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16575
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1 /* Test of cbrt*() 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 /* Randomized tests. */ |
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33 for (i = 0; i < SIZEOF (RANDOM); i++) |
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34 { |
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35 DOUBLE x = L_(32.0) * RANDOM[i] - L_(16.0); /* -16.0 <= x <= 16.0 */ |
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36 DOUBLE y = CBRT (x); |
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37 DOUBLE err = y * y * y - x; |
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38 ASSERT (err > - L_(4.0) * L_(16.0) / TWO_MANT_DIG |
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39 && err < L_(4.0) * L_(16.0) / TWO_MANT_DIG); |
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40 } |
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41 |
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42 for (i = 0; i < SIZEOF (RANDOM) / 5; i++) |
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43 for (j = 0; j < SIZEOF (RANDOM) / 5; j++) |
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44 { |
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45 DOUBLE x = L_(32.0) * RANDOM[i] - L_(16.0); /* -16.0 <= x <= 16.0 */ |
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46 DOUBLE y = L_(32.0) * RANDOM[j] - L_(16.0); /* -16.0 <= y <= 16.0 */ |
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47 if (x != L_(0.0) && y != L_(0.0)) |
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48 { |
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49 DOUBLE z = L_(1.0) / (x * y); |
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50 /* Approximately x * y * z = 1. */ |
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51 DOUBLE p = CBRT (x) * CBRT (y) * CBRT (z); |
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52 ASSERT (p > L_(1.0) - L_(8.0) / TWO_MANT_DIG |
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53 && p < L_(1.0) + L_(8.0) / TWO_MANT_DIG); |
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54 } |
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55 } |
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56 } |
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57 |
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58 volatile DOUBLE x; |
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59 DOUBLE y; |
