Last change
on this file was
13625,
checked in by westram, 9 years ago
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- reintegrates 'pars' into 'trunk'
- adds:
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-
Property svn:eol-style set to
native
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Property svn:keywords set to
Author Date Id Revision
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File size:
1.8 KB
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1 | // =============================================================== // |
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2 | // // |
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3 | // File : admath.cxx // |
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4 | // Purpose : // |
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5 | // // |
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6 | // Institute of Microbiology (Technical University Munich) // |
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7 | // http://www.arb-home.de/ // |
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8 | // // |
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9 | // =============================================================== // |
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10 | |
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11 | #include <cmath> |
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12 | #include <ctime> |
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13 | |
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14 | #include "gb_local.h" |
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15 | |
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16 | double GB_log_fak(int n) { |
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17 | // returns log(n!) |
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18 | static int max_n = 0; |
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19 | static double *res = 0; |
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20 | |
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21 | if (n<=1) return 0.0; // log 1 = 0 |
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22 | |
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23 | if (n >= max_n) { |
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24 | double sum = 0; |
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25 | int i; |
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26 | freenull(res); |
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27 | max_n = n + 100; |
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28 | res = (double *)GB_calloc(sizeof(double), max_n); |
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29 | for (i=1; i<max_n; i++) { |
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30 | sum += log((double)i); |
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31 | res[i] = sum; |
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32 | } |
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33 | } |
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34 | return res[n]; |
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35 | } |
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36 | |
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37 | // ---------------------------------- |
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38 | // random number generation |
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39 | |
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40 | static int randomSeeded = 0; |
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41 | static unsigned usedSeed = 0; |
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42 | |
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43 | void GB_random_seed(unsigned seed) { |
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44 | /*! normally you should not use GB_random_seed. |
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45 | * Use it only to reproduce some result (e.g. in unittests) |
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46 | */ |
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47 | usedSeed = seed; |
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48 | srand(seed); |
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49 | randomSeeded = 1; |
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50 | } |
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51 | |
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52 | int GB_random(int range) { |
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53 | // produces a random number in range [0 .. range-1] |
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54 | if (!randomSeeded) GB_random_seed(time(0)); |
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55 | |
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56 | #if defined(DEBUG) |
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57 | if (range>RAND_MAX) { |
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58 | printf("Warning: range to big for random granularity (%i > %i)\n", range, RAND_MAX); |
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59 | } |
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60 | #endif // DEBUG |
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61 | |
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62 | return (int)(rand()*((double)range) / (RAND_MAX+1.0)); |
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63 | } |
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