35 lines
799 B
C++
35 lines
799 B
C++
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#include <math.h>
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#include <stdlib.h>
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#include <string.h>
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#include "distributions.h"
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#include "log.h"
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const char* distributions[] =
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{ "uniform", "exponential", "zipfian", "latest", NULL };
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distribution_t get_distribution(const char *name) {
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for (int i = 0; distributions[i] != NULL; i++)
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if (!strcmp(distributions[i], name))
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return (distribution_t) i;
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return (distribution_t) -1;
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}
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double generate_normal(double mean, double sd) {
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double U = drand48();
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double V = drand48();
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double N = sqrt(-2 * log(U)) * cos(2 * M_PI * V);
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return mean + sd * N;
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}
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double generate_poisson(double lambda) {
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if (lambda <= 0.0) return 0;
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double U = drand48();
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return -log(U)/lambda;
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}
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double generate_uniform(double lambda) {
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if (lambda <= 0.0) return 0;
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return 1.0 / lambda;
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}
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