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 4347132 4939441
27 * @summary Tests for {Math, StrictMath}.cbrt
28 * @author Joseph D. Darcy
29 */
30
31 import sun.misc.DoubleConsts;
32
33 public class CubeRootTests {
34 private CubeRootTests(){}
35
36 static final double infinityD = Double.POSITIVE_INFINITY;
37 static final double NaNd = Double.NaN;
38
39 // Initialize shared random number generator
40 static java.util.Random rand = new java.util.Random();
41
42 static int testCubeRootCase(double input, double expected) {
43 int failures=0;
44
45 double minus_input = -input;
46 double minus_expected = -expected;
47
48 failures+=Tests.test("Math.cbrt(double)", input,
49 Math.cbrt(input), expected);
50 failures+=Tests.test("Math.cbrt(double)", minus_input,
51 Math.cbrt(minus_input), minus_expected);
52 failures+=Tests.test("StrictMath.cbrt(double)", input,
76 {+0.0, +0.0},
77 {-0.0, -0.0},
78 {+1.0, +1.0},
79 {-1.0, -1.0},
80 {+8.0, +2.0},
81 {-8.0, -2.0}
82 };
83
84 for(int i = 0; i < testCases.length; i++) {
85 failures += testCubeRootCase(testCases[i][0],
86 testCases[i][1]);
87 }
88
89 // Test integer perfect cubes less than 2^53.
90 for(int i = 0; i <= 208063; i++) {
91 double d = i;
92 failures += testCubeRootCase(d*d*d, (double)i);
93 }
94
95 // Test cbrt(2^(3n)) = 2^n.
96 for(int i = 18; i <= DoubleConsts.MAX_EXPONENT/3; i++) {
97 failures += testCubeRootCase(Math.scalb(1.0, 3*i),
98 Math.scalb(1.0, i) );
99 }
100
101 // Test cbrt(2^(-3n)) = 2^-n.
102 for(int i = -1; i >= DoubleConsts.MIN_SUB_EXPONENT/3; i--) {
103 failures += testCubeRootCase(Math.scalb(1.0, 3*i),
104 Math.scalb(1.0, i) );
105 }
106
107 // Test random perfect cubes. Create double values with
108 // modest exponents but only have at most the 17 most
109 // significant bits in the significand set; 17*3 = 51, which
110 // is less than the number of bits in a double's significand.
111 long exponentBits1 =
112 Double.doubleToLongBits(Math.scalb(1.0, 55)) &
113 DoubleConsts.EXP_BIT_MASK;
114 long exponentBits2=
115 Double.doubleToLongBits(Math.scalb(1.0, -55)) &
116 DoubleConsts.EXP_BIT_MASK;
117 for(int i = 0; i < 100; i++) {
118 // Take 16 bits since the 17th bit is implicit in the
119 // exponent
120 double input1 =
121 Double.longBitsToDouble(exponentBits1 |
122 // Significand bits
123 ((long) (rand.nextInt() & 0xFFFF))<<
124 (DoubleConsts.SIGNIFICAND_WIDTH-1-16));
125 failures += testCubeRootCase(input1*input1*input1, input1);
126
127 double input2 =
128 Double.longBitsToDouble(exponentBits2 |
129 // Significand bits
130 ((long) (rand.nextInt() & 0xFFFF))<<
131 (DoubleConsts.SIGNIFICAND_WIDTH-1-16));
132 failures += testCubeRootCase(input2*input2*input2, input2);
133 }
134
135 // Directly test quality of implementation properties of cbrt
136 // for values that aren't perfect cubes. Verify returned
137 // result meets the 1 ulp test. That is, we want to verify
138 // that for positive x > 1,
139 // y = cbrt(x),
140 //
141 // if (err1=x - y^3 ) < 0, abs((y_pp^3 -x )) < err1
142 // if (err1=x - y^3 ) > 0, abs((y_mm^3 -x )) < err1
143 //
144 // where y_mm and y_pp are the next smaller and next larger
145 // floating-point value to y. In other words, if y^3 is too
146 // big, making y larger does not improve the result; likewise,
147 // if y^3 is too small, making y smaller does not improve the
148 // result.
