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#include <time.h>
#include <math.h>
#include <stc/crandom.h>
#include <stc/cstr.h>
// Declare int -> int hashmap. Uses typetag 'ii' for ints.
#define i_key int
#define i_val int
#define i_tag ii
#include <stc/cmap.h>
// Declare int vector with entries from the cmap.
#define i_val cmap_ii_value
#define i_less(x, y) x->first < y->first
#define i_tag ii
#include <stc/cvec.h>
int main()
{
enum {N = 10000000};
const double Mean = -12.0, StdDev = 6.0, Scale = 74;
printf("Demo of gaussian / normal distribution of %d random samples\n", N);
// Setup random engine with normal distribution.
uint64_t seed = (uint64_t)time(NULL);
stc64_t rng = stc64_new(seed);
stc64_normalf_t dist = stc64_normalf_new(Mean, StdDev);
// Create and init histogram vec and map with defered destructors:
c_auto (cvec_ii, histvec)
c_auto (cmap_ii, histmap)
{
c_forrange (N) {
int index = (int)round( stc64_normalf(&rng, &dist) );
cmap_ii_insert(&histmap, index, 0).ref->second += 1;
}
// Transfer map to vec and sort it by map keys.
c_foreach (i, cmap_ii, histmap)
cvec_ii_push(&histvec, (cmap_ii_value){i.ref->first, i.ref->second});
cvec_ii_sort(&histvec);
// Print the gaussian bar chart
c_foreach (i, cvec_ii, histvec) {
int n = (int)(i.ref->second * StdDev * Scale * 2.5 / (double)N);
if (n > 0) {
printf("%4d ", i.ref->first);
c_forrange (n) printf("*");
puts("");
}
}
}
}
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