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/*
* Copyright (c) 2015, 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
* @bug 8139688
* @key randomness
* @library /test/lib
* @build jdk.test.lib.RandomFactory
* @build Tests
* @build FdlibmTranslit
* @build ExpTests
* @run main ExpTests
* @summary Tests specifically for StrictMath.exp
*/
import jdk.test.lib.RandomFactory;
/**
* The role of this test is to verify that the FDLIBM exp algorithm is
* being used by running golden file style tests on values that may
* vary from one conforming exponential implementation to another.
*/
public class ExpTests {
private ExpTests(){}
public static void main(String [] argv) {
int failures = 0;
failures += testExp();
failures += testAgainstTranslit();
if (failures > 0) {
System.err.println("Testing the exponential incurred "
+ failures + " failures.");
throw new RuntimeException();
}
}
// From the fdlibm source, the overflow threshold in hex is:
// 0x4086_2E42_FEFA_39EF.
static final double EXP_OVERFLOW_THRESH = Double.longBitsToDouble(0x4086_2E42_FEFA_39EFL);
// From the fdlibm source, the underflow threshold in hex is:
// 0xc087_4910_D52D_3051L.
static final double EXP_UNDERFLOW_THRESH = Double.longBitsToDouble(0xc087_4910_D52D_3051L);
static int testExp() {
int failures = 0;
double [][] testCases = {
// Some of these could be moved to common Math/StrictMath exp testing.
{Double.NaN, Double.NaN},
{Double.MAX_VALUE, Double.POSITIVE_INFINITY},
{Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY},
{Double.NEGATIVE_INFINITY, +0.0},
{EXP_OVERFLOW_THRESH, 0x1.ffff_ffff_fff2ap1023},
{Math.nextUp(EXP_OVERFLOW_THRESH), Double.POSITIVE_INFINITY},
{Math.nextDown(EXP_UNDERFLOW_THRESH), +0.0},
{EXP_UNDERFLOW_THRESH, +Double.MIN_VALUE},
};
for(double[] testCase: testCases)
failures+=testExpCase(testCase[0], testCase[1]);
return failures;
}
static int testExpCase(double input, double expected) {
int failures = 0;
failures+=Tests.test("StrictMath.exp(double)", input,
StrictMath.exp(input), expected);
return failures;
}
// Initialize shared random number generator
private static java.util.Random random = RandomFactory.getRandom();
/**
* Test StrictMath.exp against transliteration port of exp.
*/
private static int testAgainstTranslit() {
int failures = 0;
double[] decisionPoints = {
// Near overflow threshold
EXP_OVERFLOW_THRESH - 512*Math.ulp(EXP_OVERFLOW_THRESH),
// Near underflow threshold
EXP_UNDERFLOW_THRESH - 512*Math.ulp(EXP_UNDERFLOW_THRESH),
// Straddle algorithm conditional checks
Double.longBitsToDouble(0x4086_2E42_0000_0000L - 512L),
Double.longBitsToDouble(0x3fd6_2e42_0000_0000L - 512L),
Double.longBitsToDouble(0x3FF0_A2B2_0000_0000L - 512L),
Double.longBitsToDouble(0x3e30_0000_0000_0000L - 512L),
// Other notable points
Double.MIN_NORMAL - Math.ulp(Double.MIN_NORMAL)*512,
-Double.MIN_VALUE*512,
};
for (double decisionPoint : decisionPoints) {
double ulp = Math.ulp(decisionPoint);
failures += testRange(decisionPoint - 1024*ulp, ulp, 1_024);
}
// Try out some random values
for (int i = 0; i < 100; i++) {
double x = Tests.createRandomDouble(random);
failures += testRange(x, Math.ulp(x), 100);
}
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 += testExpCase(x, FdlibmTranslit.Exp.compute(x));
}
return failures;
}
}
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