149 //
150 // ...-----|--?--|--?--|-----... Where is the true result?
151 // y_mm y y_pp
223 }
224
225 // Test monotonicity properites near perfect cubes; test two
226 // numbers before and two numbers after; i.e. for
227 //
228 // pcNeighbors[] =
229 // {nextDown(nextDown(pc)),
230 // nextDown(pc),
231 // pc,
232 // nextUp(pc),
233 // nextUp(nextUp(pc))}
234 //
235 // test that cbrt(pcNeighbors[i]) <= cbrt(pcNeighbors[i+1])
236 {
237
238 double pcNeighbors[] = new double[5];
239 double pcNeighborsCbrt[] = new double[5];
240 double pcNeighborsStrictCbrt[] = new double[5];
241
242 // Test near cbrt(2^(3n)) = 2^n.
243 for(int i = 18; i <= DoubleConsts.MAX_EXPONENT/3; i++) {
244 double pc = Math.scalb(1.0, 3*i);
245
246 pcNeighbors[2] = pc;
247 pcNeighbors[1] = Math.nextDown(pc);
248 pcNeighbors[0] = Math.nextDown(pcNeighbors[1]);
249 pcNeighbors[3] = Math.nextUp(pc);
250 pcNeighbors[4] = Math.nextUp(pcNeighbors[3]);
251
252 for(int j = 0; j < pcNeighbors.length; j++) {
253 pcNeighborsCbrt[j] = Math.cbrt(pcNeighbors[j]);
254 pcNeighborsStrictCbrt[j] = StrictMath.cbrt(pcNeighbors[j]);
255 }
256
257 for(int j = 0; j < pcNeighborsCbrt.length-1; j++) {
258 if(pcNeighborsCbrt[j] > pcNeighborsCbrt[j+1] ) {
259 failures++;
260 System.err.println("Monotonicity failure for Math.cbrt on " +
261 pcNeighbors[j] + " and " +
262 pcNeighbors[j+1] + "\n\treturned " +
263 pcNeighborsCbrt[j] + " and " +
264 pcNeighborsCbrt[j+1] );
265 }
266
267 if(pcNeighborsStrictCbrt[j] > pcNeighborsStrictCbrt[j+1] ) {
268 failures++;
269 System.err.println("Monotonicity failure for StrictMath.cbrt on " +
270 pcNeighbors[j] + " and " +
271 pcNeighbors[j+1] + "\n\treturned " +
272 pcNeighborsStrictCbrt[j] + " and " +
273 pcNeighborsStrictCbrt[j+1] );
274 }
275
276
277 }
278
279 }
280
281 // Test near cbrt(2^(-3n)) = 2^-n.
