103 lines
2.7 KiB
C
103 lines
2.7 KiB
C
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#ifndef MY_THREADSAVE_RANDOM_GENERATOR
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#define MY_THREADSAVE_RANDOM_GENERATOR
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/******************************************************************************
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* File: mrand.h
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* Purpose: simple portable thread save random generator
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* ccording to Schrage
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* Author: M. Thaler, 5/2012, BSy
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* Version: v.fs20
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******************************************************************************/
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#include <sys/time.h>
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//******************************************************************************
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#define MMM_MR 2147483563
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#define AAA_MR 40014
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#define QQQ_MR 53668
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#define RRR_MR 12211
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#define MRAND_MAX (MMM_MR-1)
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//******************************************************************************
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typedef int rand_t;
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// seed ------------------------------------------------------------------------
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void rand_seed(rand_t *srand, int seed) {
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struct timeval prandom_seed;
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gettimeofday(&prandom_seed, NULL);
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if (seed > 0)
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*srand = seed;
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else
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*srand = (prandom_seed.tv_usec);
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}
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// integer random value -------------------------------------------------------
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// range 0 .. MRAND_MAX (inclusive)
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int rand_int(rand_t *srand) {
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int nx;
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nx = AAA_MR * (*srand % QQQ_MR) - RRR_MR * (*srand / QQQ_MR);
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*srand = (nx > 0) ? nx : nx + MMM_MR;
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return (*srand);
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}
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// float random value ---------------------------------------------------------
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// range 0.0 .. 1.0 (inclusive)
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float rand_float(rand_t *srand) {
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float fx;
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*srand = rand_int(srand);
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fx = (float)(*srand) / ((float)MRAND_MAX);
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return (fx);
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}
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// double random value --------------------------------------------------------
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// range 0.0 .. 1.0 (inclusive)
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double rand_double(rand_t *srand) {
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double fx;
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*srand = rand_int(srand);
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fx = (double)(*srand) / ((double)MRAND_MAX);
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return (fx);
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}
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// unsigned int random range --------------------------------------------------
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// range low .. high
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unsigned int rand_range(unsigned int low, unsigned int high, rand_t *srand) {
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unsigned int rv;
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double prop;
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prop = ((double)(high - low)) * rand_double(srand);
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rv = low + ((unsigned int) prop);
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return(rv);
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}
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// unsigned int probability ---------------------------------------------------
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// returns 0 or 1
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unsigned int rand_prob(double prob, rand_t *srand) {
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if (rand_double(srand) >= 1.0-prob)
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return 1;
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else
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return 0;
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}
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// unsigned int toss coin -----------------------------------------------------
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// returns 0 or 1
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unsigned int toss_coin(rand_t *srand) {
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if (rand_float(srand) >= 0.5)
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return 1;
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else
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return 0;
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}
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//******************************************************************************
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#endif
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