigFraction} is reduced to lowest terms.
     * </p>
     *
     * @param num
     *            the numerator.
     * @param den
     *            the denominator.
     */
    public BigFraction(final long num, final long den) {
        this(BigInteger.valueOf(num), BigInteger.valueOf(den));
    }

    /**
     * <p>
     * Creates a <code>BigFraction instance with the 2 parts of a fraction
     * Y/Z.
     * </p>
     *
     * <p>
     * Any negative signs are resolved to be on the numerator.
     * </p>
     *
     * @param numerator
     *            the numerator, for example the three in 'three sevenths'.
     * @param denominator
     *            the denominator, for example the seven in 'three sevenths'.
     * @return a new fraction instance, with the numerator and denominator
     *         reduced.
     * @throws ArithmeticException
     *             if the denominator is <code>zero.
     */
    public static BigFraction getReducedFraction(final int numerator,
                                                 final int denominator) {
        if (numerator == 0) {
            return ZERO; // normalize zero.
        }

        return new BigFraction(numerator, denominator);
    }

    /**
     * <p>
     * Returns the absolute value of this {@link BigFraction}.
     * </p>
     *
     * @return the absolute value as a {@link BigFraction}.
     */
    public BigFraction abs() {
        return (numerator.signum() == 1) ? this : negate();
    }

    /**
     * <p>
     * Adds the value of this fraction to the passed {@link BigInteger},
     * returning the result in reduced form.
     * </p>
     *
     * @param bg
     *            the {@link BigInteger} to add, must'nt be <code>null.
     * @return a <code>BigFraction instance with the resulting values.
     * @throws NullArgumentException
     *             if the {@link BigInteger} is <code>null.
     */
    public BigFraction add(final BigInteger bg) throws NullArgumentException {
        MathUtils.checkNotNull(bg);

        if (numerator.signum() == 0) {
            return new BigFraction(bg);
        }
        if (bg.signum() == 0) {
            return this;
        }

        return new BigFraction(numerator.add(denominator.multiply(bg)), denominator);
    }

    /**
     * <p>
     * Adds the value of this fraction to the passed {@code integer}, returning
     * the result in reduced form.
     * </p>
     *
     * @param i
     *            the {@code integer} to add.
     * @return a <code>BigFraction instance with the resulting values.
     */
    public BigFraction add(final int i) {
        return add(BigInteger.valueOf(i));
    }

    /**
     * <p>
     * Adds the value of this fraction to the passed {@code long}, returning
     * the result in reduced form.
     * </p>
     *
     * @param l
     *            the {@code long} to add.
     * @return a <code>BigFraction instance with the resulting values.
     */
    public BigFraction add(final long l) {
        return add(BigInteger.valueOf(l));
    }

    /**
     * <p>
     * Adds the value of this fraction to another, returning the result in
     * reduced form.
     * </p>
     *
     * @param fraction
     *            the {@link BigFraction} to add, must not be <code>null.
     * @return a {@link BigFraction} instance with the resulting values.
     * @throws NullArgumentException if the {@link BigFraction} is {@code null}.
     */
    public BigFraction add(final BigFraction fraction) {
        if (fraction == null) {
            throw new NullArgumentException(LocalizedFormats.FRACTION);
        }
        if (fraction.numerator.signum() == 0) {
            return this;
        }
        if (numerator.signum() == 0) {
            return fraction;
        }

        BigInteger num = null;
        BigInteger den = null;

        if (denominator.equals(fraction.denominator)) {
            num = numerator.add(fraction.numerator);
            den = denominator;
        } else {
            num = (numerator.multiply(fraction.denominator)).add((fraction.numerator).multiply(denominator));
            den = denominator.multiply(fraction.denominator);
        }

        if (num.signum() == 0) {
            return ZERO;
        }

        return new BigFraction(num, den);

    }

    /**
     * <p>
     * Gets the fraction as a <code>BigDecimal. This calculates the
     * fraction as the numerator divided by denominator.
     * </p>
     *
     * @return the fraction as a <code>BigDecimal.
     * @throws ArithmeticException
     *             if the exact quotient does not have a terminating decimal
     *             expansion.
     * @see BigDecimal
     */
    public BigDecimal bigDecimalValue() {
        return new BigDecimal(numerator).divide(new BigDecimal(denominator));
    }

