1 /*
2 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /*
25 * @test
26 * @bug 4851638 4900189 4939441
27 * @summary Tests for {Math, StrictMath}.expm1
28 * @author Joseph D. Darcy
29 */
30
31 import sun.misc.DoubleConsts;
32 import sun.misc.FpUtils;
33
34 /*
35 * The Taylor expansion of expxm1(x) = exp(x) -1 is
36 *
37 * 1 + x/1! + x^2/2! + x^3/3| + ... -1 =
38 *
39 * x + x^2/2! + x^3/3 + ...
40 *
41 * Therefore, for small values of x, expxm1 ~= x.
42 *
43 * For large values of x, expxm1(x) ~= exp(x)
44 *
45 * For large negative x, expxm1(x) ~= -1.
46 */
47
48 public class Expm1Tests {
49
50 private Expm1Tests(){}
51
52 static final double infinityD = Double.POSITIVE_INFINITY;
126 // Test two numbers before and two numbers after each chosen
127 // value; i.e.
128 //
129 // pcNeighbors[] =
130 // {nextDown(nextDown(pc)),
131 // nextDown(pc),
132 // pc,
133 // nextUp(pc),
134 // nextUp(nextUp(pc))}
135 //
136 // and we test that expm1(pcNeighbors[i]) <= expm1(pcNeighbors[i+1])
137 {
138 double pcNeighbors[] = new double[5];
139 double pcNeighborsExpm1[] = new double[5];
140 double pcNeighborsStrictExpm1[] = new double[5];
141
142 for(int i = -50; i <= 50; i++) {
143 double pc = StrictMath.log(2)*i;
144
145 pcNeighbors[2] = pc;
146 pcNeighbors[1] = FpUtils.nextDown(pc);
147 pcNeighbors[0] = FpUtils.nextDown(pcNeighbors[1]);
148 pcNeighbors[3] = Math.nextUp(pc);
149 pcNeighbors[4] = Math.nextUp(pcNeighbors[3]);
150
151 for(int j = 0; j < pcNeighbors.length; j++) {
152 pcNeighborsExpm1[j] = Math.expm1(pcNeighbors[j]);
153 pcNeighborsStrictExpm1[j] = StrictMath.expm1(pcNeighbors[j]);
154 }
155
156 for(int j = 0; j < pcNeighborsExpm1.length-1; j++) {
157 if(pcNeighborsExpm1[j] > pcNeighborsExpm1[j+1] ) {
158 failures++;
159 System.err.println("Monotonicity failure for Math.expm1 on " +
160 pcNeighbors[j] + " and " +
161 pcNeighbors[j+1] + "\n\treturned " +
162 pcNeighborsExpm1[j] + " and " +
163 pcNeighborsExpm1[j+1] );
164 }
165
166 if(pcNeighborsStrictExpm1[j] > pcNeighborsStrictExpm1[j+1] ) {
167 failures++;
|
1 /*
2 * Copyright (c) 2003, 2011 Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /*
25 * @test
26 * @bug 4851638 4900189 4939441
27 * @summary Tests for {Math, StrictMath}.expm1
28 * @author Joseph D. Darcy
29 */
30
31 import sun.misc.DoubleConsts;
32
33 /*
34 * The Taylor expansion of expxm1(x) = exp(x) -1 is
35 *
36 * 1 + x/1! + x^2/2! + x^3/3| + ... -1 =
37 *
38 * x + x^2/2! + x^3/3 + ...
39 *
40 * Therefore, for small values of x, expxm1 ~= x.
41 *
42 * For large values of x, expxm1(x) ~= exp(x)
43 *
44 * For large negative x, expxm1(x) ~= -1.
45 */
46
47 public class Expm1Tests {
48
49 private Expm1Tests(){}
50
51 static final double infinityD = Double.POSITIVE_INFINITY;
125 // Test two numbers before and two numbers after each chosen
126 // value; i.e.
127 //
128 // pcNeighbors[] =
129 // {nextDown(nextDown(pc)),
130 // nextDown(pc),
131 // pc,
132 // nextUp(pc),
133 // nextUp(nextUp(pc))}
134 //
135 // and we test that expm1(pcNeighbors[i]) <= expm1(pcNeighbors[i+1])
136 {
137 double pcNeighbors[] = new double[5];
138 double pcNeighborsExpm1[] = new double[5];
139 double pcNeighborsStrictExpm1[] = new double[5];
140
141 for(int i = -50; i <= 50; i++) {
142 double pc = StrictMath.log(2)*i;
143
144 pcNeighbors[2] = pc;
145 pcNeighbors[1] = Math.nextDown(pc);
146 pcNeighbors[0] = Math.nextDown(pcNeighbors[1]);
147 pcNeighbors[3] = Math.nextUp(pc);
148 pcNeighbors[4] = Math.nextUp(pcNeighbors[3]);
149
150 for(int j = 0; j < pcNeighbors.length; j++) {
151 pcNeighborsExpm1[j] = Math.expm1(pcNeighbors[j]);
152 pcNeighborsStrictExpm1[j] = StrictMath.expm1(pcNeighbors[j]);
153 }
154
155 for(int j = 0; j < pcNeighborsExpm1.length-1; j++) {
156 if(pcNeighborsExpm1[j] > pcNeighborsExpm1[j+1] ) {
157 failures++;
158 System.err.println("Monotonicity failure for Math.expm1 on " +
159 pcNeighbors[j] + " and " +
160 pcNeighbors[j+1] + "\n\treturned " +
161 pcNeighborsExpm1[j] + " and " +
162 pcNeighborsExpm1[j+1] );
163 }
164
165 if(pcNeighborsStrictExpm1[j] > pcNeighborsStrictExpm1[j+1] ) {
166 failures++;
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