428 lines
18 KiB
Java
428 lines
18 KiB
Java
/*
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* Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test
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* @bug 4851776 4907265 6177836 6876282 8066842
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* @summary Some tests for the divide methods.
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* @author Joseph D. Darcy
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*/
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import java.math.*;
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import static java.math.BigDecimal.*;
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public class DivideTests {
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// Preliminary exact divide method; could be used for comparison
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// purposes.
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BigDecimal anotherDivide(BigDecimal dividend, BigDecimal divisor) {
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/*
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* Handle zero cases first.
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*/
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if (divisor.signum() == 0) { // x/0
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if (dividend.signum() == 0) // 0/0
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throw new ArithmeticException("Division undefined"); // NaN
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throw new ArithmeticException("Division by zero");
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}
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if (dividend.signum() == 0) // 0/y
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return BigDecimal.ZERO;
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else {
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/*
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* Determine if there is a result with a terminating
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* decimal expansion. Putting aside overflow and
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* underflow considerations, the existance of an exact
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* result only depends on the ratio of the intVal's of the
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* dividend (i.e. this) and divisor since the scales
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* of the argument just affect where the decimal point
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* lies.
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*
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* For the ratio of (a = this.intVal) and (b =
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* divisor.intVal) to have a finite decimal expansion,
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* once a/b is put in lowest terms, b must be equal to
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* (2^i)*(5^j) for some integer i,j >= 0. Therefore, we
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* first compute to see if b_prime =(b/gcd(a,b)) is equal
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* to (2^i)*(5^j).
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*/
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BigInteger TWO = BigInteger.valueOf(2);
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BigInteger FIVE = BigInteger.valueOf(5);
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BigInteger TEN = BigInteger.valueOf(10);
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BigInteger divisorIntvalue = divisor.scaleByPowerOfTen(divisor.scale()).toBigInteger().abs();
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BigInteger dividendIntvalue = dividend.scaleByPowerOfTen(dividend.scale()).toBigInteger().abs();
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BigInteger b_prime = divisorIntvalue.divide(dividendIntvalue.gcd(divisorIntvalue));
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boolean goodDivisor = false;
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int i=0, j=0;
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badDivisor: {
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while(! b_prime.equals(BigInteger.ONE) ) {
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int b_primeModTen = b_prime.mod(TEN).intValue() ;
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switch(b_primeModTen) {
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case 0:
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// b_prime divisible by 10=2*5, increment i and j
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i++;
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j++;
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b_prime = b_prime.divide(TEN);
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break;
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case 5:
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// b_prime divisible by 5, increment j
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j++;
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b_prime = b_prime.divide(FIVE);
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break;
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case 2:
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case 4:
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case 6:
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case 8:
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// b_prime divisible by 2, increment i
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i++;
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b_prime = b_prime.divide(TWO);
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break;
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default: // hit something we shouldn't have
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b_prime = BigInteger.ONE; // terminate loop
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break badDivisor;
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}
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}
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goodDivisor = true;
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}
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if( ! goodDivisor ) {
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throw new ArithmeticException("Non terminating decimal expansion");
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}
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else {
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// What is a rule for determining how many digits are
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// needed? Once that is determined, cons up a new
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// MathContext object and pass it on to the divide(bd,
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// mc) method; precision == ?, roundingMode is unnecessary.
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// Are we sure this is the right scale to use? Should
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// also determine a precision-based method.
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MathContext mc = new MathContext(dividend.precision() +
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(int)Math.ceil(
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10.0*divisor.precision()/3.0),
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RoundingMode.UNNECESSARY);
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// Should do some more work here to rescale, etc.
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return dividend.divide(divisor, mc);
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}
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}
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}
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public static int powersOf2and5() {
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int failures = 0;
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for(int i = 0; i < 6; i++) {
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int powerOf2 = (int)StrictMath.pow(2.0, i);
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for(int j = 0; j < 6; j++) {
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int powerOf5 = (int)StrictMath.pow(5.0, j);
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int product;
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BigDecimal bd;
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try {
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bd = BigDecimal.ONE.divide(new BigDecimal(product=powerOf2*powerOf5));
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} catch (ArithmeticException e) {
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failures++;
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System.err.println((new BigDecimal(powerOf2)).toString() + " / " +
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(new BigDecimal(powerOf5)).toString() + " threw an exception.");
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e.printStackTrace();
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}
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try {
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bd = new BigDecimal(powerOf2).divide(new BigDecimal(powerOf5));
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} catch (ArithmeticException e) {
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failures++;
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System.err.println((new BigDecimal(powerOf2)).toString() + " / " +
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(new BigDecimal(powerOf5)).toString() + " threw an exception.");
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e.printStackTrace();
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}
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try {
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bd = new BigDecimal(powerOf5).divide(new BigDecimal(powerOf2));
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} catch (ArithmeticException e) {
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failures++;
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System.err.println((new BigDecimal(powerOf5)).toString() + " / " +
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(new BigDecimal(powerOf2)).toString() + " threw an exception.");
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e.printStackTrace();
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}
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}
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}
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return failures;
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}
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public static int nonTerminating() {
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int failures = 0;
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int[] primes = {1, 3, 7, 13, 17};
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// For each pair of prime products, verify the ratio of
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// non-equal products has a non-terminating expansion.