    /**
     * <p>
     * Gets the fraction as a <code>BigDecimal following the passed
     * rounding mode. This calculates the fraction as the numerator divided by
     * denominator.
     * </p>
     *
     * @param roundingMode
     *            rounding mode to apply. see {@link BigDecimal} constants.
     * @return the fraction as a <code>BigDecimal.
     * @throws IllegalArgumentException
     *             if {@code roundingMode} does not represent a valid rounding
     *             mode.
     * @see BigDecimal
     */
    public BigDecimal bigDecimalValue(final int roundingMode) {
        return new BigDecimal(numerator).divide(new BigDecimal(denominator), roundingMode);
    }

    /**
     * <p>
     * Gets the fraction as a <code>BigDecimal following the passed scale
     * and rounding mode. This calculates the fraction as the numerator divided
     * by denominator.
     * </p>
     *
     * @param scale
     *            scale of the <code>BigDecimal quotient to be returned.
     *            see {@link BigDecimal} for more information.
     * @param roundingMode
     *            rounding mode to apply. see {@link BigDecimal} constants.
     * @return the fraction as a <code>BigDecimal.
     * @see BigDecimal
     */
    public BigDecimal bigDecimalValue(final int scale, final int roundingMode) {
        return new BigDecimal(numerator).divide(new BigDecimal(denominator), scale, roundingMode);
    }

    /**
     * <p>
     * Compares this object to another based on size.
     * </p>
     *
     * @param object
     *            the object to compare to, must not be <code>null.
     * @return -1 if this is less than {@code object}, +1 if this is greater
     *         than {@code object}, 0 if they are equal.
     * @see java.lang.Comparable#compareTo(java.lang.Object)
     */
    public int compareTo(final BigFraction object) {
        int lhsSigNum = numerator.signum();
        int rhsSigNum = object.numerator.signum();

        if (lhsSigNum != rhsSigNum) {
            return (lhsSigNum > rhsSigNum) ? 1 : -1;
        }
        if (lhsSigNum == 0) {
            return 0;
        }

        BigInteger nOd = numerator.multiply(object.denominator);
        BigInteger dOn = denominator.multiply(object.numerator);
        return nOd.compareTo(dOn);
    }

    /**
     * <p>
     * Divide the value of this fraction by the passed {@code BigInteger},
     * ie {@code this * 1 / bg}, returning the result in reduced form.
     * </p>
     *
     * @param bg the {@code BigInteger} to divide by, must not be {@code null}
     * @return a {@link BigFraction} instance with the resulting values
     * @throws NullArgumentException if the {@code BigInteger} is {@code null}
     * @throws MathArithmeticException if the fraction to divide by is zero
     */
    public BigFraction divide(final BigInteger bg) {
        if (bg == null) {
            throw new NullArgumentException(LocalizedFormats.FRACTION);
        }
        if (bg.signum() == 0) {
            throw new MathArithmeticException(LocalizedFormats.ZERO_DENOMINATOR);
        }
        if (numerator.signum() == 0) {
            return ZERO;
        }
        return new BigFraction(numerator, denominator.multiply(bg));
    }

    /**
     * <p>
     * Divide the value of this fraction by the passed {@code int}, ie
     * {@code this * 1 / i}, returning the result in reduced form.
     * </p>
     *
     * @param i the {@code int} to divide by
     * @return a {@link BigFraction} instance with the resulting values
     * @throws MathArithmeticException if the fraction to divide by is zero
     */
    public BigFraction divide(final int i) {
        return divide(BigInteger.valueOf(i));
    }

    /**
     * <p>
     * Divide the value of this fraction by the passed {@code long}, ie
     * {@code this * 1 / l}, returning the result in reduced form.
     * </p>
     *
     * @param l the {@code long} to divide by
     * @return a {@link BigFraction} instance with the resulting values
     * @throws MathArithmeticException if the fraction to divide by is zero
     */
    public BigFraction divide(final long l) {
        return divide(BigInteger.valueOf(l));
    }

    /**
     * <p>
     * Divide the value of this fraction by another, returning the result in
     * reduced form.
     * </p>
     *
     * @param fraction Fraction to divide by, must not be {@code null}.
     * @return a {@link BigFraction} instance with the resulting values.
     * @throws NullArgumentException if the {@code fraction} is {@code null}.
     * @throws MathArithmeticException if the fraction to divide by is zero
     */
    public BigFraction divide(final BigFraction fraction) {
        if (fraction == null) {
            throw new NullArgumentException(LocalizedFormats.FRACTION);
        }
        if (fraction.numerator.signum() == 0) {
            throw new MathArithmeticException(LocalizedFormats.ZERO_DENOMINATOR);
        }
        if (numerator.signum() == 0) {
            return ZERO;
        }

        return multiply(fraction.reciprocal());
    }

    /**
     * <p>
     * Gets the fraction as a {@code double}. This calculates the fraction as
     * the numerator divided by denominator.
     * </p>
     *
     * @return the fraction as a {@code double}
     * @see java.lang.Number#doubleValue()
     */
    @Override
    public double doubleValue() {
        double result = numerator.doubleValue() / denominator.doubleValue();
        if (Double.isNaN(result)) {
            // Numerator and/or denominator must be out of range:
            // Calculate how far to shift them to put them in range.
            int shift = FastMath.max(numerator.bitLength(),
                                     denominator.bitLength()) - FastMath.getExponent(Double.MAX_VALUE);
            result = numerator.shiftRight(shift).doubleValue() /
                denominator.shiftRight(shift).doubleValue();
        }
        return result;
    }

