Java example source code file (PowTests.java)
The PowTests.java Java example source code/*
* Copyright (c) 2004, 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 4984407 5033578
* @summary Tests for {Math, StrictMath}.pow
* @author Joseph D. Darcy
*/
public class PowTests {
private PowTests(){}
static final double infinityD = Double.POSITIVE_INFINITY;
static int testPowCase(double input1, double input2, double expected) {
int failures = 0;
failures += Tests.test("StrictMath.pow(double, double)", input1, input2,
StrictMath.pow(input1, input2), expected);
failures += Tests.test("Math.pow(double, double)", input1, input2,
Math.pow(input1, input2), expected);
return failures;
}
static int testStrictPowCase(double input1, double input2, double expected) {
int failures = 0;
failures += Tests.test("StrictMath.pow(double, double)", input1, input2,
StrictMath.pow(input1, input2), expected);
return failures;
}
static int testNonstrictPowCase(double input1, double input2, double expected) {
int failures = 0;
failures += Tests.test("Math.pow(double, double)", input1, input2,
Math.pow(input1, input2), expected);
return failures;
}
/*
* Test for bad negation implementation.
*/
static int testPow() {
int failures = 0;
double [][] testCases = {
{-0.0, 3.0, -0.0},
{-0.0, 4.0, 0.0},
{-infinityD, -3.0, -0.0},
{-infinityD, -4.0, 0.0},
};
for (double[] testCase : testCases) {
failures+=testPowCase(testCase[0], testCase[1], testCase[2]);
}
return failures;
}
/*
* Test cross-product of different kinds of arguments.
*/
static int testCrossProduct() {
int failures = 0;
double testData[] = {
Double.NEGATIVE_INFINITY,
/* > -oo */ -Double.MAX_VALUE,
/**/ (double)Long.MIN_VALUE,
/**/ (double) -((1L<<53)+2L),
/**/ (double) -((1L<<53)),
/**/ (double) -((1L<<53)-1L),
/**/ -((double)Integer.MAX_VALUE + 4.0),
/**/ (double)Integer.MIN_VALUE - 1.0,
/**/ (double)Integer.MIN_VALUE,
/**/ (double)Integer.MIN_VALUE + 1.0,
/**/ -Math.PI,
/**/ -3.0,
/**/ -Math.E,
/**/ -2.0,
/**/ -1.0000000000000004,
/* < -1.0 */ -1.0000000000000002, // nextAfter(-1.0, -oo)
-1.0,
/* > -1.0 */ -0.9999999999999999, // nextAfter(-1.0, +oo)
/* > -1.0 */ -0.9999999999999998,
/**/ -0.5,
/**/ -1.0/3.0,
/* < 0.0 */ -Double.MIN_VALUE,
-0.0,
+0.0,
/* > 0.0 */ +Double.MIN_VALUE,
/**/ +1.0/3.0,
/**/ +0.5,
/**/ +0.9999999999999998,
/* < +1.0 */ +0.9999999999999999, // nextAfter(-1.0, +oo)
+1.0,
/* > 1.0 */ +1.0000000000000002, // nextAfter(+1.0, +oo)
/**/ +1.0000000000000004,
/**/ +2.0,
/**/ +Math.E,
/**/ +3.0,
/**/ +Math.PI,
/**/ -(double)Integer.MIN_VALUE - 1.0,
/**/ -(double)Integer.MIN_VALUE,
/**/ -(double)Integer.MIN_VALUE + 1.0,
/**/ (double)Integer.MAX_VALUE + 4.0,
/**/ (double) ((1L<<53)-1L),
/**/ (double) ((1L<<53)),
/**/ (double) ((1L<<53)+2L),
/**/ -(double)Long.MIN_VALUE,
/* < oo */ Double.MAX_VALUE,
Double.POSITIVE_INFINITY,
Double.NaN
};
double NaN = Double.NaN;
for(double x: testData) {
for(double y: testData) {
boolean testPass = false;
double expected=NaN;
double actual;
// First, switch on y
if( Double.isNaN(y)) {
expected = NaN;
} else if (y == 0.0) {
expected = 1.0;
} else if (Double.isInfinite(y) ) {