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for(int i = 0; i < primes.length; i++) {
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for(int j = i+1; j < primes.length; j++) {
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for(int m = 0; m < primes.length; m++) {
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for(int n = m+1; n < primes.length; n++) {
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int dividend = primes[i] * primes[j];
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int divisor = primes[m] * primes[n];
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if ( ((dividend/divisor) * divisor) != dividend ) {
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try {
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BigDecimal quotient = (new BigDecimal(dividend).
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divide(new BigDecimal(divisor)));
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failures++;
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System.err.println("Exact quotient " + quotient.toString() +
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" returned for non-terminating fraction " +
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dividend + " / " + divisor + ".");
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}
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catch (ArithmeticException e) {
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; // Correct result
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}
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}
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}
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}
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}
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}
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return failures;
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}
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public static int properScaleTests(){
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int failures = 0;
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BigDecimal[][] testCases = {
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{new BigDecimal("1"), new BigDecimal("5"), new BigDecimal("2e-1")},
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{new BigDecimal("1"), new BigDecimal("50e-1"), new BigDecimal("2e-1")},
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{new BigDecimal("10e-1"), new BigDecimal("5"), new BigDecimal("2e-1")},
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{new BigDecimal("1"), new BigDecimal("500e-2"), new BigDecimal("2e-1")},
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{new BigDecimal("100e-2"), new BigDecimal("5"), new BigDecimal("20e-2")},
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{new BigDecimal("1"), new BigDecimal("32"), new BigDecimal("3125e-5")},
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{new BigDecimal("1"), new BigDecimal("64"), new BigDecimal("15625e-6")},
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{new BigDecimal("1.0000000"), new BigDecimal("64"), new BigDecimal("156250e-7")},
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};
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for(BigDecimal[] tc : testCases) {
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BigDecimal quotient;
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if (! (quotient = tc[0].divide(tc[1])).equals(tc[2]) ) {
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failures++;
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System.err.println("Unexpected quotient from " + tc[0] + " / " + tc[1] +
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"; expected " + tc[2] + " got " + quotient);
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}
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}
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return failures;
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}
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public static int trailingZeroTests() {
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int failures = 0;
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MathContext mc = new MathContext(3, RoundingMode.FLOOR);
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BigDecimal[][] testCases = {
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{new BigDecimal("19"), new BigDecimal("100"), new BigDecimal("0.19")},
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{new BigDecimal("21"), new BigDecimal("110"), new BigDecimal("0.190")},
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};
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for(BigDecimal[] tc : testCases) {
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BigDecimal quotient;
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if (! (quotient = tc[0].divide(tc[1], mc)).equals(tc[2]) ) {
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failures++;
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System.err.println("Unexpected quotient from " + tc[0] + " / " + tc[1] +
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"; expected " + tc[2] + " got " + quotient);
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}
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}
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return failures;
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}
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public static int scaledRoundedDivideTests() {
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int failures = 0;
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// Tests of the traditional scaled divide under different
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// rounding modes.
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// Encode rounding mode and scale for the divide in a
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// BigDecimal with the significand equal to the rounding mode
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// and the scale equal to the number's scale.
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// {dividend, dividisor, rounding, quotient}
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BigDecimal a = new BigDecimal("31415");
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BigDecimal a_minus = a.negate();
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BigDecimal b = new BigDecimal("10000");
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BigDecimal c = new BigDecimal("31425");
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BigDecimal c_minus = c.negate();
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// Ad hoc tests
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BigDecimal d = new BigDecimal(new BigInteger("-37361671119238118911893939591735"), 10);
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BigDecimal e = new BigDecimal(new BigInteger("74723342238476237823787879183470"), 15);
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BigDecimal[][] testCases = {
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{a, b, BigDecimal.valueOf(ROUND_UP, 3), new BigDecimal("3.142")},
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{a_minus, b, BigDecimal.valueOf(ROUND_UP, 3), new BigDecimal("-3.142")},
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{a, b, BigDecimal.valueOf(ROUND_DOWN, 3), new BigDecimal("3.141")},
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{a_minus, b, BigDecimal.valueOf(ROUND_DOWN, 3), new BigDecimal("-3.141")},
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{a, b, BigDecimal.valueOf(ROUND_CEILING, 3), new BigDecimal("3.142")},
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{a_minus, b, BigDecimal.valueOf(ROUND_CEILING, 3), new BigDecimal("-3.141")},
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{a, b, BigDecimal.valueOf(ROUND_FLOOR, 3), new BigDecimal("3.141")},
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{a_minus, b, BigDecimal.valueOf(ROUND_FLOOR, 3), new BigDecimal("-3.142")},
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{a, b, BigDecimal.valueOf(ROUND_HALF_UP, 3), new BigDecimal("3.142")},
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{a_minus, b, BigDecimal.valueOf(ROUND_HALF_UP, 3), new BigDecimal("-3.142")},
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{a, b, BigDecimal.valueOf(ROUND_DOWN, 3), new BigDecimal("3.141")},
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{a_minus, b, BigDecimal.valueOf(ROUND_DOWN, 3), new BigDecimal("-3.141")},
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{a, b, BigDecimal.valueOf(ROUND_HALF_EVEN, 3), new BigDecimal("3.142")},
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{a_minus, b, BigDecimal.valueOf(ROUND_HALF_EVEN, 3), new BigDecimal("-3.142")},
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{c, b, BigDecimal.valueOf(ROUND_HALF_EVEN, 3), new BigDecimal("3.142")},