    /**
     * <p>
     * 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.
     * </p>
     *
     * @param other
     *            fraction to test for equality to this fraction, can be
     *            <code>null.
     * @return true if two fractions are equal, false if object is
     *         <code>null, not an instance of {@link BigFraction}, or not
     *         equal to this fraction instance.
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(final Object other) {
        boolean ret = false;

        if (this == other) {
            ret = true;
        } else if (other instanceof BigFraction) {
            BigFraction rhs = ((BigFraction) other).reduce();
            BigFraction thisOne = this.reduce();
            ret = thisOne.numerator.equals(rhs.numerator) && thisOne.denominator.equals(rhs.denominator);
        }

        return ret;
    }

    /**
     * <p>
     * Gets the fraction as a {@code float}. This calculates the fraction as
     * the numerator divided by denominator.
     * </p>
     *
     * @return the fraction as a {@code float}.
     * @see java.lang.Number#floatValue()
     */
    @Override
    public float floatValue() {
        float result = numerator.floatValue() / denominator.floatValue();
        if (Double.isNaN(result)) {
            // Numerator and/or denominator must be out of range:
            // Calculate how far to shift them to put them in range.
            int shift = FastMath.max(numerator.bitLength(),
                                     denominator.bitLength()) - FastMath.getExponent(Float.MAX_VALUE);
            result = numerator.shiftRight(shift).floatValue() /
                denominator.shiftRight(shift).floatValue();
        }
        return result;
    }

    /**
     * <p>
     * Access the denominator as a <code>BigInteger.
     * </p>
     *
     * @return the denominator as a <code>BigInteger.
     */
    public BigInteger getDenominator() {
        return denominator;
    }

    /**
     * <p>
     * Access the denominator as a {@code int}.
     * </p>
     *
     * @return the denominator as a {@code int}.
     */
    public int getDenominatorAsInt() {
        return denominator.intValue();
    }

    /**
     * <p>
     * Access the denominator as a {@code long}.
     * </p>
     *
     * @return the denominator as a {@code long}.
     */
    public long getDenominatorAsLong() {
        return denominator.longValue();
    }

    /**
     * <p>
     * Access the numerator as a <code>BigInteger.
     * </p>
     *
     * @return the numerator as a <code>BigInteger.
     */
    public BigInteger getNumerator() {
        return numerator;
    }

    /**
     * <p>
     * Access the numerator as a {@code int}.
     * </p>
     *
     * @return the numerator as a {@code int}.
     */
    public int getNumeratorAsInt() {
        return numerator.intValue();
    }

    /**
     * <p>
     * Access the numerator as a {@code long}.
     * </p>
     *
     * @return the numerator as a {@code long}.
     */
    public long getNumeratorAsLong() {
        return numerator.longValue();
    }

    /**
     * <p>
     * Gets a hashCode for the fraction.
     * </p>
     *
     * @return a hash code value for this object.
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        return 37 * (37 * 17 + numerator.hashCode()) + denominator.hashCode();
    }

    /**
     * <p>
     * Gets the fraction as an {@code int}. This returns the whole number part
     * of the fraction.
     * </p>
     *
     * @return the whole number fraction part.
     * @see java.lang.Number#intValue()
     */
    @Override
    public int intValue() {
        return numerator.divide(denominator).intValue();
    }

    /**
     * <p>
     * Gets the fraction as a {@code long}. This returns the whole number part
     * of the fraction.
     * </p>
     *
     * @return the whole number fraction part.
     * @see java.lang.Number#longValue()
     */
    @Override
    public long longValue() {
        return numerator.divide(denominator).longValue();
    }

    /**
     * <p>
     * Multiplies the value of this fraction by the passed
     * <code>BigInteger, returning the result in reduced form.
     * </p>
     *
     * @param bg the {@code BigInteger} to multiply by.
     * @return a {@code BigFraction} instance with the resulting values.
     * @throws NullArgumentException if {@code bg} is {@code null}.
     */
    public BigFraction multiply(final BigInteger bg) {
        if (bg == null) {
            throw new NullArgumentException();
        }
        if (numerator.signum() == 0 || bg.signum() == 0) {
            return ZERO;
        }
        return new BigFraction(bg.multiply(numerator), denominator);
    }