282 for(int i = -1; i >= DoubleConsts.MIN_SUB_EXPONENT/3; i--) {
283 double pc = Math.scalb(1.0, 3*i);
284
285 pcNeighbors[2] = pc;
286 pcNeighbors[1] = Math.nextDown(pc);
287 pcNeighbors[0] = Math.nextDown(pcNeighbors[1]);
288 pcNeighbors[3] = Math.nextUp(pc);
289 pcNeighbors[4] = Math.nextUp(pcNeighbors[3]);
290
291 for(int j = 0; j < pcNeighbors.length; j++) {
292 pcNeighborsCbrt[j] = Math.cbrt(pcNeighbors[j]);
293 pcNeighborsStrictCbrt[j] = StrictMath.cbrt(pcNeighbors[j]);
294 }
295
296 for(int j = 0; j < pcNeighborsCbrt.length-1; j++) {
297 if(pcNeighborsCbrt[j] > pcNeighborsCbrt[j+1] ) {
298 failures++;
299 System.err.println("Monotonicity failure for Math.cbrt on " +
300 pcNeighbors[j] + " and " +
301 pcNeighbors[j+1] + "\n\treturned " +
302 pcNeighborsCbrt[j] + " and " +
|
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 4347132 4939441
27 * @summary Tests for {Math, StrictMath}.cbrt
28 * @author Joseph D. Darcy
29 */
30
31 public class CubeRootTests {
32 private CubeRootTests(){}
33
34 static final double infinityD = Double.POSITIVE_INFINITY;
35 static final double NaNd = Double.NaN;
36
37 // Initialize shared random number generator
38 static java.util.Random rand = new java.util.Random();
39
40 static int testCubeRootCase(double input, double expected) {
41 int failures=0;
42
43 double minus_input = -input;
44 double minus_expected = -expected;
45
46 failures+=Tests.test("Math.cbrt(double)", input,
47 Math.cbrt(input), expected);
48 failures+=Tests.test("Math.cbrt(double)", minus_input,
49 Math.cbrt(minus_input), minus_expected);
50 failures+=Tests.test("StrictMath.cbrt(double)", input,
74 {+0.0, +0.0},
75 {-0.0, -0.0},
76 {+1.0, +1.0},
77 {-1.0, -1.0},
78 {+8.0, +2.0},
79 {-8.0, -2.0}
80 };
81
82 for(int i = 0; i < testCases.length; i++) {
83 failures += testCubeRootCase(testCases[i][0],
84 testCases[i][1]);
85 }
86
87 // Test integer perfect cubes less than 2^53.
88 for(int i = 0; i <= 208063; i++) {
89 double d = i;
90 failures += testCubeRootCase(d*d*d, (double)i);
91 }
92
93 // Test cbrt(2^(3n)) = 2^n.
94 for(int i = 18; i <= Double.MAX_EXPONENT/3; i++) {
95 failures += testCubeRootCase(Math.scalb(1.0, 3*i),
96 Math.scalb(1.0, i) );
97 }
98
99 // Test cbrt(2^(-3n)) = 2^-n.
100 for(int i = -1; i >= DoubleUtils.MIN_SUB_EXPONENT/3; i--) {
101 failures += testCubeRootCase(Math.scalb(1.0, 3*i),
102 Math.scalb(1.0, i) );
103 }
104
105 // Test random perfect cubes. Create double values with
106 // modest exponents but only have at most the 17 most
107 // significant bits in the significand set; 17*3 = 51, which
108 // is less than the number of bits in a double's significand.
109 long exponentBits1 =
110 Double.doubleToLongBits(Math.scalb(1.0, 55)) &
111 DoubleUtils.EXP_BIT_MASK;
112 long exponentBits2=
113 Double.doubleToLongBits(Math.scalb(1.0, -55)) &
114 DoubleUtils.EXP_BIT_MASK;
115 for(int i = 0; i < 100; i++) {
116 // Take 16 bits since the 17th bit is implicit in the
117 // exponent
118 double input1 =
119 Double.longBitsToDouble(exponentBits1 |
120 // Significand bits
121 ((long) (rand.nextInt() & 0xFFFF))<<
122 (DoubleUtils.SIGNIFICAND_WIDTH-1-16));
123 failures += testCubeRootCase(input1*input1*input1, input1);
124
125 double input2 =
126 Double.longBitsToDouble(exponentBits2 |
127 // Significand bits
128 ((long) (rand.nextInt() & 0xFFFF))<<
129 (DoubleUtils.SIGNIFICAND_WIDTH-1-16));
130 failures += testCubeRootCase(input2*input2*input2, input2);
131 }
132
133 // Directly test quality of implementation properties of cbrt
134 // for values that aren't perfect cubes. Verify returned
135 // result meets the 1 ulp test. That is, we want to verify
136 // that for positive x > 1,
137 // y = cbrt(x),
138 //
139 // if (err1=x - y^3 ) < 0, abs((y_pp^3 -x )) < err1
140 // if (err1=x - y^3 ) > 0, abs((y_mm^3 -x )) < err1
141 //
142 // where y_mm and y_pp are the next smaller and next larger
143 // floating-point value to y. In other words, if y^3 is too
144 // big, making y larger does not improve the result; likewise,
145 // if y^3 is too small, making y smaller does not improve the
146 // result.