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{c_minus, b, BigDecimal.valueOf(ROUND_HALF_EVEN, 3), new BigDecimal("-3.142")},
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{d, e, BigDecimal.valueOf(ROUND_HALF_UP, -5), BigDecimal.valueOf(-1, -5)},
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{d, e, BigDecimal.valueOf(ROUND_HALF_DOWN, -5), BigDecimal.valueOf(0, -5)},
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{d, e, BigDecimal.valueOf(ROUND_HALF_EVEN, -5), BigDecimal.valueOf(0, -5)},
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};
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for(BigDecimal tc[] : testCases) {
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int scale = tc[2].scale();
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int rm = tc[2].unscaledValue().intValue();
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BigDecimal quotient = tc[0].divide(tc[1], scale, rm);
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if (!quotient.equals(tc[3])) {
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failures++;
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System.err.println("Unexpected quotient from " + tc[0] + " / " + tc[1] +
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" scale " + scale + " rounding mode " + RoundingMode.valueOf(rm) +
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"; expected " + tc[3] + " got " + quotient);
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}
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}
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// 6876282
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BigDecimal[][] testCases2 = {
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// { dividend, divisor, expected quotient }
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{ new BigDecimal(3090), new BigDecimal(7), new BigDecimal(441) },
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{ new BigDecimal("309000000000000000000000"), new BigDecimal("700000000000000000000"),
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new BigDecimal(441) },
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{ new BigDecimal("962.430000000000"), new BigDecimal("8346463.460000000000"),
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new BigDecimal("0.000115309916") },
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{ new BigDecimal("18446744073709551631"), new BigDecimal("4611686018427387909"),
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new BigDecimal(4) },
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{ new BigDecimal("18446744073709551630"), new BigDecimal("4611686018427387909"),
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new BigDecimal(4) },
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{ new BigDecimal("23058430092136939523"), new BigDecimal("4611686018427387905"),
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new BigDecimal(5) },
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{ new BigDecimal("-18446744073709551661"), new BigDecimal("-4611686018427387919"),
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new BigDecimal(4) },
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{ new BigDecimal("-18446744073709551660"), new BigDecimal("-4611686018427387919"),
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new BigDecimal(4) },
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};
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for (BigDecimal test[] : testCases2) {
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BigDecimal quo = test[0].divide(test[1], RoundingMode.HALF_UP);
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if (!quo.equals(test[2])) {
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failures++;
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System.err.println("Unexpected quotient from " + test[0] + " / " + test[1] +
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" rounding mode HALF_UP" +
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"; expected " + test[2] + " got " + quo);
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}
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}
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return failures;
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}
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private static int divideByOneTests() {
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int failures = 0;
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//problematic divisor: one with scale 17
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BigDecimal one = BigDecimal.ONE.setScale(17);
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RoundingMode rounding = RoundingMode.UNNECESSARY;
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long[][] unscaledAndScale = new long[][] {
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{ Long.MAX_VALUE, 17},
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{-Long.MAX_VALUE, 17},
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{ Long.MAX_VALUE, 0},
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{-Long.MAX_VALUE, 0},
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{ Long.MAX_VALUE, 100},
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{-Long.MAX_VALUE, 100}
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};
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for (long[] uas : unscaledAndScale) {
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long unscaled = uas[0];
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int scale = (int)uas[1];
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BigDecimal noRound = null;
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try {
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noRound = BigDecimal.valueOf(unscaled, scale).
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divide(one, RoundingMode.UNNECESSARY);
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} catch (ArithmeticException e) {
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failures++;
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System.err.println("ArithmeticException for value " + unscaled
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+ " and scale " + scale + " without rounding");
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}
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BigDecimal roundDown = null;
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try {
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roundDown = BigDecimal.valueOf(unscaled, scale).
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divide(one, RoundingMode.DOWN);
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} catch (ArithmeticException e) {
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failures++;
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System.err.println("ArithmeticException for value " + unscaled
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+ " and scale " + scale + " with rounding down");
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}
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if (noRound != null && roundDown != null
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&& noRound.compareTo(roundDown) != 0) {
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failures++;
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System.err.println("Equality failure for value " + unscaled
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+ " and scale " + scale);
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}
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}
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return failures;
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}
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public static void main(String argv[]) {
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int failures = 0;
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failures += powersOf2and5();
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failures += nonTerminating();
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failures += properScaleTests();
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failures += trailingZeroTests();
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failures += scaledRoundedDivideTests();
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failures += divideByOneTests();
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if (failures > 0) {
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throw new RuntimeException("Incurred " + failures +
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" failures while testing division.");
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}
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}
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}
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