if(y > 0) { // x ^ (+oo)
if (Math.abs(x) > 1.0) {
expected = Double.POSITIVE_INFINITY;
} else if (Math.abs(x) == 1.0) {
expected = NaN;
} else if (Math.abs(x) < 1.0) {
expected = +0.0;
} else { // x is NaN
assert Double.isNaN(x);
expected = NaN;
}
} else { // x ^ (-oo)
if (Math.abs(x) > 1.0) {
expected = +0.0;
} else if (Math.abs(x) == 1.0) {
expected = NaN;
} else if (Math.abs(x) < 1.0) {
expected = Double.POSITIVE_INFINITY;
} else { // x is NaN
assert Double.isNaN(x);
expected = NaN;
}
} /* end Double.isInfinite(y) */
} else if (y == 1.0) {
expected = x;
} else if (Double.isNaN(x)) { // Now start switching on x
assert y != 0.0;
expected = NaN;
} else if (x == Double.NEGATIVE_INFINITY) {
expected = (y < 0.0) ? f2(y) :f1(y);
} else if (x == Double.POSITIVE_INFINITY) {
expected = (y < 0.0) ? +0.0 : Double.POSITIVE_INFINITY;
} else if (equivalent(x, +0.0)) {
assert y != 0.0;
expected = (y < 0.0) ? Double.POSITIVE_INFINITY: +0.0;
} else if (equivalent(x, -0.0)) {
assert y != 0.0;
expected = (y < 0.0) ? f1(y): f2(y);
} else if( x < 0.0) {
assert y != 0.0;
failures += testStrictPowCase(x, y, f3(x, y));
failures += testNonstrictPowCase(x, y, f3ns(x, y));
continue;
} else {
// go to next iteration
expected = NaN;
continue;
}
failures += testPowCase(x, y, expected);
} // y
} // x
return failures;
}
static boolean equivalent(double a, double b) {
return Double.compare(a, b) == 0;
}
static double f1(double y) {
return (intClassify(y) == 1)?
Double.NEGATIVE_INFINITY:
Double.POSITIVE_INFINITY;
}
static double f2(double y) {
return (intClassify(y) == 1)?-0.0:0.0;
}
static double f3(double x, double y) {
switch( intClassify(y) ) {
case 0:
return StrictMath.pow(Math.abs(x), y);
// break;
case 1:
return -StrictMath.pow(Math.abs(x), y);
// break;
case -1:
return Double.NaN;
// break;
default:
throw new AssertionError("Bad classification.");
// break;
}
}
static double f3ns(double x, double y) {
switch( intClassify(y) ) {
case 0:
return Math.pow(Math.abs(x), y);
// break;
case 1:
return -Math.pow(Math.abs(x), y);
// break;
case -1:
return Double.NaN;
// break;
default:
throw new AssertionError("Bad classification.");
// break;
}
}
static boolean isFinite(double a) {
return (0.0*a == 0);
}
/**
* Return classification of argument: -1 for non-integers, 0 for
* even integers, 1 for odd integers.
*/
static int intClassify(double a) {
if(!isFinite(a) || // NaNs and infinities
(a != Math.floor(a) )) { // only integers are fixed-points of floor
return -1;
}
else {
// Determine if argument is an odd or even integer.
a = StrictMath.abs(a); // absolute value doesn't affect odd/even
if(a+1.0 == a) { // a > maximum odd floating-point integer
return 0; // Large integers are all even
}
else { // Convert double -> long and look at low-order bit
long ell = (long) a;
return ((ell & 0x1L) == (long)1)?1:0;
}
}
}
public static void main(String [] argv) {
int failures = 0;
failures += testPow();
failures += testCrossProduct();
if (failures > 0) {
System.err.println("Testing pow incurred "
+ failures + " failures.");
throw new RuntimeException();
}
}
}
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