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16733
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1 /* Test of log10*() function family. |
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2 Copyright (C) 2012 Free Software Foundation, Inc. |
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3 |
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4 This program is free software: you can redistribute it and/or modify |
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5 it under the terms of the GNU General Public License as published by |
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6 the Free Software Foundation; either version 3 of the License, or |
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7 (at your option) any later version. |
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8 |
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9 This program is distributed in the hope that it will be useful, |
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10 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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12 GNU General Public License for more details. |
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13 |
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14 You should have received a copy of the GNU General Public License |
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15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
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16 |
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17 static void |
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18 test_function (void) |
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19 { |
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20 int i; |
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21 int j; |
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22 const DOUBLE TWO_MANT_DIG = |
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23 /* Assume MANT_DIG <= 5 * 31. |
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24 Use the identity |
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25 n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */ |
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26 (DOUBLE) (1U << ((MANT_DIG - 1) / 5)) |
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27 * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5)) |
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28 * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5)) |
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29 * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5)) |
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30 * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5)); |
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31 |
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32 /* Pole. */ |
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33 { |
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34 DOUBLE z = LOG10 (L_(0.0)); |
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35 ASSERT (z == - HUGEVAL); |
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36 } |
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37 { |
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38 DOUBLE z = LOG10 (MINUS_ZERO); |
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39 ASSERT (z == - HUGEVAL); |
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40 } |
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41 |
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42 /* Randomized tests. */ |
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43 { |
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44 /* Error bound, in ulps. */ |
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45 const DOUBLE err_bound = |
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46 (sizeof (DOUBLE) > sizeof (double) ? |
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47 #if defined __i386__ && defined __FreeBSD__ |
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48 /* On FreeBSD/x86 6.4, the 'long double' type really has only 53 bits of |
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49 precision in the compiler but 64 bits of precision at runtime. See |
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50 <http://lists.gnu.org/archive/html/bug-gnulib/2008-07/msg00063.html>. |
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51 The compiler has truncated all 'long double' literals in log10l.c to |
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52 53 bits of precision. */ |
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53 L_(18.0) |
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54 #else |
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55 L_(3.0) |
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56 #endif |
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57 : L_(3.0)); |
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58 |
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59 for (i = 0; i < SIZEOF (RANDOM); i++) |
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60 { |
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61 DOUBLE x = L_(16.0) * RANDOM[i] + L_(1.0); /* 1.0 <= x <= 17.0 */ |
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62 DOUBLE y = LOG10 (x); |
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63 DOUBLE z = LOG10 (L_(1.0) / x); |
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64 DOUBLE err = y + z; |
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65 ASSERT (y >= L_(0.0)); |
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66 ASSERT (z <= L_(0.0)); |
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67 ASSERT (err > - err_bound / TWO_MANT_DIG |
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68 && err < err_bound / TWO_MANT_DIG); |
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69 } |
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70 } |
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71 |
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72 { |
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73 /* Error bound, in ulps. */ |
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74 const DOUBLE err_bound = |
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75 (sizeof (DOUBLE) > sizeof (double) ? |
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76 #if defined __i386__ && defined __FreeBSD__ |
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77 /* On FreeBSD/x86 6.4, the 'long double' type really has only 53 bits of |
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78 precision in the compiler but 64 bits of precision at runtime. See |
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79 <http://lists.gnu.org/archive/html/bug-gnulib/2008-07/msg00063.html>. |
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80 The compiler has truncated all 'long double' literals in log10l.c to |
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81 53 bits of precision. */ |
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82 L_(38.0) |
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83 #else |
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84 L_(5.0) |
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85 #endif |
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86 : L_(5.0)); |
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87 |
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16750
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88 for (i = 0; i < SIZEOF (RANDOM) / 5; i++) |
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89 for (j = 0; j < SIZEOF (RANDOM) / 5; j++) |
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16733
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90 { |
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91 DOUBLE x = L_(17.0) / (L_(16.0) - L_(15.0) * RANDOM[i]) - L_(1.0); |
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92 DOUBLE y = L_(17.0) / (L_(16.0) - L_(15.0) * RANDOM[j]) - L_(1.0); |
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93 /* 1/16 <= x,y <= 16 */ |
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94 DOUBLE z = L_(1.0) / (x * y); |
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95 /* Approximately x * y * z = 1. */ |
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96 DOUBLE err = LOG10 (x) + LOG10 (y) + LOG10 (z); |
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97 ASSERT (err > - err_bound / TWO_MANT_DIG |
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98 && err < err_bound / TWO_MANT_DIG); |
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99 } |
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100 } |
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101 } |
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102 |
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103 volatile DOUBLE x; |
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104 DOUBLE y; |
