Last change
on this file since 984 was
984,
checked in by sam, 11 years ago
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test: add a 10-line example program that computes Pi to the 150th digit.
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Property svn:keywords set to
Id
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File size:
953 bytes
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1 | // |
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2 | // Lol Engine - Sample math program: compute Pi |
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3 | // |
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4 | // Copyright: (c) 2005-2011 Sam Hocevar <sam@hocevar.net> |
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5 | // This program is free software; you can redistribute it and/or |
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6 | // modify it under the terms of the Do What The Fuck You Want To |
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7 | // Public License, Version 2, as published by Sam Hocevar. See |
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8 | // http://sam.zoy.org/projects/COPYING.WTFPL for more details. |
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9 | // |
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10 | |
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11 | #if defined HAVE_CONFIG_H |
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12 | # include "config.h" |
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13 | #endif |
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14 | |
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15 | #include "core.h" |
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16 | |
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17 | using namespace lol; |
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18 | |
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19 | int main(int argc, char **argv) |
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20 | { |
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21 | /* Approximate Pi using Machin's formula: 16*atan(1/5)-4*atan(1/239) */ |
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22 | real sum = 0.0, x0 = 5.0, x1 = 239.0; |
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23 | real const m0 = -x0 * x0, m1 = -x1 * x1, r16 = 16.0, r4 = 4.0; |
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24 | |
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25 | /* Degree 240 is required for 512-bit mantissa precision */ |
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26 | for (int i = 1; i < 240; i += 2) |
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27 | { |
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28 | sum += r16 / (x0 * (real)i) - r4 / (x1 * (real)i); |
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29 | x0 *= m0; |
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30 | x1 *= m1; |
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31 | } |
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32 | |
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33 | sum.print(); |
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34 | |
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35 | return EXIT_SUCCESS; |
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36 | } |
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37 | |
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