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comparison tests/test-exp.h @ 16577:7bea32ad5560

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exp* tests: More tests. * tests/test-exp.h: New file. * tests/test-exp.c: Include <float.h> and test-exp.h. (main): Invoke test_function. * tests/test-expf.c: Include <float.h> and test-exp.h. (main): Invoke test_function. * tests/test-expl.c: Include <float.h> and test-exp.h. (main): Invoke test_function. * modules/exp-tests (Files): Add tests/test-exp.h, tests/randomd.c. (Makefile.am): Add randomd.c to test_exp_SOURCES. * modules/expf-tests (Files): Add tests/test-exp.h, tests/randomf.c. (Makefile.am): Add randomf.c to test_expf_SOURCES. * modules/expl-tests (Files): Add tests/test-exp.h, tests/randoml.c. (Depends-on): Add 'float'. (Makefile.am): Add randoml.c to test_expl_SOURCES.
author Bruno Haible <bruno@clisp.org>
date Tue, 06 Mar 2012 03:05:14 +0100
parents
children 4d95f1c07c62
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16576:6c7c671909d3 16577:7bea32ad5560
1 /* Test of exp*() function family.
2 Copyright (C) 2012 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
16
17 static void
18 test_function (void)
19 {
20 int i;
21 int j;
22 const DOUBLE TWO_MANT_DIG =
23 /* Assume MANT_DIG <= 5 * 31.
24 Use the identity
25 n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */
26 (DOUBLE) (1U << ((MANT_DIG - 1) / 5))
27 * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5))
28 * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5))
29 * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5))
30 * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5));
31
32 /* Randomized tests. */
33 {
34 /* Error bound, in ulps. */
35 const DOUBLE err_bound =
36 (sizeof (DOUBLE) == sizeof (long double) ?
37 #if defined __i386__ && defined __FreeBSD__
38 /* On FreeBSD/x86 6.4, the 'long double' type really has only 53 bits of
39 precision in the compiler but 64 bits of precision at runtime. See
40 <http://lists.gnu.org/archive/html/bug-gnulib/2008-07/msg00063.html>.
41 The compiler has truncated all 'long double' literals in expl.c to
42 53 bits of precision. */
43 L_(1350.0)
44 #else
45 L_(4.0)
46 #endif
47 : L_(2.0));
48
49 for (i = 0; i < SIZEOF (RANDOM); i++)
50 {
51 DOUBLE x = L_(16.0) * RANDOM[i]; /* 0.0 <= x <= 16.0 */
52 DOUBLE y = EXP (x);
53 DOUBLE z = EXP (- x);
54 DOUBLE err = y * z - L_(1.0);
55 ASSERT (y > L_(0.0));
56 ASSERT (z > L_(0.0));
57 ASSERT (err > - err_bound / TWO_MANT_DIG
58 && err < err_bound / TWO_MANT_DIG);
59 }
60 }
61
62 {
63 /* Error bound, in ulps. */
64 const DOUBLE err_bound =
65 (sizeof (DOUBLE) == sizeof (long double) ?
66 #if defined __i386__ && defined __FreeBSD__
67 L_(2400.0)
68 #else
69 L_(24.0)
70 #endif
71 : L_(24.0));
72
73 for (i = 0; i < SIZEOF (RANDOM) / 5; i++)
74 for (j = 0; j < SIZEOF (RANDOM) / 5; j++)
75 {
76 DOUBLE x = L_(32.0) * RANDOM[i] - L_(16.0); /* -16.0 <= x <= 16.0 */
77 DOUBLE y = L_(32.0) * RANDOM[j] - L_(16.0); /* -16.0 <= y <= 16.0 */
78 DOUBLE z = - x - y;
79 /* Approximately x + y + z = 0. */
80 DOUBLE err = EXP (x) * EXP (y) * EXP (z) - L_(1.0);
81 ASSERT (err > - err_bound / TWO_MANT_DIG
82 && err < err_bound / TWO_MANT_DIG);
83 }
84 }
85 }
86
87 volatile DOUBLE x;
88 DOUBLE y;