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Java example source code file (BigRealTest.java)

This example Java source code file (BigRealTest.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

assert, bigdecimal, biginteger, bigreal, bigrealtest, math, reals, test

The BigRealTest.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.util;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.MathContext;

import org.apache.commons.math3.TestUtils;
import org.apache.commons.math3.exception.MathArithmeticException;
import org.junit.Assert;
import org.junit.Test;

public class BigRealTest {

    @Test
    public void testConstructor() {
        Assert.assertEquals(1.625,
                            new BigReal(new BigDecimal("1.625")).doubleValue(),
                            1.0e-15);
        Assert.assertEquals(-5.0,
                            new BigReal(new BigInteger("-5")).doubleValue(),
                            1.0e-15);
        Assert.assertEquals(-5.0, new BigReal(new BigInteger("-5"),
                                              MathContext.DECIMAL64)
            .doubleValue(), 1.0e-15);
        Assert
            .assertEquals(0.125,
                          new BigReal(new BigInteger("125"), 3).doubleValue(),
                          1.0e-15);
        Assert.assertEquals(0.125, new BigReal(new BigInteger("125"), 3,
                                               MathContext.DECIMAL64)
            .doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal(new char[] {
            '1', '.', '6', '2', '5'
        }).doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal(new char[] {
            'A', 'A', '1', '.', '6', '2', '5', '9'
        }, 2, 5).doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal(new char[] {
            'A', 'A', '1', '.', '6', '2', '5', '9'
        }, 2, 5, MathContext.DECIMAL64).doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal(new char[] {
            '1', '.', '6', '2', '5'
        }, MathContext.DECIMAL64).doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal(1.625).doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal(1.625, MathContext.DECIMAL64)
            .doubleValue(), 1.0e-15);
        Assert.assertEquals(-5.0, new BigReal(-5).doubleValue(), 1.0e-15);
        Assert.assertEquals(-5.0, new BigReal(-5, MathContext.DECIMAL64)
            .doubleValue(), 1.0e-15);
        Assert.assertEquals(-5.0, new BigReal(-5l).doubleValue(), 1.0e-15);
        Assert.assertEquals(-5.0, new BigReal(-5l, MathContext.DECIMAL64)
            .doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal("1.625").doubleValue(), 1.0e-15);
        Assert.assertEquals(1.625, new BigReal("1.625", MathContext.DECIMAL64)
            .doubleValue(), 1.0e-15);
    }

    @Test
    public void testCompareTo() {
        BigReal first = new BigReal(1.0 / 2.0);
        BigReal second = new BigReal(1.0 / 3.0);
        BigReal third = new BigReal(1.0 / 2.0);

        Assert.assertEquals(0, first.compareTo(first));
        Assert.assertEquals(0, first.compareTo(third));
        Assert.assertEquals(1, first.compareTo(second));
        Assert.assertEquals(-1, second.compareTo(first));

    }

    @Test
    public void testAdd() {
        BigReal a = new BigReal("1.2345678");
        BigReal b = new BigReal("8.7654321");
        Assert.assertEquals(9.9999999, a.add(b).doubleValue(), 1.0e-15);
    }

    @Test
    public void testSubtract() {
        BigReal a = new BigReal("1.2345678");
        BigReal b = new BigReal("8.7654321");
        Assert.assertEquals(-7.5308643, a.subtract(b).doubleValue(), 1.0e-15);
    }

    @Test
    public void testNegate() {
        BigReal a = new BigReal("1.2345678");
        BigReal zero = new BigReal("0.0000000");
        Assert.assertEquals(a.negate().add(a), zero);
        Assert.assertEquals(a.add(a.negate()), zero);
        Assert.assertEquals(zero, zero.negate());
    }

    @Test
    public void testDivide() {
        BigReal a = new BigReal("1.0000000000");
        BigReal b = new BigReal("0.0009765625");
        Assert.assertEquals(1024.0, a.divide(b).doubleValue(), 1.0e-15);
    }

    @Test(expected = MathArithmeticException.class)
    public void testDivisionByZero() {
        final BigReal a = BigReal.ONE;
        final BigReal b = BigReal.ZERO;
        a.divide(b);
    }

    @Test
    public void testReciprocal() {
        BigReal a = new BigReal("1.2345678");
        double eps = FastMath.pow(10., -a.getScale());
        BigReal one = new BigReal("1.0000000");
        BigReal b = a.reciprocal();
        BigReal r = one.subtract(a.multiply(b));
        Assert.assertTrue(FastMath.abs(r.doubleValue()) <= eps);
        r = one.subtract(b.multiply(a));
        Assert.assertTrue(FastMath.abs(r.doubleValue()) <= eps);
    }

    @Test(expected = MathArithmeticException.class)
    public void testReciprocalOfZero() {
        BigReal.ZERO.reciprocal();
    }

    @Test
    public void testMultiply() {
        BigReal a = new BigReal("1024.0");
        BigReal b = new BigReal("0.0009765625");
        Assert.assertEquals(1.0, a.multiply(b).doubleValue(), 1.0e-15);
        int n = 1024;
        Assert.assertEquals(1.0, b.multiply(n).doubleValue(), 1.0e-15);
    }

    @Test
    public void testDoubleValue() {
        Assert.assertEquals(0.5, new BigReal(0.5).doubleValue(), 1.0e-15);
    }

    @Test
    public void testBigDecimalValue() {
        BigDecimal pi = new BigDecimal(
                                       "3.1415926535897932384626433832795028841971693993751");
        Assert.assertEquals(pi, new BigReal(pi).bigDecimalValue());
        Assert.assertEquals(new BigDecimal(0.5),
                            new BigReal(1.0 / 2.0).bigDecimalValue());
    }

    @Test
    public void testEqualsAndHashCode() {
        BigReal zero = new BigReal(0.0);
        BigReal nullReal = null;
        Assert.assertTrue(zero.equals(zero));
        Assert.assertFalse(zero.equals(nullReal));
        Assert.assertFalse(zero.equals(Double.valueOf(0)));
        BigReal zero2 = new BigReal(0.0);
        Assert.assertTrue(zero.equals(zero2));
        Assert.assertEquals(zero.hashCode(), zero2.hashCode());
        BigReal one = new BigReal(1.0);
        Assert.assertFalse((one.equals(zero) || zero.equals(one)));
        Assert.assertTrue(one.equals(BigReal.ONE));
    }

    @Test
    public void testSerial() {
        BigReal[] Reals = {
            new BigReal(3.0), BigReal.ONE, BigReal.ZERO, new BigReal(17),
            new BigReal(FastMath.PI), new BigReal(-2.5)
        };
        for (BigReal Real : Reals) {
            Assert.assertEquals(Real, TestUtils.serializeAndRecover(Real));
        }
    }
}

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