| /* |
| * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test |
| * @library /test/lib |
| * @build jdk.test.lib.RandomFactory |
| * @run main HypotTests |
| * @bug 4851638 4939441 8078672 |
| * @summary Tests for {Math, StrictMath}.hypot (use -Dseed=X to set PRNG seed) |
| * @author Joseph D. Darcy |
| * @key randomness |
| */ |
| |
| import jdk.test.lib.RandomFactory; |
| |
| public class HypotTests { |
| private HypotTests(){} |
| |
| static final double infinityD = Double.POSITIVE_INFINITY; |
| static final double NaNd = Double.NaN; |
| |
| /** |
| * Given integers m and n, assuming m < n, the triple (n^2 - m^2, |
| * 2mn, and n^2 + m^2) is a Pythagorean triple with a^2 + b^2 = |
| * c^2. This methods returns a long array holding the Pythagorean |
| * triple corresponding to the inputs. |
| */ |
| static long [] pythagoreanTriple(int m, int n) { |
| long M = m; |
| long N = n; |
| long result[] = new long[3]; |
| |
| |
| result[0] = Math.abs(M*M - N*N); |
| result[1] = Math.abs(2*M*N); |
| result[2] = Math.abs(M*M + N*N); |
| |
| return result; |
| } |
| |
| static int testHypot() { |
| int failures = 0; |
| |
| double [][] testCases = { |
| // Special cases |
| {infinityD, infinityD, infinityD}, |
| {infinityD, 0.0, infinityD}, |
| {infinityD, 1.0, infinityD}, |
| {infinityD, NaNd, infinityD}, |
| {NaNd, NaNd, NaNd}, |
| {0.0, NaNd, NaNd}, |
| {1.0, NaNd, NaNd}, |
| {Double.longBitsToDouble(0x7FF0000000000001L), 1.0, NaNd}, |
| {Double.longBitsToDouble(0xFFF0000000000001L), 1.0, NaNd}, |
| {Double.longBitsToDouble(0x7FF8555555555555L), 1.0, NaNd}, |
| {Double.longBitsToDouble(0xFFF8555555555555L), 1.0, NaNd}, |
| {Double.longBitsToDouble(0x7FFFFFFFFFFFFFFFL), 1.0, NaNd}, |
| {Double.longBitsToDouble(0xFFFFFFFFFFFFFFFFL), 1.0, NaNd}, |
| {Double.longBitsToDouble(0x7FFDeadBeef00000L), 1.0, NaNd}, |
| {Double.longBitsToDouble(0xFFFDeadBeef00000L), 1.0, NaNd}, |
| {Double.longBitsToDouble(0x7FFCafeBabe00000L), 1.0, NaNd}, |
| {Double.longBitsToDouble(0xFFFCafeBabe00000L), 1.0, NaNd}, |
| }; |
| |
| for(int i = 0; i < testCases.length; i++) { |
| failures += testHypotCase(testCases[i][0], testCases[i][1], |
| testCases[i][2]); |
| } |
| |
| // Verify hypot(x, 0.0) is close to x over the entire exponent |
| // range. |
| for(int i = DoubleConsts.MIN_SUB_EXPONENT; |
| i <= Double.MAX_EXPONENT; |
| i++) { |
| double input = Math.scalb(2, i); |
| failures += testHypotCase(input, 0.0, input); |
| } |
| |
| |
| // Test Pythagorean triples |
| |
| // Small ones |
| for(int m = 1; m < 10; m++) { |
| for(int n = m+1; n < 11; n++) { |
| long [] result = pythagoreanTriple(m, n); |
| failures += testHypotCase(result[0], result[1], result[2]); |
| } |
| } |
| |
| // Big ones |
| for(int m = 100000; m < 100100; m++) { |
| for(int n = m+100000; n < 200200; n++) { |
| long [] result = pythagoreanTriple(m, n); |
| failures += testHypotCase(result[0], result[1], result[2]); |
| } |
| } |
| |
| // Approaching overflow tests |
| |
| /* |
| * Create a random value r with an large-ish exponent. The |
| * result of hypot(3*r, 4*r) should be approximately 5*r. (The |
| * computation of 4*r is exact since it just changes the |
| * exponent). While the exponent of r is less than or equal |
| * to (MAX_EXPONENT - 3), the computation should not overflow. |
| */ |
| java.util.Random rand = RandomFactory.getRandom(); |
| for(int i = 0; i < 1000; i++) { |
| double d = rand.nextDouble(); |