    /**
     * <p>
     * Multiply the value of this fraction by the passed {@code int}, returning
     * the result in reduced form.
     * </p>
     *
     * @param i
     *            the {@code int} to multiply by.
     * @return a {@link BigFraction} instance with the resulting values.
     */
    public BigFraction multiply(final int i) {
        if (i == 0 || numerator.signum() == 0) {
            return ZERO;
        }

        return multiply(BigInteger.valueOf(i));
    }

    /**
     * <p>
     * Multiply the value of this fraction by the passed {@code long},
     * returning the result in reduced form.
     * </p>
     *
     * @param l
     *            the {@code long} to multiply by.
     * @return a {@link BigFraction} instance with the resulting values.
     */
    public BigFraction multiply(final long l) {
        if (l == 0 || numerator.signum() == 0) {
            return ZERO;
        }

        return multiply(BigInteger.valueOf(l));
    }

    /**
     * <p>
     * Multiplies the value of this fraction by another, returning the result in
     * reduced form.
     * </p>
     *
     * @param fraction Fraction to multiply by, must not be {@code null}.
     * @return a {@link BigFraction} instance with the resulting values.
     * @throws NullArgumentException if {@code fraction} is {@code null}.
     */
    public BigFraction multiply(final BigFraction fraction) {
        if (fraction == null) {
            throw new NullArgumentException(LocalizedFormats.FRACTION);
        }
        if (numerator.signum() == 0 ||
            fraction.numerator.signum() == 0) {
            return ZERO;
        }
        return new BigFraction(numerator.multiply(fraction.numerator),
                               denominator.multiply(fraction.denominator));
    }

    /**
     * <p>
     * Return the additive inverse of this fraction, returning the result in
     * reduced form.
     * </p>
     *
     * @return the negation of this fraction.
     */
    public BigFraction negate() {
        return new BigFraction(numerator.negate(), denominator);
    }

    /**
     * <p>
     * Gets the fraction percentage as a {@code double}. This calculates the
     * fraction as the numerator divided by denominator multiplied by 100.
     * </p>
     *
     * @return the fraction percentage as a {@code double}.
     */
    public double percentageValue() {
        return multiply(ONE_HUNDRED).doubleValue();
    }

    /**
     * <p>
     * Returns a {@code BigFraction} whose value is
     * {@code (this<sup>exponent)}, returning the result in reduced form.
     * </p>
     *
     * @param exponent
     *            exponent to which this {@code BigFraction} is to be
     *            raised.
     * @return <tt>thisexponent.
     */
    public BigFraction pow(final int exponent) {
        if (exponent == 0) {
            return ONE;
        }
        if (numerator.signum() == 0) {
            return this;
        }

        if (exponent < 0) {
            return new BigFraction(denominator.pow(-exponent), numerator.pow(-exponent));
        }
        return new BigFraction(numerator.pow(exponent), denominator.pow(exponent));
    }

    /**
     * <p>
     * Returns a <code>BigFraction whose value is
     * <tt>(thisexponent), returning the result in reduced form.
     * </p>
     *
     * @param exponent
     *            exponent to which this <code>BigFraction is to be raised.
     * @return <tt>thisexponent as a BigFraction.
     */
    public BigFraction pow(final long exponent) {
        if (exponent == 0) {
            return ONE;
        }
        if (numerator.signum() == 0) {
            return this;
        }

        if (exponent < 0) {
            return new BigFraction(ArithmeticUtils.pow(denominator, -exponent),
                                   ArithmeticUtils.pow(numerator,   -exponent));
        }
        return new BigFraction(ArithmeticUtils.pow(numerator,   exponent),
                               ArithmeticUtils.pow(denominator, exponent));
    }

    /**
     * <p>
     * Returns a <code>BigFraction whose value is
     * <tt>(thisexponent), returning the result in reduced form.
     * </p>
     *
     * @param exponent
     *            exponent to which this <code>BigFraction is to be raised.
     * @return <tt>thisexponent as a BigFraction.
     */
    public BigFraction pow(final BigInteger exponent) {
        if (exponent.signum() == 0) {
            return ONE;
        }
        if (numerator.signum() == 0) {
            return this;
        }

        if (exponent.signum() == -1) {
            final BigInteger eNeg = exponent.negate();
            return new BigFraction(ArithmeticUtils.pow(denominator, eNeg),
                                   ArithmeticUtils.pow(numerator,   eNeg));
        }
        return new BigFraction(ArithmeticUtils.pow(numerator,   exponent),
                               ArithmeticUtils.pow(denominator, exponent));
    }