147 //
148 // ...-----|--?--|--?--|-----... Where is the true result?
149 // y_mm y y_pp
221 }
222
223 // Test monotonicity properites near perfect cubes; test two
224 // numbers before and two numbers after; i.e. for
225 //
226 // pcNeighbors[] =
227 // {nextDown(nextDown(pc)),
228 // nextDown(pc),
229 // pc,
230 // nextUp(pc),
231 // nextUp(nextUp(pc))}
232 //
233 // test that cbrt(pcNeighbors[i]) <= cbrt(pcNeighbors[i+1])
234 {
235
236 double pcNeighbors[] = new double[5];
237 double pcNeighborsCbrt[] = new double[5];
238 double pcNeighborsStrictCbrt[] = new double[5];
239
240 // Test near cbrt(2^(3n)) = 2^n.
241 for(int i = 18; i <= Double.MAX_EXPONENT/3; i++) {
242 double pc = Math.scalb(1.0, 3*i);
243
244 pcNeighbors[2] = pc;
245 pcNeighbors[1] = Math.nextDown(pc);
246 pcNeighbors[0] = Math.nextDown(pcNeighbors[1]);
247 pcNeighbors[3] = Math.nextUp(pc);
248 pcNeighbors[4] = Math.nextUp(pcNeighbors[3]);
249
250 for(int j = 0; j < pcNeighbors.length; j++) {
251 pcNeighborsCbrt[j] = Math.cbrt(pcNeighbors[j]);
252 pcNeighborsStrictCbrt[j] = StrictMath.cbrt(pcNeighbors[j]);
253 }
254
255 for(int j = 0; j < pcNeighborsCbrt.length-1; j++) {
256 if(pcNeighborsCbrt[j] > pcNeighborsCbrt[j+1] ) {
257 failures++;
258 System.err.println("Monotonicity failure for Math.cbrt on " +
259 pcNeighbors[j] + " and " +
260 pcNeighbors[j+1] + "\n\treturned " +
261 pcNeighborsCbrt[j] + " and " +
262 pcNeighborsCbrt[j+1] );
263 }
264
265 if(pcNeighborsStrictCbrt[j] > pcNeighborsStrictCbrt[j+1] ) {
266 failures++;
267 System.err.println("Monotonicity failure for StrictMath.cbrt on " +
268 pcNeighbors[j] + " and " +
269 pcNeighbors[j+1] + "\n\treturned " +
270 pcNeighborsStrictCbrt[j] + " and " +
271 pcNeighborsStrictCbrt[j+1] );
272 }
273
274
275 }
276
277 }
278
279 // Test near cbrt(2^(-3n)) = 2^-n.
280 for(int i = -1; i >= DoubleUtils.MIN_SUB_EXPONENT/3; i--) {
281 double pc = Math.scalb(1.0, 3*i);
282
283 pcNeighbors[2] = pc;
284 pcNeighbors[1] = Math.nextDown(pc);
285 pcNeighbors[0] = Math.nextDown(pcNeighbors[1]);
286 pcNeighbors[3] = Math.nextUp(pc);
287 pcNeighbors[4] = Math.nextUp(pcNeighbors[3]);
288
289 for(int j = 0; j < pcNeighbors.length; j++) {
290 pcNeighborsCbrt[j] = Math.cbrt(pcNeighbors[j]);
291 pcNeighborsStrictCbrt[j] = StrictMath.cbrt(pcNeighbors[j]);
292 }
293
294 for(int j = 0; j < pcNeighborsCbrt.length-1; j++) {
295 if(pcNeighborsCbrt[j] > pcNeighborsCbrt[j+1] ) {
296 failures++;
297 System.err.println("Monotonicity failure for Math.cbrt on " +
298 pcNeighbors[j] + " and " +
299 pcNeighbors[j+1] + "\n\treturned " +
300 pcNeighborsCbrt[j] + " and " +
|