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/*
* Copyright (c) 2023, 2024, 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
* @bug 8301202
* @key randomness
* @library /test/lib
* @build jdk.test.lib.RandomFactory
* @build Tests
* @build FdlibmTranslit
* @build LogTests
* @run main LogTests
* @summary Tests for StrictMath.log
*/
import jdk.test.lib.RandomFactory;
public class LogTests {
private LogTests(){}
public static void main(String... args) {
int failures = 0;
failures += testLog();
failures += testAgainstTranslit();
if (failures > 0) {
System.err.println("Testing log incurred "
+ failures + " failures.");
throw new RuntimeException();
}
}
static int testLogCase(double input, double expected) {
return Tests.test("StrictMath.log(double)", input,
StrictMath::log, expected);
}
// Inputs where Math.log and StrictMath.log differ for at least
// one Math.log implementation.
static int testLog() {
int failures = 0;
double [][] testCases = {
{0x1.000000089cd6fp-43, -0x1.dce2a0697a102p4},
{0x1.0000000830698p182, 0x1.f89c7428dd67ap6},
{0x1.0000000744b3ap632, 0x1.b611ab2bd53cep8},
{0x1.000000037d81fp766, 0x1.0979b1dbc4a42p9},
{0x1.000000024028p991, 0x1.577455642bb92p9},
// Empirical worst-case points
{0x1.0ffea3878db6bp+0, 0x1.f07a0cca521fp-5},
{0x1.490af72a25a81p-1, -0x1.c4bf7ae48f078p-2},
{0x1.69e7aa6da2df5p-1, -0x1.634508c9adfp-2},
};
for (double[] testCase: testCases)
failures+=testLogCase(testCase[0], testCase[1]);
return failures;
}
// Initialize shared random number generator
private static java.util.Random random = RandomFactory.getRandom();
/**
* Test StrictMath.log against transliteration port of log.
*/
private static int testAgainstTranslit() {
int failures = 0;
double x;
// Test just above subnormal threshold...
x = Double.MIN_NORMAL;
failures += testRange(x, Math.ulp(x), 1000);
// ... and just below subnormal threshold ...
x = Math.nextDown(Double.MIN_NORMAL);
failures += testRange(x, -Math.ulp(x), 1000);
// Probe near decision points in the FDLIBM algorithm.
double[] decisionPoints = {
0x1.0p-1022,
0x1.0p-20,
};
for (double testPoint : decisionPoints) {
failures += testRangeMidpoint(testPoint, Math.ulp(testPoint), 1000);
}
x = Tests.createRandomDouble(random);
// Make the increment twice the ulp value in case the random
// value is near an exponent threshold. Don't worry about test
// elements overflowing to infinity if the starting value is
// near Double.MAX_VALUE.
failures += testRange(x, 2.0 * Math.ulp(x), 1000);
return failures;
}
private static int testRange(double start, double increment, int count) {
int failures = 0;
double x = start;
for (int i = 0; i < count; i++, x += increment) {
failures += testLogCase(x, FdlibmTranslit.log(x));
}
return failures;
}
private static int testRangeMidpoint(double midpoint, double increment, int count) {
int failures = 0;
double x = midpoint - increment*(count / 2) ;
for (int i = 0; i < count; i++, x += increment) {
failures += testLogCase(x, FdlibmTranslit.log(x));
}
return failures;
}
}
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