    /**
     * <p>
     * Returns a <code>double whose value is
     * <tt>(thisexponent), returning the result in reduced form.
     * </p>
     *
     * @param exponent
     *            exponent to which this <code>BigFraction is to be raised.
     * @return <tt>thisexponent.
     */
    public double pow(final double exponent) {
        return FastMath.pow(numerator.doubleValue(),   exponent) /
               FastMath.pow(denominator.doubleValue(), exponent);
    }

    /**
     * <p>
     * Return the multiplicative inverse of this fraction.
     * </p>
     *
     * @return the reciprocal fraction.
     */
    public BigFraction reciprocal() {
        return new BigFraction(denominator, numerator);
    }

    /**
     * <p>
     * Reduce this <code>BigFraction to its lowest terms.
     * </p>
     *
     * @return the reduced <code>BigFraction. It doesn't change anything if
     *         the fraction can be reduced.
     */
    public BigFraction reduce() {
        final BigInteger gcd = numerator.gcd(denominator);

        if (BigInteger.ONE.compareTo(gcd) < 0) {
            return new BigFraction(numerator.divide(gcd), denominator.divide(gcd));
        } else {
            return this;
        }
    }

    /**
     * <p>
     * Subtracts the value of an {@link BigInteger} from the value of this
     * {@code BigFraction}, returning the result in reduced form.
     * </p>
     *
     * @param bg the {@link BigInteger} to subtract, cannot be {@code null}.
     * @return a {@code BigFraction} instance with the resulting values.
     * @throws NullArgumentException if the {@link BigInteger} is {@code null}.
     */
    public BigFraction subtract(final BigInteger bg) {
        if (bg == null) {
            throw new NullArgumentException();
        }
        if (bg.signum() == 0) {
            return this;
        }
        if (numerator.signum() == 0) {
            return new BigFraction(bg.negate());
        }

        return new BigFraction(numerator.subtract(denominator.multiply(bg)), denominator);
    }

    /**
     * <p>
     * Subtracts the value of an {@code integer} from the value of this
     * {@code BigFraction}, returning the result in reduced form.
     * </p>
     *
     * @param i the {@code integer} to subtract.
     * @return a {@code BigFraction} instance with the resulting values.
     */
    public BigFraction subtract(final int i) {
        return subtract(BigInteger.valueOf(i));
    }

    /**
     * <p>
     * Subtracts the value of a {@code long} from the value of this
     * {@code BigFraction}, returning the result in reduced form.
     * </p>
     *
     * @param l the {@code long} to subtract.
     * @return a {@code BigFraction} instance with the resulting values.
     */
    public BigFraction subtract(final long l) {
        return subtract(BigInteger.valueOf(l));
    }

    /**
     * <p>
     * Subtracts the value of another fraction from the value of this one,
     * returning the result in reduced form.
     * </p>
     *
     * @param fraction {@link BigFraction} to subtract, must not be {@code null}.
     * @return a {@link BigFraction} instance with the resulting values
     * @throws NullArgumentException if the {@code fraction} is {@code null}.
     */
    public BigFraction subtract(final BigFraction fraction) {
        if (fraction == null) {
            throw new NullArgumentException(LocalizedFormats.FRACTION);
        }
        if (fraction.numerator.signum() == 0) {
            return this;
        }
        if (numerator.signum() == 0) {
            return fraction.negate();
        }

        BigInteger num = null;
        BigInteger den = null;
        if (denominator.equals(fraction.denominator)) {
            num = numerator.subtract(fraction.numerator);
            den = denominator;
        } else {
            num = (numerator.multiply(fraction.denominator)).subtract((fraction.numerator).multiply(denominator));
            den = denominator.multiply(fraction.denominator);
        }
        return new BigFraction(num, den);

    }

    /**
     * <p>
     * Returns the <code>String representing this fraction, ie
     * "num / dem" or just "num" if the denominator is one.
     * </p>
     *
     * @return a string representation of the fraction.
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        String str = null;
        if (BigInteger.ONE.equals(denominator)) {
            str = numerator.toString();
        } else if (BigInteger.ZERO.equals(numerator)) {
            str = "0";
        } else {
            str = numerator + " / " + denominator;
        }
        return str;
    }

    /** {@inheritDoc} */
    public BigFractionField getField() {
        return BigFractionField.getInstance();
    }

}


my book on functional programming

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.