| // Scale d to have an exponent equal to MAX_EXPONENT -15 |
| d = Math.scalb(d, Double.MAX_EXPONENT |
| -15 - Tests.ilogb(d)); |
| for(int j = 0; j <= 13; j += 1) { |
| failures += testHypotCase(3*d, 4*d, 5*d, 2.5); |
| d *= 2.0; // increase exponent by 1 |
| } |
| } |
| |
| // Test for monotonicity failures. Fix one argument and test |
| // two numbers before and two numbers after each chosen value; |
| // i.e. |
| // |
| // pcNeighbors[] = |
| // {nextDown(nextDown(pc)), |
| // nextDown(pc), |
| // pc, |
| // nextUp(pc), |
| // nextUp(nextUp(pc))} |
| // |
| // and we test that hypot(pcNeighbors[i]) <= hypot(pcNeighbors[i+1]) |
| { |
| double pcNeighbors[] = new double[5]; |
| double pcNeighborsHypot[] = new double[5]; |
| double pcNeighborsStrictHypot[] = new double[5]; |
| |
| |
| for(int i = -18; i <= 18; i++) { |
| double pc = Math.scalb(1.0, i); |
| |
| pcNeighbors[2] = pc; |
| pcNeighbors[1] = Math.nextDown(pc); |
| pcNeighbors[0] = Math.nextDown(pcNeighbors[1]); |
| pcNeighbors[3] = Math.nextUp(pc); |
| pcNeighbors[4] = Math.nextUp(pcNeighbors[3]); |
| |
| for(int j = 0; j < pcNeighbors.length; j++) { |
| pcNeighborsHypot[j] = Math.hypot(2.0, pcNeighbors[j]); |
| pcNeighborsStrictHypot[j] = StrictMath.hypot(2.0, pcNeighbors[j]); |
| } |
| |
| for(int j = 0; j < pcNeighborsHypot.length-1; j++) { |
| if(pcNeighborsHypot[j] > pcNeighborsHypot[j+1] ) { |
| failures++; |
| System.err.println("Monotonicity failure for Math.hypot on " + |
| pcNeighbors[j] + " and " + |
| pcNeighbors[j+1] + "\n\treturned " + |
| pcNeighborsHypot[j] + " and " + |
| pcNeighborsHypot[j+1] ); |
| } |
| |
| if(pcNeighborsStrictHypot[j] > pcNeighborsStrictHypot[j+1] ) { |
| failures++; |
| System.err.println("Monotonicity failure for StrictMath.hypot on " + |
| pcNeighbors[j] + " and " + |
| pcNeighbors[j+1] + "\n\treturned " + |
| pcNeighborsStrictHypot[j] + " and " + |
| pcNeighborsStrictHypot[j+1] ); |
| } |
| |
| |
| } |
| |
| } |
| } |
| |
| |
| return failures; |
| } |
| |
| static int testHypotCase(double input1, double input2, double expected) { |
| return testHypotCase(input1,input2, expected, 1); |
| } |
| |
| static int testHypotCase(double input1, double input2, double expected, |
| double ulps) { |
| int failures = 0; |
| if (expected < 0.0) { |
| throw new AssertionError("Result of hypot must be greater than " + |
| "or equal to zero"); |
| } |
| |
| // Test Math and StrictMath methods with no inputs negated, |
| // each input negated singly, and both inputs negated. Also |
| // test inputs in reversed order. |
| |
| for(int i = -1; i <= 1; i+=2) { |
| for(int j = -1; j <= 1; j+=2) { |
| double x = i * input1; |
| double y = j * input2; |
| failures += Tests.testUlpDiff("Math.hypot", x, y, |
| Math.hypot(x, y), expected, ulps); |
| failures += Tests.testUlpDiff("Math.hypot", y, x, |
| Math.hypot(y, x ), expected, ulps); |
| |
| failures += Tests.testUlpDiff("StrictMath.hypot", x, y, |
| StrictMath.hypot(x, y), expected, ulps); |
| failures += Tests.testUlpDiff("StrictMath.hypot", y, x, |
| StrictMath.hypot(y, x), expected, ulps); |
| } |
| } |
| |
| return failures; |
| } |
| |
| public static void main(String argv[]) { |
| int failures = 0; |
| |
| failures += testHypot(); |
| |
| if (failures > 0) { |
| System.err.println("Testing the hypot incurred " |
| + failures + " failures."); |
| throw new RuntimeException(); |
| } |
| } |
| |
| } |
